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Author Topic: IPCC possible scenario: 9 C over next century or so  (Read 79001 times)

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #100 on: October 23, 2014, 03:58:21 AM »
More recent than the 3rd:
Week beginning on October 12, 2014: 395.55 ppm
Weekly value from 1 year ago: 393.60 ppm

Or "about 2ppm above the concentration for the same time last year"

But really, individual weekly numbers are essentially irrelevant.

Here's the very clear long-term trend:

Decade                 Total Increase        Annual Rate of Increase

2004 –  2013              20.71 ppm                     2.07 ppm per year

1994 –  2003               18.70 ppm                     1.87 ppm per year

1984 –  1993                14.04 ppm                     1.40 ppm per year

1974 –  1983               13.35 ppm                     1.34 ppm per year

1964 –  1973               10.69 ppm                     1.07 ppm per year

1960 –  1963                 3.02 ppm                     0.75 ppm per year


http://co2now.org/Current-CO2/CO2-Trend/acceleration-of-atmospheric-co2.html

One week or even a couple years one direction or the other is not enough to know whether there has been a significant change in this long-term trend.

" if you think this is evidence that co2 emissions for 2014 will be [lower] than [long term rates] then you are a complete idiot." Fixed that for you.


And who said anything about 2014 being lower?

ASLR posted a chart which he claimed showed we were following RCP8.5.  I said that up to 2013 the figures followed the other RCPs just as well, and that it was only in 2014 that co2 jumped up to follow RCP8.5, and that 2014 is only a projection that hasn't happened yet.  ASLR countered with the fact the 2014 co2 keeling stats.  I stated that the 2014 stats showed a decrease in growth over the last year and noted that you can't read much into one year due to other factors, such as the ocean.


All,

Anyone can download the specific RCP GHG concentrations and radiative forcings at mid-year at the following website:

http://www.pik-potsdam.de/~mmalte/rcps/

Per this official data at mid-year (June 30th) 2014 ,RCP 8.5 specified CO2 to be 399.00ppm, and at mid-year 2015, RCP 8.5 specified CO2 to be 401.62. 

I will let those better qualified than me determine whether the current atmosphere CO2 concentrations are slightly above or essentially at these RCP 8.5 values.

Best,
ASLR
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viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #101 on: October 23, 2014, 04:33:12 AM »
Per this official data at mid-year (June 30th) 2014 ,RCP 8.5 specified CO2 to be 399.00ppm, and at mid-year 2015, RCP 8.5 specified CO2 to be 401.62.


Interesting. 399ppm daily, weekly or half–yearly per June 30th?

I have a feeling CO2 levels could sky–rocket during 2015 if a strong Niño stirs up the waters that are already emitting CO2 (oceans until very recently were considered CO2 sinks).

And as we know, there is already enough heat in the Arctic Ocean to melt all the ice many times over.
[]

Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #102 on: October 23, 2014, 10:51:30 AM »

All,

Anyone can download the specific RCP GHG concentrations and radiative forcings at mid-year at the following website:

http://www.pik-potsdam.de/~mmalte/rcps/

Per this official data at mid-year (June 30th) 2014 ,RCP 8.5 specified CO2 to be 399.00ppm, and at mid-year 2015, RCP 8.5 specified CO2 to be 401.62. 

I will let those better qualified than me determine whether the current atmosphere CO2 concentrations are slightly above or essentially at these RCP 8.5 values.

Best,
ASLR


actual Co2 increase rate 2008-2013 2.07ppm/year
RCP8.5 increase rate 2.332ppm/year
RCP6 increase rate 2.1ppm/year
RCP4 increase rate 2.166ppm/year
RCP2.6 increase rate 2.264ppm/year

The main point I think is its too early to tell which is the closest.  The RCPs haven't really started to diverge as is shown by the fact that the increase rate is not in the the same order that they will end up in.  However the mid range concentrations look to the closest to what is actually happening.

I'm too lazy to look at other things such as longer periods - which I'd expect to show all the RCPs closer together, or to look at other GHGs such as methane which I have idea what that would show.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #103 on: October 23, 2014, 11:53:28 AM »
Careful here, part of the "de-inflation" of this decade over the last was due to a reduction in airborne fraction. There are a few theories as to why this happened (Hansen, for instance: http://www.huffingtonpost.com/dr-james-hansen/doubling-down-on-our-faustian-bargain_b_2989535.html).

Note here too that there's significant interdecadal variability within that list. Note the 84-93 rate was barely higher than the 74-83 rate, despite a strong increase in emissions over the period.

From a political and statistical point of view, using 2005 is a logical choice if you want to show the biggest decreases possible. It was the last great pre-recession year (the bubble started bursting in 2006). Trends for labor force participation rate and employment have been down since that time, and we also started our gas boom shortly thereafter. If we were more serious about a real statistical representation, we'd be using a decadal average for a starting baseline for CO2 reductions.

And as a kind of side bar: Remember, cumulative emissions are what counts.


As I am traveling and do not have time to respond to the different posts, I will reply to Csnavywx as I agree that cumulative emissions and not rates are what counts.  The first attached image by the IEA is a little bit old (it is what I have when traveling) compares the 1990 - 2011 cumulative CO2 emissions vs the AR4 SRES scenario (see the second figure as to how to compare SRES and RCP scenarios).  The IEA figure shows the historical dip in CO2 due to the 2008 financial crisis (show one does need to be careful about variability (due to various factors including economics, ENSO, plant growth variations etc.)  But even considering the variability, the evidence gives a high probability that we are more likely following the high end of the IPCC emission scenarios than the low end.

This is not only true for CO2 but also for almost all of the GHG atmospheric concentrations, as indicated for methane in the third attached image and for nitrous oxide in the fourth attached image (both showing the 2014 Mauna Loa data), as compared to the following mid-year RCP 8.5 (I take this to be the values on June 30th) of 1823.655 and 1837.966, for methane in 2014 and 2015 respectively, and of 326.17 and 327.01, for nitrous oxide in 2014 and 2015, respectively.

Again, I do not have a crystal ball, and I do not know what radiative forcing will happen in the future; but I believe that it is unwise to assume that we are not following a BAU pathway now, and that unless we make a real effort (such as carbon price) we may well remain on a BAU pathway for sometime to come.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #104 on: October 23, 2014, 11:23:44 PM »


Scenario:  The warming rate may be 50% higher than the top end of this range to provide 9 degrees of warming by 2100.  Discuss?  Or laugh at?
Climate change:  Prepare for the worst, hope for the best, expect the middle.

wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #105 on: October 24, 2014, 01:19:47 AM »
"Discuss"

OK. One set of graphs by one dude doesn't tell us much, especially since they only go to 2050 making it hard to even assess the status of your curious claim. Note also that the title of the thread says nothing about 2100 any more.

Here are some other graphs, these from NCADAC. Please do discuss. Or laugh, if you wish, while you can.

Laugh while you can monkey boy






« Last Edit: October 24, 2014, 01:33:11 AM by wili »
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Lennart van der Linde

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #106 on: October 24, 2014, 08:15:46 AM »
wili,
Are we talking Celsius or Fahrenheit?

F.Tnioli

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #107 on: October 24, 2014, 12:56:11 PM »
As I am traveling and do not have time to respond to the different posts, I will reply to Csnavywx as I agree that cumulative emissions and not rates are what counts.  The first attached image by the IEA is a little bit old (it is what I have when traveling) compares the 1990 - 2011 cumulative CO2 emissions vs the AR4 SRES scenario (see the second figure as to how to compare SRES and RCP scenarios).  The IEA figure shows the historical dip in CO2 due to the 2008 financial crisis (show one does need to be careful about variability (due to various factors including economics, ENSO, plant growth variations etc.)  But even considering the variability, the evidence gives a high probability that we are more likely following the high end of the IPCC emission scenarios than the low end.

This is not only true for CO2 but also for almost all of the GHG atmospheric concentrations, as indicated for methane in the third attached image and for nitrous oxide in the fourth attached image (both showing the 2014 Mauna Loa data), as compared to the following mid-year RCP 8.5 (I take this to be the values on June 30th) of 1823.655 and 1837.966, for methane in 2014 and 2015 respectively, and of 326.17 and 327.01, for nitrous oxide in 2014 and 2015, respectively.

Again, I do not have a crystal ball, and I do not know what radiative forcing will happen in the future; but I believe that it is unwise to assume that we are not following a BAU pathway now, and that unless we make a real effort (such as carbon price) we may well remain on a BAU pathway for sometime to come.
You "believe" in it, huh. Well, unlike you, i don't "believe" in it; i _know_ it. And i know that even if real effort ("such as carbon price" and much more than that) will be made, - we'll still follow higher end of carbon emission scenarios, or even above.

It's rather simple logic and relatively few facts of life which leads to this conclusion. I'll present them for your consideration.

1. At this time and for at least several decades into the future, billions of humans on Earth each consume goods and services which are 1) critically important for their survival and b) can only be provided via burning hundreds kilograms or even tons of fossil fuels per capita per year. Example: modern food production requires fossil fuels (mechanization, fertilizers, transportation) to produce enough food to feed 7+ billions humans. There is NO other known method to produce that much food - not even third of it.

2. At this time and for at least few generations of people into the future, dominant consumption pattern - is "consumerism". Humans consume much more than they actually need. Example. They "like" meat, and billions of humans who can "afford" to eat meat every day - do so. They are not bothered about grain, water, pollution and other costs of growing beef and such. This is one direct consequence of "consumer culture" promoted in mass media, which, in turn, is one direct consequence of "free market competition" between large corporations (which have more than enough money and influence to design and use mass media "advertisements", including hidden and indirect ones).

3. There is the "tragedy of commons" and peer pressure. Majority of humans do NOT change to cleaner, less-polluting and less-carbon-intensive ways of life when a) it is not their property which suffers as a result of their anti-Gaia behavior, and b) majority of their peers are not doing it. This is a direct consequence of "private property" concept perpetuated by capitalistic societies. Defining what is "mine" automatically define what is "not mine", which leads to tragedy of commons. As long as capitalistic mindset prevail, this block will continue to be a major factor. Sadly, better (than capitalism) alternative is not known, so far; socialism proved time and time again to be only a dream, not realistically possible in practice (always get corrupted).

4. There is the "amplification of complexity and efficiency by prolonged use" phenomena in technologies. Best illustrated by example of internal combustion engine: by the time it was just invented - middle XIX century, was it, - it wasn't popular, or any efficient, or any complex. Steam machines ruled the world of large vehicles like trains and ships, and were much more complex than any internal-combustion engine of the time. Used and built in great numbers, steam engines grew much more efficient and complex simply because they were built and used in such great numbers: the latter fact caused so many engineers to invent and patent improvements for steam machines, so many technicians and operators to experiment and find better methods and regimes of operation, etc. And then, early XXth century, internal combustion engines, slowly developed bit by bit during previous decades and improved by visionaries like Diesel and Ford, went to be mass-produced and mass-used for smaller applications (cars, generators, etc). And once again, mere facts of being produced in great numbers, used by millions, - caused so much more innovation, invention and improvement to happen to internal combustion engines. Very soon, internal combustion engines became so much more refined, advanced and complex that they became more efficient than steam engines on trains and smaller ships. Plus, aviation was born. Internal combustion engines for all those vehicles had to differ dramatically between themselves, which further diversified the science of internal combustion engine, made them even more complex and efficient. Today, we have ICEs of all sorts, from tiny ones used in plane modelling sport - to huge diesel-electric submarine ones.

Similar effect, and on similar scale, is happening with fossil fuel extraction. Done for decades on a world-wide scale, dozens gigatons every year last few decades, - the science and engineering of fossil fuel extraction attracted lots and lots of talented eggheads and engineers. They enhanced the technology further and further. The process is going on even now. Shale oil and gas, nearly a dozen of non-traditional methods of oil extraction from once rich, but nowadays nearly "exhausted" sources, very sophisticated oil and gas finding methods, etc etc. Platforms at sea, several-kilometers-deep holes into the ground. All those things are very complex and require massive amount of science and development. Which oil and gas and coal businesses get - they have the scale and the pay to afford it. So it's kind of promotes itself, R&D happens dozens to hundreds times faster for fossil fuels than it ever was for alternative fuel sources. And this situation will remain as long as fossil fuels power over 85% of the world (counting both electricity AND all sorts of other fossil fuel applications - plastics, chemistry, transportation, machine oils, asphalt, etc). That's why mankind _can't_ beat efficiency of fossil fuels; for every improvement of, say, solar-thermal electricity generation - there are dozens or hundreds of comparable efficiency improvements in fossil fuel power generation and/or fossil fuel extraction.

5. Infrastructure inertia and continuity. See, billions of people now own devices and/or vehicles which demand (primarily) fossil fuels as their energy source. Every time an average world citizen turns on his TV - he burns some coal and gas, since over 70% of the world electricity comes from burning those; every time someone drives his car - he burns some oil (or, for electric cars - some coal and gas, since it uses electricity primarily generated by oil and gas). Every time someone flies a plane, eats a burger (created and transported mainly with energy of fossil fuels), boils some rice (grown and transported with fossil-fuel-powered vehicles, - and boiled most likely by burning some fuel, as well), - list goes on and on. The key thing here - people _own_ things their lives depend on, and most of those things are designed to work from fossil fuel energy. We talk WHOLE WORLD infrastructure here, most of which is fossil-fuel based. It took more than a hundred years to build it. And most bits and pieces are someone's property. It is naive to expect people will willingly toss their property away; it is naive to expect much or most of this world infrastructure could be replaced by something much more complex (alternative energy is more complex, sadly, than simply burning fossil fuels) in less than another hundred years; and it is naive to expect mankind to function "somehow" without burning fossil fuels AND without having adequate infrastructure for functioning mainly from non-fossil energy source(s).


Conclusion. Facts above are more than enough, together, to clearly see that no carbon price, no amount of legislation, and even, no amount of "real effort" can prevent the world from following higher-end carbon emissions scenarios for at least few decades ahead. There are only two things which can prevent it. First, planetary catastrophe (global nuclear war; sudden and catastrophic collapse of much or most of Greenland ice sheet into the ocean, causing mega-tsunami around the world and several meters of nearly instant sea level rise; large asteroid hit; etc). Second - rapid, massive and global reduction of human populations, by an order of magnitude or so (i.e., down to 10% or less of current population - to 700 millions or below), which would mean unnatural death of most humans alive - be it unprecedentally powerful epidemic, or some organism genetically engineered to destroy most humans, or something else of the sort. Anything less will fail to alter mankind carbon emissions simply because most of mankind is now dependent so massively and critically on all the fossil fuel burning.

P.S. It is illuminating to compare carbon emissions graph (since 19th century to nowadays) with world population graph. In a sense, fossil fuels are nothing less than a lifeblood of modern mankind. It can no less reduce fossil fuel burning than a human could reduce volume of blood in his system; yes, _some_ reduction can be done, - and if really desperate, even rather large reduction, something on the order of 50%, i.e. reducing it to half, - but anything much more than that leads to death - for both human body if we talk blood, and for mankind if we talk fossil fuels. The task of switching to alternative energy source for mankind is akin to switching to some GREEN blood for human body, - means, different blood cells, different compound which carry oxygen to tissues, different bone morrow, different genes - and lots of them - for human being, and most likely lots of changes within all major organs and tissues of the body. That task is possible to do for intelligent beings working together long enough time - for both mankind and human body; the latter, can be altered by geneticists, but it'd take long time to create such a "green-color-blood human"; the former - quite similarly, takes lots of scientists and engineers working together for  decades, creating alternative fuel sources (alternate electricity sources is not enough - different sort of fuel for planes, ships, buses, trucks, agriculture machinery, etc would also be needed), and then more decades to implement all the tech - to create billions of vehicles and devices to replace old ones, to pay for all that, to convince owners to change from old ones to new ones, etc. This is the ONLY way how it could actually work in practice, and no amount of carbon price will change it. Raising carbon price sky high "right now" - this year, or next year, or some time 2020 - will only result in millions of bankruptcies and billions of dead and hungry people worldwide, since there is no alternative infrastructure for vast majority of places and individuals yet; in fact, there is still even no alternative technology able to provide base-load power, nor globally-enough amount of non-fossil-fuel vehicle fuel. We don't even know - as a mankind, - _how_ exactly to replace our fossil-fuel-based infrastructure; we don't even know if it's actually possible at all. Still lots of years of R&D to do, here - and no guarantee of success. That's why we _need_ to recognize: we will continue higher-end carbon emissions path for several decades into the future at very least; we _will_ get consequences to it; we _will_ need to learn how to live with that. And it will be harder and harder to work on cleaner tech and infrastructure as things get progressively worse. There is nothing to "believe" in here - this all is already well _known_. It is just that so many people - especially in the media, - are willing and/or ordered to pretend this is not the case. Don't let them fool you. Think for yourself.
« Last Edit: October 24, 2014, 01:44:42 PM by F.Tnioli »

wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #108 on: October 24, 2014, 02:02:36 PM »
LvdL wrote: "Are we talking Celsius or Fahrenheit?"

MH didn't specify--another reason his attempted point was so ill formed. The graphs I posted are F and clearly show that 9F (at least) is near or well within possible projected temps by the end of the century. But in any case the main claim is that there are IPCC projections that show 9 C temperature rises in a little over a century from now. That is simply a fact. Why anyone would find such a fact laughable is beyond me.

FT, nicely made points. I'm sure someone will point out that the very fact that ICE replaced steam means that another replacement is possible. But such replacements generally take decades, time we don't have at this point. We are indeed in the midst of entering the age of consequences.

I would also point out that over a third of modern ag goes to purposes other than direct consumption by humans, including nearly all of the corn and the soybean crop. So moving away from high meat consumption and corn- or soy-based biofuels would add a huge 'cushion' for conversion away from ff-intense industrial ag. But all of that is not to belittle your main point. We are not moving in these directions--just the opposite.

Still a good idea to point out how we could, in theory, reduce our emissions rapidly with relatively small negative (and considerable positive) potential consequences. 
« Last Edit: October 24, 2014, 02:11:23 PM by wili »
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

tombond

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #109 on: October 24, 2014, 03:44:15 PM »
Since 1900 carbon emissions have grown at an average rate of 2.5% per year.
The only period of slow down (reduced to 1.5% annually) was during the nuclear rollout between 1975 and 1995 when 400 nuclear power plants were constructed.
Since 1995, emission growth has reverted to the long term average rate of 2.5% per year.
The forecast emissions growth for 2014 is 2.5%.
Even to meet the RCP 8.5 scenario requires emissions growth to be reduced to a mean rate of 1.3% per year for the remainder of this century.
Currently even achieving this modest slowdown seems unlikely.

Data from;

http://www.pik-potsdam.de/~mmalte/rcps/
http://co2now.org/Current-CO2/CO2-Now/global-carbon-emissions.html

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #110 on: October 24, 2014, 06:09:55 PM »
"Discuss"


The following reference and the associated extract and the first attached image indicate that mean global temperature would have increased, during the recent hiatus period, at the rate projected by CMIP5 if not for the variable factors cited below (eg ENSO, volcanoes and incorrect mean global temperature measurements):

Markus Huber & Reto Knutti, (2014), "Natural variability, radiative forcing and climate response in the recent hiatus reconciled", Nature Geoscience, Volume: 7, Pages: 651–656, doi:10.1038/ngeo2228

http://www.nature.com/ngeo/journal/v7/n9/full/ngeo2228.html


Abstract: "Global mean surface warming over the past 15 years or so has been less than in earlier decades and than simulated by most climate models. Natural variability, a reduced radiative forcing, a smaller warming response to atmospheric carbon dioxide concentrations and coverage bias in the observations have been identified as potential causes. However, the explanations of the so-called ‘warming hiatus’ remain fragmented and the implications for long-term temperature projections are unclear. Here we estimate the contribution of internal variability associated with the El Niño/Southern Oscillation (ENSO) using segments of unforced climate model control simulations that match the observed climate variability. We find that ENSO variability analogous to that between 1997 or 1998 and 2012 leads to a cooling trend of about −0.06 °C. In addition, updated solar and stratospheric aerosol forcings from observations explain a cooling trend of similar magnitude (−0.07 °C). Accounting for these adjusted trends we show that a climate model of reduced complexity with a transient climate response of about 1.8 °C is consistent with the temperature record of the past 15 years, as is the ensemble mean of the models in the Coupled Model Intercomparison Project Phase 5 (CMIP5). We conclude that there is little evidence for a systematic overestimation of the temperature response to increasing atmospheric CO2 concentrations in the CMIP5 ensemble."

The following extract and caption for the first attached image are from the following related Internet article:

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/aug/25/unpacking-unpaused-global-warming-climate-models-right

Extract: "Putting it all together, we have 0.17°C observed surface warming according to Cowtan & Way, and 0.13°C cooling from natural influences. If those natural factors hadn’t caused cooling since 1998, we would have seen 0.3°C global surface warming, right in line with climate model projections."

Figure Caption: "Mean of CMIP5 climate model ensemble surface temperature projections unadjusted (dotted orange) and adjusted for internal variability & external forcings (solid orange), vs. Met Office (solid black) and Cowtan & Way (dashed black) observed surface temperatures. Source; Nature Geoscience; Huber & Knutti (2014)."

See also:
http://www.skepticalscience.com/unpacking-unpaused-global-warming-models-right.html

And see the second attached figure related to the following research:

Cowtan, K. and Way, R. G. (2014), Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends. Q.J.R. Meteorol. Soc., 140: 1935–1944. doi: 10.1002/qj.2297

http://onlinelibrary.wiley.com/doi/10.1002/qj.2297/pdf

Abstract: "Incomplete global coverage is a potential source of bias in global temperature reconstructions if the unsampled regions are not uniformly distributed over the planet's surface. The widely used Hadley Centre–Climatic Reseach Unit Version 4 (HadCRUT4) dataset covers on average about 84% of the globe over recent decades, with the unsampled regions being concentrated at the poles and over Africa. Three existing reconstructions with near-global coverage are examined, each suggesting that HadCRUT4 is subject to bias due to its treatment of unobserved regions.
Two alternative approaches for reconstructing global temperatures are explored, one based on an optimal interpolation algorithm and the other a hybrid method incorporating additional information from the satellite temperature record. The methods are validated on the basis of their skill at reconstructing omitted sets of observations. Both methods provide results superior to excluding the unsampled regions, with the hybrid method showing particular skill around the regions where no observations are available.
Temperature trends are compared for the hybrid global temperature reconstruction and the raw HadCRUT4 data. The widely quoted trend since 1997 in the hybrid global reconstruction is two and a half times greater than the corresponding trend in the coverage-biased HadCRUT4 data. Coverage bias causes a cool bias in recent temperatures relative to the late 1990s, which increases from around 1998 to the present. Trends starting in 1997 or 1998 are particularly biased with respect to the global trend. The issue is exacerbated by the strong El Niño event of 1997–1998, which also tends to suppress trends starting during those years."

http://www.skepticalscience.com/cowtan_way_surface_temperature_data_update.html

Unfortunately, the Huber & Knutti (2014) CMIP5 surface temperature projections do not include more recent findings such as those by:

Durack et al (2014), "Quantifying Underestimates of Long-term Upper-Ocean Warming", Nature Climate Change (2014) doi:10.1038/nclimate2389

http://www-pcmdi.llnl.gov/about/staff/Durack/dump/oceanwarming/140926a_Duracketal_UpperOceanWarming.pdf
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #111 on: October 24, 2014, 06:41:30 PM »
While RCP 8.5 is the only AR5 scenario with appreciable methane emissions (see the first line of the table below).  However, if we continue down our current BAU path for two to three more decades, then there are a number of natural sources of methane emissions that may well exceed the allowances included in the RCP 8.5 scenario.  While I cannot accurately identify all of these sources, nor the likely amounts of their emissions before 2100; nevertheless, it is interesting to make an effort to approximate the likely emissions of four key likely sources  that may contribute significant amounts of methane beyond that considered by RCP 8.5, as summarized in the following table (see the third attached image). 

First, Schuur  and Abbott (2011); their survey of 41 permafrost experts indicated that due both to more dynamic melting mechanisms and to the fact that the permafrost is now estimated to emit 2.7% of the release carbon as methane; that the combined CO2 equivalent cumulative emissions from the permafrost by 2040 will be between 30 to 63 billion tonnes, and by 2100 will increase to between 232 to 380 billion tonnes (assuming a linear flux rate from 2040 to 2100 this implies a flux of between 6.7 to 10.6 billion tonnes/yr of CO2 equivalent [or as a carbon equivalent of: 1.8 to 2.9 GtC/yr]).

Second, in a two-part study by scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Los Alamos National Laboratory utilized a scenario based on a combination of two computer models of how climate change could impact the millions of tons of methane frozen in sediment beneath the Arctic Ocean.  In the initial phase of the project they found that buried deposits of methane hydrates, will decompose as the global temperature increases and the oceans warm. In the second phase, the scientists found that methane would then seep into the Arctic Ocean and gradually overwhelm the marine environment’s ability to break down the gas. Supplies of oxygen, nutrients, and trace metals required by methane-eating microbes would dwindle year-by-year as more methane enters the water. After three decades of methane release, much of the methane may bubble to the surface, where it has the potential to accelerate climate change.  The author's (Elliot et al. 2011) conclusions include:
"The vast Arctic shelf supports massive hydrate reservoirs, and many are close to the edge of stability [Archer, 2007].  Since these deposits are often located in the depth range of recently ventilated North Atlantic water masses, relatively small increases in temperature due to climate change may result in dissociation [Lamarque, 2008].  In the present study, methane flow from warming clathrates is calculated by porous-media simulation [Reagan and Moridis, 2008]."
The first attached image from an ESM indicates (that following a BAU scenario) that the warm ocean currents from the North Atlantic are likely to abruptly increase their heat transfer into the Arctic Basin around 2030 (see table with my estimates of emissions based on Elliot et al 2011 and supporting data).

Third, Bastviken et al 2011 provided the explicit 2040 emission rate below, which I extrapolated to 2100.

Fourth, while controversial, in 2010, Natalia Shakhova and colleagues at the International Arctic Research Center in Fairbanks, Alaska, predicted 50 gigatonnes of methane could be released from the East Siberian Shelf in the next 50 years, either as a steady leak or a dramatic belch over just a year or two. However, personally, I find Shakhova's 2010 scenario too unlikely for my tastes, therefore, while the Elliot et al 2011 (see my discussion of this second source, above) atmospheric methane contributions potentially comes from super-saturation of the Arctic Ocean with methane (leading to a release of methane to the atmosphere); in this fourth source I postulate a limited "Clathrate Gun", triggered by an increase of warm ocean currents entering the Arctic Ocean starting in 2030 (see the first attached image) together with High AO patterns (see the second attached image) that send a warm ocean current along the continental slope of the East Siberian Arctic Shelf, ESAS that causes submarine landslides (due to melting the hydrates along the slope face thus weakening the insitu soil shear strength) resulting in relatively rapid releases of methane gas that bubbles up directly to the surface, resulting in emissions as indicated in the table.

Caption for first attached image: "ESM Projections of Arctic Ocean Heat Transport"

Caption for second attached image: "Schematic Representation of Arctic Ocean Circulation Patterns Under Low and High Arctic Oscillation Indices, from Morison et al. 2012"

Finally, the methane emission rates presented in the table justify the use of the findings from Isaksen et al's 7 x CH4 case for calculating a revised GWP for methane, as follows:
As the radiative forcing in a 50-year time horizon for 4 x CH4 additional emission of 0.80 GtCH4/yr is 2.2 Wm-2, and as the radiative forcing for the current methane emissions is 0.48 Wm-2, thus an updated GWP for methane, assuming the occurrence of Isaksen et al's 4 x CH4 case in 2040, would be: 33 (per Shindell et al 2009) times (2.2/[0.8 + 0.48]) divided by (0.54/0.48) = 50 by 2100.
 
If the GWP of methane increases to 50 by 2100 then the RCP 8.5 scenario will significantly under-estimate global warming by the end of this century.


Bastviken, D., Tranvik, L.J., Downing, J.A., Crill, P.M., and Enrich-Prast, A. (2011), "Freshwater Methane Emissions Offset the Continental Carbon Sink", Science, Vol 331, pp. 50.

Elliott, S., Maltrud, M., Reagan, M., Moridis, G., and Cameron-Smith, P., (2011), "Marine methane cycle simulations for the period of early global warming", Journal of Geophysical Research, Vol. 116, G01010, doi: 10.1029/2010JG00 1300.

Isaksen, I. S. A., Gauss M., Myhre, G., Walter Anthony, K. M.  and Ruppel, C.,  (2011), "Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions", Global Biogeochem. Cycles, 25, GB2002, doi:10.1029/2010GB003845

Schuur, E.A.G. and Abbott, B., (2011), "High risk of permafrost thaw", Nature, 480, 32-33, Dec. 2011.
« Last Edit: October 24, 2014, 06:48:10 PM by AbruptSLR »
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #112 on: October 24, 2014, 08:39:16 PM »
Sulfur dioxide is the most significant component of the negative feedback associated with aerosols, and the first attached image indicates that RCP 8.5 has been discounting sulfur dioxide from the atmosphere since about 2005 and continues doing so through 2100.   The second & third attached images (see captions below) show the estimated SO₂ emissions (according to Klimont et al 2014).  Comparing these graphs one sees that so far the observed SO₂ emissions reasonable track the RCP 8.5 assumptions; however, if China accelerates their rate of SO₂ emission reductions (which China has promised to do), then global warming may accelerate:

Z Klimont, S J Smith and J Cofala, (2013), "The last decade of global anthropogenic sulfur dioxide: 2000–2011 emissions", Environ. Res. Lett. 8 014003, doi:10.1088/1748-9326/8/1/014003

http://iopscience.iop.org/1748-9326/8/1/014003/article

Caption for the second attached image: "Sectorial trend in global, China, and Indian SO2 emissions since 1990, Tg SO2. Note different scales: i.e., India about 1/3 of China and the latter 1/3 of the world emissions."

Caption for the third attached image: "Global sulfur dioxide emissions from the current study as compared to several previous inventories, including EDGAR 4.1, EDGAR 4.2, and Smith et al (2011). A bar for the uncertainty estimate for the Smith et al (2011), 2005 emissions estimate is shown. Also shown are the global SO2 estimate for the four RCP scenarios. All emission estimates exclude open burning from grasslands, savannahs, forests, and deforestation."
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #113 on: October 24, 2014, 08:56:38 PM »
The linked reference found that aerosol-cloud associated changes in the amount of the clouds and changes of their internal properties are both equally important in their contribution to cooling our planet. Moreover, they found that the total impact from the influence of aerosols on this type of cloud is almost double that estimated in the latest report of the United Nations Intergovernmental Panel on Climate Change.  These findings indicate: (a) that the masking influence of aerosols during the faux hiatus period was higher than the CMIP5 models assumed (indicating that ECS is likely higher than the CMIP5 models assume, including in RCP 8.5); and (b)  global warming will likely accelerate as China begins to clean-up its air pollution:

Yi-Chun Chen, Matthew W. Christensen, Graeme L. Stephens & John H. Seinfeld, (2014), "Satellite-based estimate of global aerosol–cloud radiative forcing by marine warm clouds", Nature Geoscience, doi:10.1038/ngeo2214

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2214.html

Abstract: "Changes in aerosol concentrations affect cloud albedo and Earth’s radiative balance. Aerosol radiative forcing from pre-industrial time to the present due to the effect of atmospheric aerosol levels on the micro- and macrophysics of clouds bears the largest uncertainty among external influences on climate change. Of all cloud forms, low-level marine clouds exert the largest impact on the planet’s albedo. For example, a 6% increase in the albedo of global marine stratiform clouds could offset the warming that would result from a doubling of atmospheric CO2 concentrations. Marine warm cloud properties are thought to depend on aerosol levels and large-scale dynamic or thermodynamic states. Here we present a comprehensive analysis of multiple measurements from the A-Train constellation of Earth-observing satellites, to quantify the radiative forcing exerted by aerosols interacting with marine clouds. Specifically, we analyse observations of co-located aerosols and clouds over the world’s oceans for the period August 2006–April 2011, comprising over 7.3 million CloudSat single-layer marine warm cloud pixels. We find that thermodynamic conditions—that is, tropospheric stability and humidity in the free troposphere—and the state of precipitation act together to govern the cloud liquid water responses to the presence of aerosols and the strength of aerosol–cloud radiative forcing."
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #114 on: October 25, 2014, 01:45:11 AM »
LvdL wrote: "Are we talking Celsius or Fahrenheit?"

MH didn't specify--another reason his attempted point was so ill formed. The graphs I posted are F and clearly show that 9F (at least) is near or well within possible projected temps by the end of the century. But in any case the main claim is that there are IPCC projections that show 9 C temperature rises in a little over a century from now. That is simply a fact. Why anyone would find such a fact laughable is beyond me.

The charts I posted had Celcius all through them. 

There are no IPCC projections showing 9 C warming.  The top end of the uncertainy range for RCP8.5 is about 6 degrees.  The 9 degrees is something that ASLR just made up.  He multiplied the median climate sensitivity of 3 by 1.5 to be equivelant to a high climate sensitivity of 4.5.  This ignores the fact that equilibrium climate sensitivity is not relevant to projections over the next century, but rather transit climate sensitivity, as there are significant issue of time lags.  If climate sensitivity is higher, it is likely that time lags are also longer, otherwise we would have seen a greater amount of warming over the last century.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #115 on: October 25, 2014, 01:56:29 AM »
Since 1900 carbon emissions have grown at an average rate of 2.5% per year.
The only period of slow down (reduced to 1.5% annually) was during the nuclear rollout between 1975 and 1995 when 400 nuclear power plants were constructed.
Since 1995, emission growth has reverted to the long term average rate of 2.5% per year.
The forecast emissions growth for 2014 is 2.5%.
Even to meet the RCP 8.5 scenario requires emissions growth to be reduced to a mean rate of 1.3% per year for the remainder of this century.
Currently even achieving this modest slowdown seems unlikely.

Data from;

http://www.pik-potsdam.de/~mmalte/rcps/
http://co2now.org/Current-CO2/CO2-Now/global-carbon-emissions.html


Wind power is currently 4% of our electricity and growing by 25% a year.  If compound growth can be expected to continue indefinitely then 100% of our electricity will come from wind power in 15 years.  Arguments based on the assumption that compound growth will continue are silly. 

There are always limits on growth, and RCP8.5 assumes the weakest limits on growth that expert economists  who study this type of thing think reasonable.  For instance consider peak oil.  Some consider that oil production has already peaked.  The current wikipedia article on peak oil states that dates after 2030 are generally considered implausible.  RCP8.5 has a peak oil sometime around 2070.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #116 on: October 25, 2014, 02:07:58 AM »
"Discuss"


The following reference and the associated extract and the first attached image indicate that mean global temperature would have increased, during the recent hiatus period, at the rate projected by CMIP5 if not for the variable factors cited below (eg ENSO, volcanoes and incorrect mean global temperature measurements):

Markus Huber & Reto Knutti, (2014), "Natural variability, radiative forcing and climate response in the recent hiatus reconciled", Nature Geoscience, Volume: 7, Pages: 651–656, doi:10.1038/ngeo2228

http://www.nature.com/ngeo/journal/v7/n9/full/ngeo2228.html


Abstract: "Global mean surface warming over the past 15 years or so has been less than in earlier decades and than simulated by most climate models. Natural variability, a reduced radiative forcing, a smaller warming response to atmospheric carbon dioxide concentrations and coverage bias in the observations have been identified as potential causes. However, the explanations of the so-called ‘warming hiatus’ remain fragmented and the implications for long-term temperature projections are unclear. Here we estimate the contribution of internal variability associated with the El Niño/Southern Oscillation (ENSO) using segments of unforced climate model control simulations that match the observed climate variability. We find that ENSO variability analogous to that between 1997 or 1998 and 2012 leads to a cooling trend of about −0.06 °C. In addition, updated solar and stratospheric aerosol forcings from observations explain a cooling trend of similar magnitude (−0.07 °C). Accounting for these adjusted trends we show that a climate model of reduced complexity with a transient climate response of about 1.8 °C is consistent with the temperature record of the past 15 years, as is the ensemble mean of the models in the Coupled Model Intercomparison Project Phase 5 (CMIP5). We conclude that there is little evidence for a systematic overestimation of the temperature response to increasing atmospheric CO2 concentrations in the CMIP5 ensemble."

The following extract and caption for the first attached image are from the following related Internet article:

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/aug/25/unpacking-unpaused-global-warming-climate-models-right

Extract: "Putting it all together, we have 0.17°C observed surface warming according to Cowtan & Way, and 0.13°C cooling from natural influences. If those natural factors hadn’t caused cooling since 1998, we would have seen 0.3°C global surface warming, right in line with climate model projections."

Figure Caption: "Mean of CMIP5 climate model ensemble surface temperature projections unadjusted (dotted orange) and adjusted for internal variability & external forcings (solid orange), vs. Met Office (solid black) and Cowtan & Way (dashed black) observed surface temperatures. Source; Nature Geoscience; Huber & Knutti (2014)."

See also:
http://www.skepticalscience.com/unpacking-unpaused-global-warming-models-right.html

And see the second attached figure related to the following research:

Cowtan, K. and Way, R. G. (2014), Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends. Q.J.R. Meteorol. Soc., 140: 1935–1944. doi: 10.1002/qj.2297

http://onlinelibrary.wiley.com/doi/10.1002/qj.2297/pdf

Abstract: "Incomplete global coverage is a potential source of bias in global temperature reconstructions if the unsampled regions are not uniformly distributed over the planet's surface. The widely used Hadley Centre–Climatic Reseach Unit Version 4 (HadCRUT4) dataset covers on average about 84% of the globe over recent decades, with the unsampled regions being concentrated at the poles and over Africa. Three existing reconstructions with near-global coverage are examined, each suggesting that HadCRUT4 is subject to bias due to its treatment of unobserved regions.
Two alternative approaches for reconstructing global temperatures are explored, one based on an optimal interpolation algorithm and the other a hybrid method incorporating additional information from the satellite temperature record. The methods are validated on the basis of their skill at reconstructing omitted sets of observations. Both methods provide results superior to excluding the unsampled regions, with the hybrid method showing particular skill around the regions where no observations are available.
Temperature trends are compared for the hybrid global temperature reconstruction and the raw HadCRUT4 data. The widely quoted trend since 1997 in the hybrid global reconstruction is two and a half times greater than the corresponding trend in the coverage-biased HadCRUT4 data. Coverage bias causes a cool bias in recent temperatures relative to the late 1990s, which increases from around 1998 to the present. Trends starting in 1997 or 1998 are particularly biased with respect to the global trend. The issue is exacerbated by the strong El Niño event of 1997–1998, which also tends to suppress trends starting during those years."

http://www.skepticalscience.com/cowtan_way_surface_temperature_data_update.html

Unfortunately, the Huber & Knutti (2014) CMIP5 surface temperature projections do not include more recent findings such as those by:

Durack et al (2014), "Quantifying Underestimates of Long-term Upper-Ocean Warming", Nature Climate Change (2014) doi:10.1038/nclimate2389

http://www-pcmdi.llnl.gov/about/staff/Durack/dump/oceanwarming/140926a_Duracketal_UpperOceanWarming.pdf


There are plenty of reasons why the future warming rate may increase above the current slower than expected rate.  However we are currently sitting at the bottom end of projections and a claim that we will be above the top end of ICCP projections is extraordinary, and requires strong evidence. 

On Durack, as I've pointed out on the thread on that paper it is not a given that sensitivity be increased due to this result.  Climate sensitivity would likely be increased if the total top of atmosphere radiative balance was increased.  When calculating the global heat budget Church et al take the measurement of top of atmosphere as a given and then calculate aerosol forcing as the residual amount required to balance the other measured budget items such as ocean heat uptake.  If the Church et al analysis was repeated with a higher ocean heat uptake this would result in a lesser aerosol cooling factor, which would imply that Durack implies a lower climate sensitivity not higher.
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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #117 on: October 25, 2014, 02:17:26 AM »
The linked reference found that aerosol-cloud associated changes in the amount of the clouds and changes of their internal properties are both equally important in their contribution to cooling our planet. Moreover, they found that the total impact from the influence of aerosols on this type of cloud is almost double that estimated in the latest report of the United Nations Intergovernmental Panel on Climate Change.  These findings indicate: (a) that the masking influence of aerosols during the faux hiatus period was higher than the CMIP5 models assumed (indicating that ECS is likely higher than the CMIP5 models assume, including in RCP 8.5); and (b)  global warming will likely accelerate as China begins to clean-up its air pollution:

Yi-Chun Chen, Matthew W. Christensen, Graeme L. Stephens & John H. Seinfeld, (2014), "Satellite-based estimate of global aerosol–cloud radiative forcing by marine warm clouds", Nature Geoscience, doi:10.1038/ngeo2214

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2214.html

Abstract: "Changes in aerosol concentrations affect cloud albedo and Earth’s radiative balance. Aerosol radiative forcing from pre-industrial time to the present due to the effect of atmospheric aerosol levels on the micro- and macrophysics of clouds bears the largest uncertainty among external influences on climate change. Of all cloud forms, low-level marine clouds exert the largest impact on the planet’s albedo. For example, a 6% increase in the albedo of global marine stratiform clouds could offset the warming that would result from a doubling of atmospheric CO2 concentrations. Marine warm cloud properties are thought to depend on aerosol levels and large-scale dynamic or thermodynamic states. Here we present a comprehensive analysis of multiple measurements from the A-Train constellation of Earth-observing satellites, to quantify the radiative forcing exerted by aerosols interacting with marine clouds. Specifically, we analyse observations of co-located aerosols and clouds over the world’s oceans for the period August 2006–April 2011, comprising over 7.3 million CloudSat single-layer marine warm cloud pixels. We find that thermodynamic conditions—that is, tropospheric stability and humidity in the free troposphere—and the state of precipitation act together to govern the cloud liquid water responses to the presence of aerosols and the strength of aerosol–cloud radiative forcing."


Where does this paper find that total aerosol forcings are double what the IPCC assume?  It certainly isn't in the abstract which talks about the forcing factor due to the influence of aerosols on clouds, which is only one part of the total forcing for aerosol and doesn't mention any figures.  If I've interpreted the charts correctly they are quoting a forcing of 0.6w/m2 for clouds.  Compare this to Hansen's model E forcing for indirect aerosol effect of 1w/m2, which I think is the same thing? 

The rest of the paper is paywalled.  As far as I can tell this suggest the aerosol forcing is weaker than previously assumed, not stronger.
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #118 on: October 25, 2014, 04:21:24 AM »
LvdL wrote: "Are we talking Celsius or Fahrenheit?"

MH didn't specify--another reason his attempted point was so ill formed. The graphs I posted are F and clearly show that 9F (at least) is near or well within possible projected temps by the end of the century. But in any case the main claim is that there are IPCC projections that show 9 C temperature rises in a little over a century from now. That is simply a fact. Why anyone would find such a fact laughable is beyond me.

The charts I posted had Celcius all through them. 

There are no IPCC projections showing 9 C warming.  The top end of the uncertainy range for RCP8.5 is about 6 degrees.  The 9 degrees is something that ASLR just made up.  He multiplied the median climate sensitivity of 3 by 1.5 to be equivelant to a high climate sensitivity of 4.5.  This ignores the fact that equilibrium climate sensitivity is not relevant to projections over the next century, but rather transit climate sensitivity, as there are significant issue of time lags.  If climate sensitivity is higher, it is likely that time lags are also longer, otherwise we would have seen a greater amount of warming over the last century.

MH,

Either you need to try to stay focused, or no one is going to take you seriously.  Again, the title of this thread set-up by wili is: "IPCC possible scenario: 9 C over next century or so".  As the attached image that wili provided in his first post the 9 C mean surface temperature rise (with an ECS of 4.5 C) does not happen until closer to 2140 (thus the "... or so") for RCP 8.5, while a mean surface temperature rise of 9 F (5 C) occurs near 2100 for RCP 6.  wili never said which RCP scenario he is concerned about; however, I have said that I am concerned about RCP 8.5, which for an ECS of 4.5 C results in a mean surface temperature rise of nearly 7 C by 2100.

Furthermore, I never estimated a value of 4.5 C by multiplying 3 C by 1.5; however, I did provide a large number of peer reviewed papers that had values of ECS both above and below 4.5 C, and you said that you could accept that it is plausible that ECS might be 4.5 C.  No one can provide a definite forecast of future warming, and the purpose of this thread is to explore the upper end of plausible scenarios.
« Last Edit: October 25, 2014, 07:00:53 PM by AbruptSLR »
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #119 on: October 25, 2014, 08:02:22 AM »
There are plenty of reasons why the future warming rate may increase above the current slower than expected rate.  However we are currently sitting at the bottom end of projections and a claim that we will be above the top end of ICCP projections is extraordinary, and requires strong evidence. 

On Durack, as I've pointed out on the thread on that paper it is not a given that sensitivity be increased due to this result.  Climate sensitivity would likely be increased if the total top of atmosphere radiative balance was increased.  When calculating the global heat budget Church et al take the measurement of top of atmosphere as a given and then calculate aerosol forcing as the residual amount required to balance the other measured budget items such as ocean heat uptake.  If the Church et al analysis was repeated with a higher ocean heat uptake this would result in a lesser aerosol cooling factor, which would imply that Durack implies a lower climate sensitivity not higher.

MH,
You (of all people) should realize that with regard to climate change projections (due to the chaotic nature of the ocean and atmosphere) that no "proof" is possible; however, given the negative PDO phase that we have just left, I believe that it is much more likely that by 2025 that we be following an RCP 8.5 surface temperature scenario than a RCP 2.6 scenario.

Regarding the implications of the Durack et al (2014) paper, I concur that it does not "prove" anything; however, I believe that your interpretation of the possible implications of this paper is confused.
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #120 on: October 25, 2014, 08:13:46 AM »
While AOGCMs/GCMS, & ESMS, do not use climate sensitivity parameters directly, still calculating such parameters are convenient for discussions, so I provide the following equations:
The mean global surface temperature change (deltaT), can be determined by the equation, for a given radiative forcing change (deltaF):

deltaF = (lambda) (deltaT) + deltaQ

Where:       lambda = the effective climate feedback parameter (in W m-2C-1), and
      deltaQ  =  the imbalance between the climate forcing and the response (in W m-2), which is dominated by ocean influence and thus is generally referred to as the ocean heat uptake (and is currently estimated to be 0.85 +/- 0.15 W m-2 and is currently dominated by the ocean heat uptake.

It is helpful to note that this common equation is linear and therefore is only an approximation of non-linear relationships.  Also, it is important to note that there is considerable uncertainty about what is the response timeframe for all of the feedback factors.  Therefore, it can be confusing as to which mechanisms contribute directly to ECS and which additional mechanism only contribute to ESS; as mechanisms that are traditionally considered to be "slow response"  many be activated to make a significant contribution to global warming this century.
« Last Edit: October 26, 2014, 04:18:33 PM by AbruptSLR »
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #121 on: October 26, 2014, 04:17:13 PM »
It is helpful to remember that climate sensitivity changes with time.  Therefore, even if ECS turns-out to be 3 C today, by the end of the century (say following RCP 8.5) the effective ECS could be considerable higher as positive feedback factors such as the following (partial list) possibly become more active:

a) If La Nina's become less frequent and if more frequent El Nino's (due to a positive PDO phase) vent sequestered heat from the ocean;
b) As China accelerated the cleans-up its aerosol emissions beyond what is assumed in RCP 8.5;
c) As the North Pacific comes in sync with the North Atlantic in order to accelerate Arctic amplification;
d) As the permafrost (both on land and underwater) degradation accelerates;
e) As ocean acidification suppresses the production of dimethylsulphide (DMS);
f) As Northern Hemisphere, NH, albedo increases due to reduced Arctic Sea Ice extent, reduced NH snow cover, and increased shrub growth in the tundra;
g) As the Arctic atmospheric OH supply diminishes thus increasing the GWP of regional atmospheric CH4;
h) As the frequency and extent of wildfires increases;
i) As the size of plankton diminishes, thus making it more difficult for the oceans to sequester CO₂;
j) As increasing upwelling (particularly in the Southern Ocean) increases CO₂ venting from the oceans;
k) As heat stress decreases the ability of terrestrial plants to sequester CO₂;
l) As world populations continue to grow and demand for energy, more meat and more material wealth;
m) As the amount of volatile organic compounds (VOCs) emitted by forests decrease (due to climate change related stress).
n) As the Southern Ocean vents more CO₂.
o) As Soil-organic-carbon (SOC) processes release more CO₂.
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wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #122 on: October 26, 2014, 06:35:26 PM »
Good list. Note also that the recent discovery that Methanoflorens, a microbe that produces methane, is very abundant in thawing permafrost, suggests that a much higher portion of ghgs produced by permafrost as it thaws will be in the form of methane rather than CO2.

http://phys.org/news/2014-10-microbe-key-player-climate.html

 The major model that included permafrost in its forecast assumed 0% methane.

(McDougal et al. 20120 http://www.skepticalscience.com/Macdougall.html)

That model showed that, even if all further human ghg emissions were stopped in 2013, CO2 levels would remain the same or rise considerably over the next two centuries (unless an unrealistically low climate sensitivity was assumed; see figure 3a in the article just linked).

So, with more of the permafrost coming as methane, a much stronger GHG, we can expect even higher temperatures with faster feedbacks from other carbon sources cranking up atmospheric levels even higher over the next two centuries, at least--and that even if we had stopped all further emissions back in 2013.

In other words, we have to move with all haste to a strongly carbon negative global economy, whatever that looks like and whatever we have to do to get there, if we want to have anything like a livable world to pass on to future generations (or even to enjoy in our own dotage).
« Last Edit: October 26, 2014, 06:43:28 PM by wili »
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #123 on: October 26, 2014, 06:50:04 PM »
The major model that included permafrost in its forecast assumed 0% methane.
Tell me why I'm not surprised. I assume 0% integrity from these quarters.
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wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #124 on: October 26, 2014, 07:27:15 PM »
I see what you mean. But look, at least they were trying to include some feedback from permafrost carbon. The standard models were just ignoring that whole huge feedback altogether.

At the time, the standard analysis was that methane would only be about 3% of such emissions, so assuming 0% may have seemed more of a issue of rounding off a very low number to zero for simplicity sake.

But given the much higher global warming potential (GWP) of methane, one would have hoped that they would have at least attempted to include some of this. Again, though, models are intended to be just that--models: only partial representations of the true complex reality.

Other reasons that the study was "optimistic" according to the piece from SkS sited above:

>>their model assumes only purely thermal degradation of the permafrost. Physical erosion, for example at coastlines, is not considered.

>>Their model accounts only for permafrost down to a depth of 3.5 metres and there is plenty of carbon stored below those depths that was excluded from their modelling.[In some cases, permafrost is about a mile deep.]

>>Finally, this study does not consider any contribution of methane from methane hydrates, either from under permafrost or under ice sheets, nor from fossil methane currently trapped under an impermeable seal of continuous permafrost.

The last two probably won't kick in for decades if not centuries (though those blow holes recently discovered should give us all pause wrt such things), but they should surely be ultimately included in any more complete model of likely carbon feedbacks from the region. They would likely push the effects of these feedbacks out many centuries and also would add to not only the slope but the upward curve of future atmospheric GHG figures and forcing levels.

"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #125 on: October 26, 2014, 11:03:31 PM »
In the way of additional background on the origin of the RCP scenarios, the attached image shows the trend in radiative forcing used in generating RCP scenarios, from van Vuuren et.al. (2011).  The middle panel of the attached image shows that the RCP 8.5 scenarios were developed to produce projections that were about at the 90% level of the published projections available in 2009 (see reference), and not to produce 95% CL of the actual upper bound global-mean temperature projection.

Van Vuuren, D.P., Edmonds, J., Kainuma, M., Riahi, K., Thomson, A., Hibbard, K., Hurtt, G.C., Kram, T., Krey, V., Lamarque, J-F., Masui, T., Meinshausen, M., Nakicenovic, N., Smith, S.J., and Rose, S.K.; "The representative concentration pathways: an overview"; Climatic Change (2011) 109:5-31, doi: 10.1007/s10584-011-0148-z.

See also:
http://www.skepticalscience.com/rcp.php?t=3

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Michael Hauber

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #126 on: October 27, 2014, 10:20:48 AM »

Furthermore, I never estimated a value of 4.5 C by multiplying 3 C by 1.5; however, I did provide a large number of peer reviewed papers that had values of ECS both above and below 4.5 C, and you said that you could accept that it is plausible that ECS might be 4.5 C.  No one can provide a definite forecast of future warming, and the purpose of this thread is to explore the upper end of plausible scenarios.

So where did the 9 degree warming come from?  Did you just draw a line randomly where you thought it seemed right?  Or did you decide that because 3x1.5 is 4.5 that you'd multiply the IPCC warming scenario by 1.5?

The upper end as presented by the IPCC scenarios is about 6 degrees.  I provided reference for this earlier.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #127 on: October 27, 2014, 10:22:00 AM »
MH,
You (of all people) should realize that with regard to climate change projections (due to the chaotic nature of the ocean and atmosphere) that no "proof" is possible; however, given the negative PDO phase that we have just left, I believe that it is much more likely that by 2025 that we be following an RCP 8.5 surface temperature scenario than a RCP 2.6 scenario.

Regarding the implications of the Durack et al (2014) paper, I concur that it does not "prove" anything; however, I believe that your interpretation of the possible implications of this paper is confused.

So you are now trying the 'if I keep saying I'm right you are wrong line often enough no one will notice I have no argument' tactic.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #128 on: October 27, 2014, 10:29:07 AM »
European Union now has an agreement to cut emissions by 40% by 2030.  Climate Progress

Engage Troll mode:  That must be the final nail in the RCP 8.5 coffin :P

I'm rather amazed that they would actually agree to such a thing before any agreement with China or America is finalised.

Climate change:  Prepare for the worst, hope for the best, expect the middle.

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #129 on: October 27, 2014, 10:34:35 AM »
The only half way reasonable way I've ever heard for warming above what the IPCC project is through a methane permafrost or hydrate runaway feedback.  I found a skeptical science article about this issue, and the implications are that a fast runaway (roughly a century or faster) feedback is highly unlikely.  I still have serious concerns about what may be possible on longer time scales.  Details in the methane thread.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #130 on: October 27, 2014, 04:00:50 PM »

Engage Troll mode:  That must be the final nail in the RCP 8.5 coffin :P


As MH has admitted that he has a "Troll Mode", I ask other readers to let me know if they find it valuable for me to continue responding to his "Trollish Posts", or if it is better that I stop "Feeding this Trollish Behavior".
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #131 on: October 27, 2014, 05:12:59 PM »
The linked article from The Carbon Brief, indicates that the IPCC's range of climate sensitivity values includes values from three types of methods: (a) paleo, (b) observation in the last century, and (c) from climate models, and that the IPCC does not evaluate the values from these different sources for accuracy, but merely lumps them all together (ie dumbs it down) so long as there is a body of published literature (that denialists can manipulate).  It is my position that the output from the most high-performance Earth System Models, ESM, represent the best science available and should be given the most attention, and such climate models support sensitivity values at the higher end (ie 4 C to 4.5 C) for ECS.

Unfortunately, the article indicates that the IPCC is not going to change its range of ECS values any time soon, so we will need to wait many years before the best science available (high-performance ESM output) is used for policy making:

http://www.carbonbrief.org/blog/2014/09/your-questions-on-climate-sensitivity-answered/

Extract: "One method looks at how earth responded to natural greenhouse gas changes in its geological past. Another matches global surface temperatures with greenhouse gas concentrations and other forcings over the last century or so, to try and work out sensitivity from how the planet is responding - what's known as the 'energy budget model' approach. The third uses climate models to predict the theoretical effect of a doubling of carbon dioxide based on scientists' understanding of how different elements of the climate system interact.


Climate sensitivity estimates using climate models support the higher end of the IPCC's likely range. Such estimates are rooted in the behaviour of known physical processes but contain large uncertainties, such as the interaction of aerosols with clouds.

The IPCC considers all the different ways of calculating climate sensitivity, without making a value judgment about which is best. So as long as there is a body of literature supporting both ends of the likely range, it won't be revising it any time soon."
« Last Edit: October 27, 2014, 06:32:18 PM by AbruptSLR »
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Laurent

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #132 on: October 27, 2014, 05:14:56 PM »
Don't feed the trolls AbruptSLR, but yes feed us with nice informations ! Thanks for your job.

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #133 on: October 27, 2014, 06:30:06 PM »
Don't feed the trolls AbruptSLR, but yes feed us with nice informations ! Thanks for your job.


Laurent,

Per your request:

Table 12.4 of the linked AR5 Working Group I "Chapter 12: Long-term Climate Change: Projections, Commitments and Irreversibility" in Section: 12.5.5 Potentially Abrupt or Irreversible Changes, sub-section: 12.5.5.1 Introduction; contains the following extract about the probability of a collapse of the West Antarctic Ice Sheet, this century, as a component of irreversible long-term climate change.

http://www.climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter12.pdf

Extract:
Change in climate    Potentially    Irreversibility if     Projected likelihood of 21st century change in
system component   abrupt           forcing reversed     scenarios considered

Ice sheet collapse        No              Irreversible for          Exceptionally unlikely that either
                                                        Millennia                 Greenland or West Antarctic Ice
                                                                                     sheets will suffer near-complete
                                                                                     disintegration (high confidence)


However, in May 2014 Eric Rignot (one of the world's top ice sheet experts), wrote the following linked article about the potential collapse of the West Antarctic Ice Sheet, WAIS, that contains the following extract.

http://www.theguardian.com/commentisfree/2014/may/17/climate-change-antarctica-glaciers-melting-global-warming-nasa?commentpage=4

Extract: "We announced that we had collected enough observations to conclude that the retreat of ice in the Amundsen sea sector of West Antarctica was unstoppable, with major consequences – it will mean that sea levels will rise one metre worldwide. What's more, its disappearance will likely trigger the collapse of the rest of the West Antarctic ice sheet, which comes with a sea level rise of between three and five metres. Such an event will displace millions of people worldwide.

Two centuries – if that is what it takes – may seem like a long time, but there is no red button to stop this process."

The point of this post is that while the IPCC process can indicate a "High Confidence" that it is "Exceptionally Unlikely" that the WAIS will suffer near-complete collapse this century; however, this process does not provide any guarantees at all that a few months later, research from one of the top experts in the world on this subject will show that the collapse of the WAIS is unstoppable and that it could occur in less than 200 years.  Therefore, do not be surprised when in a few years time research shows that ECS is now between 4 C and 4.5 C, and that the effective ECS is increasing as more and more feedback factors are engaged with increased global warming.
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Laurent

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #134 on: October 27, 2014, 07:10:57 PM »
There was that graph in the link you provided AbruptSLR.

Showing probable ECS up to 9°C... ??? What does that really mean, how can we compare with reality ? There was a climate scientist in a talk that was saying at 4, 5°c we (French) are toasted like the people of Tombouctou.

Laurent

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #135 on: October 27, 2014, 07:28:33 PM »
Also from a commenter in one of your link :
Researchers Find 3-million-year-old Landscape Beneath Greenland Ice Sheet
http://www.nasa.gov/content/goddard/researchers-find-3-million-year-old-landscape-beneath-greenland-ice-sheet/#.VE6EtFHWTlc

« Last Edit: October 27, 2014, 07:38:31 PM by Laurent »

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #136 on: October 27, 2014, 07:35:24 PM »
Laurent,

I am a bit distracted at the moment, so I will give you a quick response. 

First, notice in the table that you posted (in Reply #134) the model results only include outs from AOGCMs (no high-performance ESM outputs are included, and ESM outputs indicate higher values of effective climate sensitivity, ie 4 C to 6 C).

Second, you should review the linked paper  that shows that climate sensitivity is likely higher than assumed in most prior AOGCM projections:

http://onlinelibrary.wiley.com/doi/10.1002/qj.2165/abstract;jsessionid=ED7BA33BAD69F5B1E7BCFD85EAC3DF89.d02t01

Previdi, M., B.G. Liepert, D. Peteet, J. Hansen, D.J. Beerling, A.J. Broccoli, S. Frolking, J.N. Galloway, M. Heimann, C. Le Quéré, S. Levitus, and V. Ramaswamy, 2013: Climate sensitivity in the Anthropocene. Q. J. R. Meteorol. Soc., 139, 1121-1131, doi:10.1002/qj.2165.
"Climate sensitivity in its most basic form is defined as the equilibrium change in global surface temperature that occurs in response to a climate forcing, or externally imposed perturbation of the planetary energy balance. Within this general definition, several specific forms of climate sensitivity exist that differ in terms of the types of climate feedbacks they include. Based on evidence from Earth's history, we suggest here that the relevant form of climate sensitivity in the Anthropocene (e.g. from which to base future greenhouse gas (GHG) stabilization targets) is the Earth system sensitivity including fast feedbacks from changes in water vapour, natural aerosols, clouds and sea ice, slower surface albedo feedbacks from changes in continental ice sheets and vegetation, and climate–GHG feedbacks from changes in natural (land and ocean) carbon sinks. Traditionally, only fast feedbacks have been considered (with the other feedbacks either ignored or treated as forcing), which has led to estimates of the climate sensitivity for doubled CO2 concentrations of about 3°C. The 2 X CO2 Earth system sensitivity is higher than this, being ∼4-6°C if the ice sheet/vegetation albedo feedback is included in addition to the fast feedbacks, and higher still if climate–GHG feedbacks are also included. The inclusion of climate–GHG feedbacks due to changes in the natural carbon sinks has the advantage of more directly linking anthropogenic GHG emissions with the ensuing global temperature increase, thus providing a truer indication of the climate sensitivity to human perturbations. The Earth system climate sensitivity is difficult to quantify due to the lack of palaeo-analogues for the present-day anthropogenic forcing, and the fact that ice sheet and climate–GHG feedbacks have yet to become globally significant in the Anthropocene. Furthermore, current models are unable to adequately simulate the physics of ice sheet decay and certain aspects of the natural carbon and nitrogen cycles. Obtaining quantitative estimates of the Earth system sensitivity is therefore a high priority for future work."

edit: As to how you compare the implications of these climate sensitivity values to reality, you can look at the graph in the first post that wili made (Reply #1) and pick which scenario you want to assume and read the increase in mean global surface temperature off of the plot.
« Last Edit: October 27, 2014, 07:59:24 PM by AbruptSLR »
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Laurent

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #137 on: October 27, 2014, 07:58:36 PM »
There is also that study about the Antarctic :
Mid-Miocene Warming Greened Antarctica
http://www.sci-news.com/othersciences/paleoclimatology/article00417.html
http://www.livescience.com/14803-antarctica-vegetation-vanished-pollen-glacial-history.html

It seems the Antarctic melted 16 Million years ago...at 4°C of Global temperature ? That does mean we are in for a total melting of antartica with an ECS of 4.5 (and more)...More than 70 meters of SLR...???

viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #138 on: October 27, 2014, 09:38:05 PM »


Discuss...

wili, can you give us the IPCC link/url for this 'IPCC possible scenario'? Thanks.

BTW, I found it myself, using Google's Search By Image function:
http://skepticalscience.com/climate-best-to-worst-case-scenarios.html
« Last Edit: October 28, 2014, 01:56:29 AM by viddaloo »
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #139 on: October 27, 2014, 10:04:36 PM »
The linked Skeptical Science article from June 2014 contains the attached image and the following extract indicating that for the Large Ensemble (LE) Community Project, it was not difficult to use RCP 8.5, and ECS of 4.1, and then to match the observed NOAA decadal mean global surface temperature trend (including forecasting the faux hiatus):

http://www.skepticalscience.com/challenges-constraining-climate-sensitivity.html

Extract: "The NCAR CESM1-CAM5 Large Ensemble Community Project provides a unique framework for understanding the role of internal variability in obscuring forced changes. It currently consists of 28 ensemble members in simulations of the historical record (1920-2005) and future projections (2006-2080) based on RCP8.5 forcing.

At 4.1 C, the ECS of the CESM1-CAM5 is higher than for most GCMs. Nonetheless, decadal trends from the model track quite closely with those derived from NOAA-NCDC observations (red line), with the model mean decadal trend (thick black line) skirting above and below observed trends about evenly since 1920. In several instances, decadal trends in observations have been at or beyond the LE ensemble range including intervals of exceptional observed warming (1945, 1960, 1980) and cooling (1948, 2009). The extent to which these frequent departures from the LE reflect errors in observations, insufficient ensemble size, or biases in model internal variability remains unknown. Nonetheless, there is no clear evidence of the model sensitivity being systematically biased high. Also noteworthy is the fact that the LE suggests that due to forcing, as indicated by the ensemble mean, certain decades including the 2000s are predisposed to a reduced rate of surface warming."



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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #140 on: October 27, 2014, 10:25:54 PM »
If some readers want to know how to fight against climate change, then I believe that the most effective way is to get 51% of the voters to support a carbon fee – dividend plan.  The free pdf found at the following link describes in detail what I mean by a carbon fee – dividend plan applied to the USA.

http://citizensclimatelobby.org/wp-content/uploads/2014/06/REMI-carbon-tax-report-62141.pdf

Any country adopting such a plan could impose tariffs on countries who do not impose a comparable plan; which, should stop other countries from cheating.

Furthermore, the following link indicates that George Shultz, Greg Mankiw, Romney's Economics Advisor, and Art Laffer, a member of President Reagan's Economic Policy Advisory Board, all agree that the F&D plan is not a tax (because the government does not keep the money, see the attached image of how much money each month an average family would be given under the plan); and they all support the F&D plan; and the plan was one of the finalists in the “U.S. Carbon Price” category of MIT’s Climate CoLab contest:

http://www.normantranscript.com/opinion/article_7e3f4b94-4e42-11e4-a576-378afba4ca8b.html


"What do these three well-known Republican economists have in common?
 
1. George Shultz, President Reagan's Secretary of the Treasury, and Economics Professor at MIT before Reagan tapped him for public service.
 

2. Greg Mankiw, Romney's Economics Advisor, Chairman and Professor of Economics at Harvard University.
 
3. Art Laffer, a member of President Reagan's Economic Policy Advisory Board for eight years with Economics degrees from Yale and Stanford.
 
Answer: All three actively support the Carbon Fee and Dividend proposal by CCL, the Citizens Climate Lobby.
 
Is this idea a tax?
 
George Shultz says, "It's not a tax if the government doesn't keep the money.""

If this F&D plan gains enough bipartisan political support, it might be able to make a difference.

See also:
http://climatecolab.org/web/guest/plans/-/plans/contestId/1300404/planId/2802
« Last Edit: October 27, 2014, 10:45:54 PM by AbruptSLR »
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wili

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #141 on: October 27, 2014, 10:37:26 PM »
Thanks for tracking down those links, ASLR.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #142 on: October 27, 2014, 10:47:30 PM »
European Union now has an agreement to cut emissions by 40% by 2030.  Climate Progress

Engage Troll mode:  That must be the final nail in the RCP 8.5 coffin :P

I'm rather amazed that they would actually agree to such a thing before any agreement with China or America is finalised.


Well, it's not quite as ambitious at it might seem:

They already had an agreement for a 20% reduction below 1990 levels with legally binding stipulations for each country. This agreement is more or less a continuation of that one, with another 20% reduction, but NO legally binding targets for any specific country that I can see, just blanketed as a EU-wide target. This brings up the specter of enforceability.

In addition, the target largely relies on energy efficiency improvements (27% improvement from now until 2030), whereas the renewable energy target only increases from the current 14% to 27%. In essence, it relies more on picking the low hanging fruit (efficiency) to get to the 40% mark, which is more politically palatable. It focused less on the renewable energy sector, which encountered some stiff political resistance. This makes it harder to get to those all-important 2050 goals, because the next section of critical cuts will have to be made mostly on renewables (efficiency gains will only go so far).

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #143 on: October 27, 2014, 10:55:01 PM »
If some readers want to know how to fight against climate change, then I believe that the most effective way is to get 51% of the voters to support a carbon fee – dividend plan.

While gathering 51% support among ordinary Americans may be hard, the "tiny detail" that will sink your boat is the establishment of a non–corrupt and non–compromized true democracy in North America, in which your 51% majority may be utilized. Merely having a 51% majority that feels the same way gets you nowhere without the latter.
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AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #144 on: October 27, 2014, 11:10:26 PM »
If some readers want to know how to fight against climate change, then I believe that the most effective way is to get 51% of the voters to support a carbon fee – dividend plan.

While gathering 51% support among ordinary Americans may be hard, the "tiny detail" that will sink your boat is the establishment of a non–corrupt and non–compromized true democracy in North America, in which your 51% majority may be utilized. Merely having a 51% majority that feels the same way gets you nowhere without the latter.

viddaloo,

While I respect your opinion, as climate change becomes worse (faster than many think) it will become easier to stigmatize the corrupting parties (eg lobbyists, etc.), as easily as it is to stigmatize ISIL (ISIS), or ebola, now.

If we stay on our current BAU pathway, then sometime after 2050 several billion people will die; which is quite a stigma (the largest mass murders in history, not to mention tens of trillions of dollars of economic losses) to pin on corrupting influences.

For periods of decades corrupting influences are quite afraid of public opinion (until they have time to rig the new system) as happened in many past revolutions including the American Revolution.

Best,
ASLR
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viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #145 on: October 28, 2014, 12:08:23 AM »
You may have the nails you need, but you won't have the hammer.

As you (and I) focus on the ice and the Cryosphere, it's easy to imagine all other things to be in full working order. But they're not. In fact, the more you look, the more things you'll find to be in everything but full working order. This goes for society and the alleged democracy as well.

Once you (or I) decide we need a 51% majority in order to fix the Cryosphere, work must then begin to establish a true democracy bottom–up, from the grassroots and local neighborhoods. Just assuming there is such a thing as democracy out there, already, is a bit of a stretch, but understandable, if one is entrenched in natural sciences.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #146 on: October 28, 2014, 02:41:08 AM »
If we stay on our current BAU pathway, then sometime after 2050 several billion people will die; which is quite a stigma (the largest mass murders in history, not to mention tens of trillions of dollars of economic losses) to pin on corrupting influences.

Trouble is by the time things are bad enough, good chance committed change in the system is enough to take everything down. We might already be past that point even now, we don't really know for sure, do we?

AbruptSLR

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #147 on: October 28, 2014, 02:56:54 AM »
If we stay on our current BAU pathway, then sometime after 2050 several billion people will die; which is quite a stigma (the largest mass murders in history, not to mention tens of trillions of dollars of economic losses) to pin on corrupting influences.

Trouble is by the time things are bad enough, good chance committed change in the system is enough to take everything down. We might already be past that point even now, we don't really know for sure, do we?

I only have time for a short reply; however, when I said "fight" climate change I did not mean "cure" climate change.  Of course we are already accumulating damage now, and the longer we delay a real fight (as in a progressive carbon fee & dividend) then the worse consequence we will experience.  I admit that currently 51% of the representatives of the people are not sufficiently scared to vote for a fee & dividend plan; however, I suspect that as we enter a period of combined positive PDO and soon (10-years) a warming phase of the AMO, that by 2030 there will be enough climate consequences to stigmatize the worse players so that some real fighting can begin (of course I would prefer that a fee & dividend plan pass the US congress in 2016, but I doubt that we will be that lucky).  If we don't envision solutions we are likely to drift further down the BAU pathway.

Best.
ASLR
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viddaloo

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Re: IPCC possible scenario: 9 C over next century or so
« Reply #148 on: October 28, 2014, 04:13:11 AM »
If we don't envision solutions we are likely to drift further down the BAU pathway.

I totally agree with that statement. And let me add that the only reason I mention the 'democracy problem' is that if our plan was to wait 10 years for there to be a 51% majority, and only then found out there was no semblance of democracy, then we would surely fail, miserably.

Therefore our plan must be something different. Something that might actually work.
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Re: IPCC possible scenario: 9 C over next century or so
« Reply #149 on: October 28, 2014, 11:12:35 AM »
The linked Skeptical Science article from June 2014 contains the attached image and the following extract indicating that for the Large Ensemble (LE) Community Project, it was not difficult to use RCP 8.5, and ECS of 4.1, and then to match the observed NOAA decadal mean global surface temperature trend (including forecasting the faux hiatus):

http://www.skepticalscience.com/challenges-constraining-climate-sensitivity.html

Extract: "The NCAR CESM1-CAM5 Large Ensemble Community Project provides a unique framework for understanding the role of internal variability in obscuring forced changes. It currently consists of 28 ensemble members in simulations of the historical record (1920-2005) and future projections (2006-2080) based on RCP8.5 forcing.

At 4.1 C, the ECS of the CESM1-CAM5 is higher than for most GCMs. Nonetheless, decadal trends from the model track quite closely with those derived from NOAA-NCDC observations (red line), with the model mean decadal trend (thick black line) skirting above and below observed trends about evenly since 1920. In several instances, decadal trends in observations have been at or beyond the LE ensemble range including intervals of exceptional observed warming (1945, 1960, 1980) and cooling (1948, 2009). The extent to which these frequent departures from the LE reflect errors in observations, insufficient ensemble size, or biases in model internal variability remains unknown. Nonetheless, there is no clear evidence of the model sensitivity being systematically biased high. Also noteworthy is the fact that the LE suggests that due to forcing, as indicated by the ensemble mean, certain decades including the 2000s are predisposed to a reduced rate of surface warming."


I apologise for assuming the 9 degree chart was was your creation - I did not realise it was created by Skeptical Science who are usually a high quality and reputable source of information.  However in this I think they are clearly wrong.

To repeat the point for the umpteemth time.  I accept there is a possibility the climate sensitivity is as high as 4.5.  However my point that is being totally ignored is that there is a trade off where high sensitivity models have longer lags, otherwise they don't match the temperature history to date.  Note that for this modelling scenario the decadal trends are all less than 0.6/decade, and by eyeball guess average something like 0.45.  So the warming projected by this model is clearly less than 6 degrees for the next 100 years.  Add that to a current warming amount of 1 degree, and we are clearly well short of the 9 degrees in the Skeptical Science chart of what 4.5 degree sensitivity would look like in 2100.  The total warming looks like it would be closer to the 6 degree maximum which is what I've claimed is the true IPCC worst case scenario as the IPCC directly state eg here  (note IPCC use a different base line so to be comparable to the Skeptical science chart should be moved up roughly 0.5 to 1 degree C).
Climate change:  Prepare for the worst, hope for the best, expect the middle.