AVOIDing dangerous climate change. Can Global Warming be Limited to Two Degrees?

[Jim Hunt]

I attended a meeting of Transition Exeter yesterday evening, which was interesting for a variety of reasons. Here's my preliminary report:

http://econnexus.org/can-global-warming-be-limited-to-two-degrees/

Apart from the obvious conclusion that "There's not a snowball's chance in hell!" it's interesting (to me at least) that the Met Office seem to be happy to put on that sort of presentation to a small group in Exeter Community Centre.

Afterwards I mentioned to the man from the Met that I'm an "Arctic sea ice nutter!". He suggested I should stop worrying about permafrost and instead start worrying about things like the Sudd, and the Amazonian rainforest falling down if we don't cut it down first.

[TerryM]

Jim
As I'm unable to stop worrying about permafrost I suppose I'm now required to add Sudd to my list of near term calamities.[size=78%]
Terry[/size]

[AbruptSLR]

Jim,

My biggest issue about this topic is that the so call process-based scientific community (eg AR5) recognize the validity of the 2 degree scenarios (which as you say do not have a snowball chance in hell) and include RCP 2.6 in all of their probability forecasts; while rejecting as unscientific any factors/mechanisms that would result in radiative forcing scenarios greater than RCP 8.5.

Why is it scientific to accept the 2 degree scenarios; but unscientific to consider factors/mechanisms that have been proven to be the case just months after AR5 was released including: (a) Sherwood et al (2014) showing the mean equilibrium climate sensitivity, ecs, is probably closed to 4.5 degrees C instead of 3.0 degrees C; (b) the methane concentration in the atmosphere continues to increase, and that the chemical signature of this increase in methane indicates an organic origin, this increase is most likely due to degradation of the permafrost; while all of the RCP scenarios ignored almost all of the methane emissions from the permafrost; (c) as we enter a positive PDO phase the oceans will release into the atmosphere a meaningful portion of the heat that it sequestered during the past 15-year negative PDO phase; while none of the IPCC GCM projections can account for such PDO phases and (d) the recently reported decrease in Arctic albedo as compared to AR5 assumptions.

It seems to me that the process-based scientific establishment is blind to its own biases, while happy to ignore threats that are proving to be true as soon as we have time and money to study them properly.  Possibly if we get a Super El Nino in the 2014-2015 timeframe and the mean global temperatures shoot-up, society will start to take these threats seriously, but I am not holding my breath.

Best,
ASLR



Sherwood, S.C., Bony, S., and Dufresne, J.D. (2014), "Spread in model climate sensitivity traced to atmospheric convective mixing", Nature; 505, pp 37–42; doi:10.1038/nature12829

[Jim Hunt]

ASLR - Even if you consider that AVOID understates the risks, consider also what use policymakers and the mass media have made of the evidence they have been presented with thus far. The bullet points in the "glossy brochures" from DECC that I refer to do at least include:

• Arctic sea-ice
• Sea-level rise and melting of the great ice-sheets
• Carbon release from permafrost and ocean sediments
• Ocean circulation
• Acidification of the oceans
• Tropical forest dieback

Sir Brian Hoskins has been in the news recently:

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/feb/27/bbc-false-balance-fox-news-global-warming

He's also the first of the delegates at the AVOID symposium last year to offer an opinion in this Met Office video:



Sir Brian reckons that if AVOID were an animal it would be a wise owl. What do you suppose Nigel Lawson's verdict would be, or the BBC's for that matter?

[Apocalypse4Real]

Jim,

Thanks for the thread and the report. We hit above an hourly 400 ppm on 022614  at MLO.

I am working on a post that uses the CO2 modeling and estimates for CO2/CO2e modeling that I think will help the no 2C argument - and hope to get that up this weekend.

A4R.

[AbruptSLR]

Jim & A4R,

I very much appreciate this thread & the information provided, and for the record I generally side with James Hansen who supports limiting mean global temperature rise above pre-industrial levels of 1 degree C (because I believe that the climate is more sensitivity than most people, including most scientists are willing to admit).  With that said, almost all policy makers refuse to consider a 1 degree C limit, because achieving it would hurt too much. 

Now when you consider the attached graph from AVOID showing pathways ways to achieve a 50% chance of limiting mean global temperature rise to 2 degrees C; to be honest one would need to point out to policy makers and the public that to achieve this goal would require a worldwide effort, from all governments simultaneously, comparable to the worldwide effort made during World War II, for at least the next 50-years continuously (which as you point out is as likely as a snowball surviving in hell).

While I generally admire scientist greatly, and I am sure that the process-based science reports like AVOID are well intended, nevertheless, "The road to hell is paved with good intentions".  I believe that when government agencies say that a 2 degrees C limit is still achievable, many please think to themselves: "Good, the government has this situation under control, so I can go ahead and enjoy a fossil fuel rich life style, because the situation is under control."

I may be jaded, but I believe that the only way to get the policy makers, and the public, to take the strong measures needed to protect society, is the path that James Hansen is taking, which is not to sugar coat the truth, and to let people know that abrupt climate change (including abrupt sea level rise) is coming this century, because even if a miracle technology is invented it would take many decades to implement such a miracle on a worldwide basis; and by that time abrupt consequences will be upon us.

I realize that James Hansen has been communicating his message since the early 1980's and we are still on a pathway exceeding the RCP 8.5 scenario; but unless we can convince policy makers that what is coming is so un-naturally extreme (massive extinctions, massive food disruption, abrupt sea level rise) that it is indeed far worse than the terrorist threat (as John Kerry has pointed out); then I believe that efforts such as the AVOID effort will produce about as much impact as the Kyoto Protocol has had.

While speaking truth to power can be dangerous (as Hansen lost his job), I believe that it is necessary, and in my next post here I will try to present little bit of evidence about how serious our current situation really is.

Best,
ASLR

[Apocalypse4Real]

The MLO CO2 hourly readings crossed 400 ppm on February 26, 2014. I have posted on this today:

See: http://a4rglobalmethanetracking.blogspot.com/

[AbruptSLR]

The references in the list at the end of this post discuss positive feedback mechanisms (and related topics), that in my opinion, were not adequately accounted for in IPCC's AR5 (nor in the AVOID model projections). 

While I do not have time to do any of this findings justice; nevertheless, I will say that to whatever RCP scenario that your value system allows you to accept as realistic, you need to add the following factors that were left out of AR5 (and AVOID) projections:

(a) Sherwood et al (2014) and Fasullo & Trenberth (2012) show that the most likely value for ECS is about 4.5 degrees C instead of the assumed mean value of 3 degrees C; therefore, you should multiply the old projections by a factor of about 1.5, due to the low amount of cloud cover near the equator.
(b) Pistone et al. (2014) shows that the decrease in Arctic albedo (including land snow, sea ice and black carbon effects) beyond that previously assumed results in additional radiative forcing equal to ¼ of the CO₂ in the atmosphere.
(c) Schuur & Abbott (2011) shows that the permafrost emits about 2% of its carbon emissions as methane instead of as CO₂ (as assumed by AVOID), and as over a one hundred year period, methane has a global warming potential at least 35 times that of CO₂, this means at least a 70% error in the carbon emissions from the permafrost degradation.  See also Monday et al. (2014) and Isaksen et al. (2011).
(d) Cowtan & Way (2013); England et al. (2014); Santer et al (2014); and Rosenfeld (2014); all provide solid evidence that the current mean global temperature has been masked by such causes as: limited data; the negative phase of the PDO cycle; volcanoes, and aerosols, respectively.  Furthermore, once corrections are applied to the GCM projections to account for these masking mechanisms, one will find that the ECS is actually higher than previously assumed, which supports my points (a), (b) and (c).
(e) Hansen et al. (2013) and Previdi (2013) show that the inclusion of slow-response feedback mechanisms can cause Earth Systems Sensitivity to be as high as 6 degrees C (while work such as Pistone et al. (2014) shows that the "slow response" feedback mechanisms are occurring very quickly).

I do not have time to comment on the other excellent references cited below, but I would also like to say many negative feedback mechanisms are shrinking quickly (such as the absorption of CO₂ by plankton, etc.), so that it is not only positive feedback mechanisms that we need to be realistic about.

Best,
Abrupt SLR

References:

[1]   Cai, W., Borlace, S., Lengaigne, M., Rensch, P.V., Collins, M., Vecchi, G., Timmermann, A., Santoso, A., McPhaden, M., Lixin Wu, Matthew H. England, Guojian Wang, Eric Guilyardi & Fei-Fei Jin, (2014), "Increasing frequency of extreme El Niño events due to greenhouse warming", Nature Climate Change, doi:10.1038/nclimate2100.
[2]   Cowtan, K. & Way, R.G., (2013), "Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends", Quarterly Journal of the Royal Meteorological Society, DOI: 10.1002/qj.2297.
[3]   England, M.H., McGregor, S., Spence, P., Meehl, G.A., Timmermann, A., Cai, W., Gupta, A.S., Michael J. McPhaden, M.J., Purich A. & Santoso, A., (2014), "Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus", Nature Climate Change, doi:10.1038/nclimate2106.
[4]   Fasullo, J.T. and Trenberth, K.E., (2012), "A Less Cloudy Future: The Role of Subtropical Subsidence in Climate Sensitivity", Science, vol. 338, pp. 792-794, 2012. http://dx.doi.org/10.1126/science.1227465.
[5]   Frederick, J.M., and Buffett, B.A., (2014), "Taliks in relict submarine permafrost and methane hydrate deposits: Pathways for gas escape under present and future conditions", Journal of Geophysical Research: Earth Surface, DOI: 10.1002/2013JF002987.
[6]   Hansen, J., Kharecha, P. and Sato, M., (2013), "Climate forcing growth rates: Doubling down on our Faustian bargain", Environ. Res. Lett., 8, 011006, doi:10.1088/1748-9326/8/1/011006.
[7]   Hansen, J., Sato, M., Russell, G. and Kharecha, P., (2013), "Climate sensitivity, sea level, and atmospheric carbon dioxide", Phil. Trans. R. Soc. A, 371, 20120294, doi:10.1098/rsta.2012.0294.
[8]   Hosking, J. Scott; Orr, Andrew; Marshall, Gareth J.; Turner, John; Phillips, Tony, (2013), "The influence of the Amundsen–Bellingshausen Seas low on the climate of West Antarctica and its representation in coupled climate model simulations", Journal of Climate, 26 (17). 6633-6648. 10.1175/JCLI-D-12-00813.1
[9]   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.
[10]   Ludescher, J., Gozolchiani, A., Bogachev, M.I.,  Bunde, A.,  Havlin, S., and Schellnhuber, H.J., (2014), "Very early warning of next El Niño", PNAS, 111 (6) 2064-2066, doi: 10.1073/pnas.1323058111.
[11]   Marks, A. A. and King, M. D.: "The effect of snow/sea ice type on the response of albedo and light penetration depth (e-folding depth) to increasing black carbon", The Cryosphere Discuss., 8, 1023-1056, doi:10.5194/tcd-8-1023-2014, 2014.
[12]   Meehl, G.A., Hu, A., Arblaster, J.M., Fasullo, J., Trenberth, K.E., (2013), "Externally Forced and Internally Generated Decadal Climate Variability Associated with the Interdecadal Pacific Oscillation", J. Climate, 26, 7298–7310. doi: http://dx.doi.org/10.1175/JCLI-D-12-00548.1
[13]   Mondav, R., Woodcroft, B.J., Kim, E.-H. McCalley, C.K., Hodgkins, S.B., Crill, P.M., Chanton, J., Hurst, G.B., VerBerkmoes, N.C., Saleska, S.R., Hugenholtz, P., Rich, V.I., & Tyson, G.W. (2014), "Discovery of a novel methanogen prevalent in thawing permafrost", Nature Communications, 5,3212doi:10.1038/ncomms4212.
[14]   National Research Council (NRC), (2013), Abrupt Impacts of Climate Change: Anticipating Surprises, Washington, D.C.: The National Academies Press.
[15]   Nisbet, E.G., Dlugokencky, E.J. and Philippe Bousquet, P.B., (2014), "Atmospheric Science: Methane on the Rise—Again", Science 31 January 2014: Vol. 343 no. 6170 pp. 493-495, DOI: 10.1126/science.1247828.
[16]   Rosenfeld, D., Sherwood, S., Woodand, R. and Donner, L., (2014), "Climate Effects of Aerosol-Cloud Interactions", Science 24 January 2014: Vol. 343 no. 6169 pp. 379-380. DOI: 10.1126/science.1247490.
[17]   Pistone, K., Eisenman, I. and Ramanathan, V., (2014), "Observational determination of albedo decrease caused by vanishing Arctic sea ice", PNAS, doi: 10.1073/pnas.1318201111.
[18]   Pithan, F. & Mauritsen, T., (2014), "Arctic amplification dominated by temperature feedbacks in contemporary climate models", Nature Geoscience, doi:10.1038/ngeo2071.
[19]   Power, S., Delage, F., Chung, C.,  Kociuba, G. and Keay, K., (2013), “Robust twenty-first-century projections of El Nino and related precipitation variability”, Nature, 502, 541-545, doi:10.1038/nature12580.
[20]   Previdi, M., Liepert, B.G., Peteet, D., Hansen, J., Beerling, D.J., Broccoli, A.J., Frolking, S., Galloway, J.N., Heimann, M., Le Quéré, C., Levitus, S. and Ramaswamy, V., (2013), "Climate sensitivity in the Anthropocene". Q. J. R. Meteorol. Soc., 139, 1121-1131, doi:10.1002/qj.2165.
[21]   Santer, B.D., Bonfils, C., Painter, J.F., Zelinka, M.D., Mears, C., Solomon, S., Schmidt, G.A., Fyfe, J.C., Cole, J.N.S., Nazarenko, L., Taylor, K.E. & Wentz, F.J., (2014), "Volcanic contribution to decadal changes in tropospheric temperature", Nature Geoscience, doi:10.1038/ngeo2098.
[22]   Schaller, N., Cermak, J., Wild, M., and Knutti, R., (2013), "The sensitivity of the modeled energy budget and hydrological cycle to CO2 and solar forcing", Earth Syst. Dynam., 4, 253-266, doi:10.5194/esd-4-253-2013.
[23]   Schuur, E.A.G. and Abbott, B., (2011), "High risk of permafrost thaw", Nature, 480, 32-33, Dec. 2011.
[24]   Sherwood, S.C., Bony, S., and Dufresne, J.D. (2014), "Spread in model climate sensitivity traced to atmospheric convective mixing", Nature; 505, pp 37–42; doi:10.1038/nature12829.
[25]   Vitale, D. and Bilancia, M., (2013) "Role of the natural and anthropogenic radiative forcings on global warming: evidence from cointegration–VECM analysis"; Environmental and Ecological Statistics; Volume 20, Issue 3, pp 413-444.
[26]   Wang, X., Piao, S., Ciais, P., Friedlingstein, P., Myneni, R.B., Cox, P., Heimann, M., Miller, J., Peng, S.P., Wang, T., Yang, H. and Chen, A., (2014), "A two-fold increase of carbon cycle sensitivity to tropical temperature variations", Nature, 2014; DOI: 10.1038/nature12915.
[27]   Wenju Cai, Simon Borlace, Matthieu Lengaigne, Peter van Rensch, Mat Collins, Gabriel Vecchi, Axel Timmermann, Agus Santoso, Michael J. McPhaden, Lixin Wu, Matthew H. England, Guojian Wang, Eric Guilyardi & Fei-Fei Jin, (2014), "Increasing frequency of extreme El Niño events due to greenhouse warming", Nature Climate Change, doi:10.1038/nclimate2100.
[28]   Xichen, L., Holland, D.M., Gerber, E.P., & Yoo, C., (2014), "Impacts of the north and tropical Atlantic Ocean on the Antarctic Peninsula and sea ice"; Nature; 505, 538–542; doi:10.1038/nature12945.
[29]   Zeebe, R., (2013), "Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions", PNAS, August 5, 2013, doi: 10.1073/pnas.1222843110.

[JimD]

Now when you consider the attached graph from AVOID showing pathways ways to achieve a 50% chance of limiting mean global temperature rise to 2 degrees C; to be honest one would need to point out to policy makers and the public that to achieve this goal would require a worldwide effort, from all governments simultaneously, comparable to the worldwide effort made during World War II (which as you point out is as likely as a snowball surviving in hell).

While I generally admire scientist greatly, and I am sure that the process-based science reports like AVOID are well intended, nevertheless, "The road to hell is paved with good intentions".  I believe that when government agencies say that a 2 degrees C limit is still achievable, many please think to themselves: "Good, the government has this situation under control, so I can go ahead and enjoy a fossil fuel rich life style, because the situation is under control."

I may be jaded, but I believe that the only way to get the policy makers, and the public, to take the strong measures needed to protect society, is the path that James Hansen is taking, which is not to sugar coat the truth, and to let people know that abrupt climate change (including abrupt sea level rise) is coming this century, because even if a miracle technology is invented it would take many decades to implement such a miracle on a worldwide basis; and by that time abrupt consequences will be upon us.

I realize that James Hansen has been communicating his message since the early 1980's and we are still on a pathway exceeding the RCP 8.5 scenario; but unless we can convince policy makers that what is coming is so un-naturally extreme (massive extinctions, massive food disruption, abrupt sea level rise) that it is indeed far worse than the terrorist threat (as John Kerry has pointed out); then I believe that efforts such as the AVOID effort will produce about as much impact as the Kyoto Protocol has had.

While speaking truth to power can be dangerous (as Hansen lost his job), I believe that it is necessary, and in my next post here I will try to present little bit of evidence about how serious our current situation really is.

Best,
ASLR

ASLR.  I would note that the common thought that it would take a global effort like in WWII is actually far off the mark.  If one reviews their history WWII was not in any way a real world war and there was not even close to a global effort underway.  This misconception comes from our US/European centric view of the world.  Total efforts were underway in the US, Russia, Japan and Europe.  The rest of the world was largely sitting on the sidelines watching.

What we need today is actually exactly what you state though.  A REAL global comprehensive effort.  Nothing else will do.  The problem is to act this way we have to evolve our thinking from the clan/tribal/nationality/country viewpoints common to human nature to a rational understanding that we are all in this together and that we will live or die together.  A tough nut to crack.  Not to mention that the horrifying (to some anyway) evil One World Government is pretty much what this kind of effort requires.  We know where that leads. 

While speaking truth to power can be dangerous (as Hansen lost his job), I believe that it is necessary, and in my next post here I will try to present little bit of evidence about how serious our current situation really is.

I am looking forward to seeing what you think.  But I must say that, while I respect Hansen tremendously, I don't think what he is doing amounts to anything significant.  The problems we have to solve to make real progress are at a much more difficult level than he is working at.  The problem is not figuring out the science, or explaining the science to policy makers and the public, or even figuring out comprehensive programs like the Wedges approach from years ago (which would have worked if implemented) or the AVOID program.  The problem is overcoming our evolutionary nature.  The change required is magnitudes beyond any conscious change humans have ever made in the past.  It is almost inconceivable that we could make such a change.  Even the most rational human beings (which probably make up less than 1/10 of a percent of us) demonstrate the blindness of subconscious decision making.  Green-BAU solutions like those promulgated by Hansen and others ignore that required change in human behavior which has to happen before you can get global cooperation.  Critical path problems first.  Human decision making and population levels.  If we can't consciously change human nature and we cannot implement drastic population reductions we have an unsolvable problem.

[AbruptSLR]

JimD,

Essentially, I concur with almost all of your points (including your critique of the current effectiveness of James Hansen's efforts); and if we had 2,000-years time, I would concur with your conclusions that we need to work on cleaning up human nature and the world population levels.  However, as I believe (due to both the climate sensitivity factors that I cited in my prior post and the West Antarctic Marine Ice Sheet sensitivity that I discuss in the "Antarctic" folder) that we have about 35-yrs before serious abrupt climate change consequences are upon society.  At this point multiple serious climate impact effects will cumulatively act like Pearl Harbor to get the public to provide support to leaders (global, national, local, or otherwise) that will offer protection from these abrupt climate consequences.  If we are lucky the majority of those leaders will be benevolent (while I imagine there will be a good share of despots) and will try to minimize the damages; but I believe that by 2050 a significant amount of SLR will be locked into the system for the next several hundred years, even if these benevolent leaders manage to stop all such "benevolent" leaders from falling into bad old habits; we will need to have a pretty effective feedback mechanism to these leaders that is better than the lobbyist feedbacks that we have in the current Democratic/Capitalist system.

[AbruptSLR]

I would like to add that I think that many people who come to the ASI blog intuitively understand that it is better to hope for a large, but hopefully manageable climate shock, well before 2050 such as: (a) the Arctic becoming effectively seasonally ice free by the summer of 2017; or (b) a series of closely spaced Super El Nino and or Super Typhoons/Hurricanes; that will be sufficient to shock leaders into action before we get too far down the rabbit hole.  The sooner we act the less expensive will be the final bill.

[Jim Hunt]

Injecting a little anecdotal local colour, a little bird told me there was a greater than 50% probability that James Hansen would be visiting Exeter in the not too distant future.

After the presentation on Thursday, we were invited to chat to a stranger for a while and then vote on whether to divide into small groups to discuss specific issues or discuss matters as one group. I voted for "focus groups", but I was in a minority!

The question of population was raised. It seems a recent Transition Exeter meeting discussed that very issue. Given the chance I might have mentioned something along the lines of this talk by Prof. Charles Godfray at the Houses of Parliament:



As it was one speaker from the floor suggested that once the "dangerous climate change" really kicks in the "population problem" would sort itself out pretty quickly! However somebody else suggested that currently "agriculture is very inefficient". They knew someone who was farming over 1000 feet up in Scotland. They had been assured all that was theoretically possible was raising a few sheep. In practice they also had pigs, cattle and chickens amongst other things.

On the topic of government ("benevolent" or otherwise!) there's a long article in this week's Economist entitled "What's gone wrong with democracy"

According to The Economist at least:

John Adams, America’s second president, once pronounced that “democracy never lasts long. It soon wastes, exhausts and murders itself. There never was a democracy yet that did not commit suicide.” He was clearly wrong.

Getting back to AVOID, the last I recall hearing of it was back at COP 15 in Copenhagen. Have I blinked and missed something?

[JimD]

Jim

I caught that Economist article and posted it in the Future Governmental Structures Topic.  A good read.

I note about the Adams quote the author is 'clearly incorrect' to claim Adams was wrong.  Such a claim as Adams' can only be proven right unless there was a time limit put on it.  And I note that the US, being the oldest living democracy, is not doing well at all.

[AbruptSLR]

Jim Hunt,

Regarding the man from the Met's comment that you should be more worried about the destruction of forests: It is not pointed out in either of the two following linked research that as current estimates of "climate sensitivity" do not include negative feedback provided by aerosols from at least pine forests (see articles); in order for Global Circulation Models, GCM's including this negative feedback to match historical records they will need to utilize higher effective "climate sensitivity" values; which should resulting in higher projections of global temperature increase, if plant growth/activity does not keep pace with the rate of future green house gas, GHC, emissions (say due to heat stress from a high radiative forcing pathway):

Mikael Ehn, Joel A. Thornton, Einhard Kleist, Mikko Sipilä, Heikki Junninen, Iida Pullinen, Monika Springer, Florian Rubach, Ralf Tillmann, Ben Lee, Felipe Lopez-Hilfiker, Stefanie Andres, Ismail-Hakki Acir, Matti Rissanen, Tuija Jokinen, Siegfried Schobesberger, Juha Kangasluoma, Jenni Kontkanen, Tuomo Nieminen, Theo Kurtén, Lasse B. Nielsen, Solvejg Jørgensen, Henrik G. Kjaergaard, Manjula Canagaratna, Miikka Dal Maso et al., (2014), " A large source of low-volatility secondary organic aerosol", Nature, 506, 476–479, doi:10.1038/nature13032

http://www.nature.com/nature/journal/v506/n7489/full/nature13032.html

Also, see:
http://www.bbc.com/news/science-environment-26340038


Abstract: "Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol, which is known to affect the Earth’s radiation balance by scattering solar radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aerosol, helping to explain the discrepancy between the observed atmospheric burden of secondary organic aerosol and that reported by many model studies. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere–aerosol–climate feedback mechanisms, and the air quality and climate effects of biogenic emissions generally."

Also, see the link to the following related reference:

Paasonen, P., et. al. (2013), "Evidence for negative climate feedback: warming increases aerosol number concentrations,", Nature Geoscience, 6, Pages: 438–442, doi: 10.1038/NGEO1800

http://www.nature.com/ngeo/journal/v6/n6/full/ngeo1800.html

[crandles]

  And I note that the US, being the oldest living democracy, is not doing well at all.

Seems plenty of debate about oldest democracy or should I say continuously running democracy:
http://www.theguardian.com/notesandqueries/query/0,,-80426,00.html

Greece,
Iceland,
Iroquois,
Isle of Man,
New Zealand,
Britain,
USA,
San Marino

are just some of the claims

[JimD]

  And I note that the US, being the oldest living democracy, is not doing well at all.

Seems plenty of debate about oldest democracy or should I say continuously running democracy:
http://www.theguardian.com/notesandqueries/query/0,,-80426,00.html

Greece,
Iceland,
Iroquois,
Isle of Man,
New Zealand,
Britain,
USA,
San Marino

are just some of the claims

Living sort of implies continuous unless we are talking about some zombie effect     I would say that the only one in your list which might have a logical argument is the Isle of Man.  The others are not credible as Britain was clearly not when the US declared independence, New Zealand did not exist, the Iroquois (I am part Iroquois btw) were long ago exterminated, Greece of course ceased to be a democracy before Christ was born and was a dictatorship in the 1970's, San Marino may not be one really yet - hard to say, and Iceland (which would easily be the longest otherwise) had a 46 year break in democracy which ended in 1845.   

So the US has a pretty fair claim in most respects.  Now if you want to argue that the US is a democracy in name only I will cede the field as that is my position as well.  And if you read the countries founding documents and the Constitution there was never any intent for it to be a full democracy in any case.   I just could not resist poking the Economist article a bit as it just had to have that optimistic bit in it.

[Jim Hunt]

ASLR - I didn't have time to get into an in depth discussion of academic papers with man from the Met.  I think his point was that more methane is likely to be produced by tropical wetlands in the near future than at high latitudes.

http://www.scientificamerican.com/article/global-methane-releases-could-be-wetlands-or-wellheads/

He may also have been thinking of some of the work of Prof. Peter Cox, such as "Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model"

We find that under a `business as usual' scenario, the terrestrial biosphere acts as an overall carbon sink until about 2050, but turns into a source thereafter. By 2100, the ocean uptake rate of 5 Gt C yr-1 is balanced by the terrestrial carbon source, and atmospheric CO2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models, resulting in a global-mean warming of 5.5 K, as compared to 4 K
without the carbon-cycle feedback.

not to mention:

During El Nino conditions the model simulates an increase in atmospheric CO2; this increase results from the terrestrial biosphere acting as a large source (especially in Amazonia), which is only partially offset by a reduced outgassing from the tropical Pacific Ocean.

During El Nino conditions the model simulates an increase in atmospheric CO2; this increase results from the terrestrial biosphere acting as a large source (especially in Amazonia), which is only partially offset by a reduced outgassing from the tropical Pacific Ocean.

The AVOID "glossy brochure" states that:

Climate models do not always correctly reproduce the mechanisms by which drought affects tropical forests. The impact of fire on forests is often still entirely overlooked in modelling simulations.

JimD - As crandles' link suggests, how exactly should one define "democracy"? I quite liked the view of Chad from Austin Texas:

Everyone could have saved a lot of typing by responding with these two words: "Gerald Ford". He wasn't elected. He was appointed. Democracy is not my beloved birth-nation's strong suit. Our strength lies in finding just how far we can push the boundaries of Democracy. Turns out it's pretty stretchy.

I'm not as optimistic as the man from The Economist either. I can't remember the last time I voted, unless you include that show of hands on Thursday.

[JimD]

JimD - As crandles' link suggests, how exactly should one define "democracy"? I quite liked the view of Chad from Austin Texas:

...

I'm not as optimistic as the man from The Economist either. I can't remember the last time I voted, unless you include that show of hands on Thursday.

Jim

I was just playing along with crandles for fun.  As I said in my response

Now if you want to argue that the US is a democracy in name only I will cede the field as that is my position as well.  And if you read the countries founding documents and the Constitution there was never any intent for it to be a full democracy in any case.   I just could not resist poking the Economist article a bit as it just had to have that optimistic bit in it.

I don't think we have any real democracy here in the US.  Only about 50% here vote.  The propaganda used to bombard the populace means that even the more affluent and older citizens who are the bulk of voters are very uniformed, the elected officials are wholely owned by the 1% and their minions, voting laws disenfranchise the minorities and poor, etc.  It is a mess.  A modern version of Rome.  As long as the Empire produces sufficient goods, circuses, and other entertainment we will just drift along with the tides of history.   

[AbruptSLR]

Jim Hunt,

Thanks for the great references on positive carbon-cycle feedbacks from the tropical rainforests (and wildfires), hopefully Earth System Models get their footing we will get a better handle on such complex coupled-system feedbacks.

Regarding JimD's comment that "... we will just drift along with the tides of history.": I post the attached image of the ever steepening curve of atmospheric CO2 concentration (with the following caption: "(An ever-steepening curve. CO2 levels from 1700 to the present. Image source: The Keeling Curve.)".  Thus unless the glossy AVOID brochure can strengthen the backbone of politicians worldwide, we may drift along the accelerating tide of an ever-steeping CO2 curve, rather than declaring the "Moral Equivalent of War" on fossil fuel emissions (it is not rocket science to understand that if greedy humans have found fossil resources in the ground, they will try to extract and sell that resource at even a small profit, thereby undercutting the economics of sustainable energies as we are currently seeing shale oil/gas doing in the US and soon worldwide).

[Jim Hunt]

I was just playing along with crandles for fun.

Understood. I feel sure we're on at least approximately the same wavelength. However I'm afraid I possess an extremely dry "English" sense of humour!

What I'm attempting to get at is to ask whether a type of "democracy" other than that currently practiced in the US or the UK is feasible, or not? By way of example, a couple of years ago I interviewed a member of Occupy Exeter about what he described as "an alternative model of democracy. A more direct and participatory form."

http://econnexus.org/andy-from-occupy-exeter-advocates-social-justice/

[AbruptSLR]

Jim Hunt/JimD,

To add my two cents (and dry California humor, ie because we are in a drought) about new forms of governance (or alternate forms of democracy), I would like to start with two quotes:

“If you know your enemies and know yourself, you will not be imperiled in a hundred battles... if you do not know your enemies nor yourself, you will be imperiled in every single battle.”  - Sun Tzu, 6th Century BC

and

"We have met the enemy and he is us." – Walt Kelly aka Pogo, 20th Century AD

In this regard: (a) we need individuals to improve themselves by stilling still long enough to know themselves; which will help them to understand other people, and how we can all co-operate to fight the common enemy of climate change (rather than just learn how we as individuals can stretch the boundaries of democracy to get more for ourselves as individuals); and (b) we need better feedback means for individuals to shine sunlight on governance, possibly through internet participation.

While generally my philosophizing doesn't do anyone much good, I will conclude with another quote:
"A day may come when the courage of men fails, when we forsake our friends and break all bonds of fellowship, but not this day.  An hour of woes and shattered shields, when the age of men comes crashing down, but it is not this day ... this day we fight." J.R.R. Tolkien aka Aragorn, Middle-Earth, before the gates of Mordor.

[JimD]

However I'm afraid I possess an extremely dry "English" sense of humour!

What I'm attempting to get at is to ask whether a type of "democracy" other than that currently practiced in the US or the UK is feasible, or not? By way of example, a couple of years ago I interviewed a member of Occupy Exeter about what he described as "an alternative model of democracy. A more direct and participatory form."

http://econnexus.org/andy-from-occupy-exeter-advocates-social-justice/

Anarchism!  I like it.  But it has no future that I can see a way to achieve.  Much too frightening for the general populace and completely unacceptable to the ruling (controlling) class.  We could propose a working alternative to social justice...feudalism, authoritarianism, fascism.  Oh wait!  Monarchy!   

ASLR, being more serious than us, has a point of course.  But the practical advise of Sun Tzu and the soaring prose of Tolkien can only resonate with a populace which understands the need and is willing to make the sacrifice required.  Aragorn had a better audience to work with than we do I am afraid.  I am not sure who the Dark Lord is but I am pretty sure that Saruman is a combination of Putin, Obama and Li Keqiang and that the 1% are the orcs.  We're in deep s**t!

[AbruptSLR]

JimD,

For what it is worth, Tolkien conceived of the Nazgul (Ringwraiths) when thinking of the soulless politicians and bureaucrats who started WWI without regard to the resulting loss of life, in the defense of disembodied power and the system that produced it.  Therefore, it seems reasonable to think of Sauron as the disembodied force that corrupts otherwise well intend men (who become Nazgul) who serve in defense of systems (capitalism, industrialism, fascism, etc.) that create power by separating wealth from its source (workers, artists, the earth, etc.), that is systems that are not sustainable.  That is why hobbits are the ultimate heroes, as they represent a sustainable why of life and living.

Thus by analogy to AVOID dangerous climate change we will need the little man (hobbits) to fight against soul-sucking systems created to accumulate power; possibly by ignoring their fears of losing their jobs, and taking responsibility for their governance (possibly by just voting true men into positions of responsibility).

Perhaps too seriously,
ASLR

[davidsanger]

...it is better to hope for a large, but hopefully manageable climate shock, well before 2050..

Certainly here in California, if there were a series of smaller earthquakes [not the big one which will eventually occur] then people and governments would be galvanized to take better precautions and prepare. I wish it were otherwise but we are a stubborn species and we often don't change our ways until the last minute.

[Jim Hunt]

Getting back to the science for the moment, I just came across this video which is part of Exeter University's current massive open online course on the topic of "Climate change: challenges and solutions".



For the first five minutes or so Professors Tim Lenton and Peter Cox discuss the  latter's new paper on "A two-fold increase of carbon cycle sensitivity to tropical temperature variations" and the Mauna Loa record.

We find that present terrestrial carbon cycle models do not capture the observed enhancement in CGR sensitivity in the past five decades. More realistic model predictions of future carbon cycle and climate feedbacks require a better understanding of the processes driving the response of tropical ecosystems to drought and warming.

[AbruptSLR]

Jim,

I found the video very interesting watching relatively clever scientists discussing the complex issue of climate sensitivity.  While it does convey to me that given enough time scientific specialists will slowly work their way towards a better understanding of a chaotic and non-stationary problem; however, I am concerned that we do not have many decades to slowly work this problem out for many of the reasons that I cited in my reply #7, including several very significant factors that the Exeter University people seemed to be ignoring including:
(a) Limitations on the future formation of clouds in the equatorial regions (due to down-drafting of the increasingly humid tropical atmosphere) probably means that the fast-response equilibrium climate sensitivity, ECS, will likely have a mean value closer to 4.5 instead of 3 degrees C.
(b) Most current values of ECS were calibrated to paleo-cases that were driven by solar radiative forcings rather than by GHG radiative forcing (as is the case for the Anthropocene), and climate sensitivity to GHG forcing is higher than to solar forcing.
(c) The Exeter people did not seem to fully appreciate how the negative PDO for the past 15-years has sequestered large amounts of heat in the Pacific Ocean, and that with the expected change soon to a positive PDO, than a good portion of that heat will be released from the Pacific Ocean.
(d) That the recently determined rate of decrease of Arctic albedo is twice as fast as previously assumed, which currently results in an increase in radiative forcing equal to 1/4 that of the CO2 emissions.
(e) That the current GCM models (used by the MET) do not fully account for the amount of methane being emitted by permafrost degradation.
(f) Also, while the video talked about the Wang et al (2014) finding that the carbon cycle sensitivity in the tropics is twice that assumed by the current GCM projections (including the MET); which is probably why the MET man that you talked to warned you about the need to consider the Sudd (because he left it out if his most current round of projections and he needs to work it into his future projections).

Best,
ASLR

[Oyvind Johnsen]

(b) Most current values of ECS were calibrated to paleo-cases that were driven by solar radiative forcings rather than by GHG radiative forcing (as is the case for the Anthropocene), and climate sensitivity to GHG forcing is higher than to solar forcing.

Why and how is climate sensitivity to GHG forcing higher than to solar forcing?

[wili]

At least an order of magnitude of difference in forcing. For more info, here's one place to start:

http://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm

[AbruptSLR]

Oyvind,

My statement about the relative difference of solar vs CO2 forcing is overly simplified, as what I was trying to convey was that CO2 also acidifies the ocean, which solar radiance does not.  At low levels of CO2 atmospheric concentration levels this effect of the acidification of the oceans may not be as significant as it will be at the higher CO2 atmospheric concentrations that we are approaching in the near future.  The significance of this difference between solar and CO2 forcing is illustrated by the following to reported cases:

The first Case is as follows:

James D. Wright and Morgan F. Schaller (2013), "Evidence for a rapid release of carbon at the Paleocene-Eocene thermal maximum", PNAS 2013 110 (40) 15908-15913

“Rapid” and “instantaneous” are words geologists don’t use very often. But Rutgers geologists use these exact terms to describe a climate shift that occurred 55 million years ago.
In a new paper in the Proceedings of the National Academy of Sciences, Morgan Schaller and James Wright contend that following a doubling in carbon dioxide levels, the surface of the ocean turned acidic over a period of weeks or months and global temperatures rose by 5 degrees centigrade – all in the space of about 13 years.
Scientists previously thought this process happened over 10,000 years.
Wright, a professor of earth and planetary sciences in the School of Arts and Sciences and Schaller, a research associate, say the finding is significant in considering modern-day climate change.
“We’ve shown unequivocally what happens when CO2 increases dramatically – as it is now, and as it did 55 million years ago,” Wright said. “The oceans become acidic and the world warms up dramatically. Our current carbon release has been going on for about 150 years, and because the rate is relatively slow, about half the CO2 has been absorbed by the oceans and forests, causing some popular confusion about the warming effects of CO2. But 55 million years ago, a much larger amount of carbon was all released nearly instantaneously, so the effects are much clearer.”
The window to this important decade in the very distant past opened when Wright helped a colleague, Kenneth Miller, and his graduate students split core samples they extracted from a part of southern New Jersey once covered by the ocean.
A close-up of the core at the heart of Wright's and Schaller's work. Note the regular dark bands – "like a tree ring," Schaller said.
The patterns found in the long cylinder of sediment told a story. There were distinct clay bands about 2 centimeters thick occurring rhythmically throughout the cores.
“They called me over and said, ‘Look at this,” said Schaller.  “What jumped out at me were these rhythmic clay layers, very cyclic. I thought, ‘Wow, these have got to mean something.”
Wright and Schaller surmised that only climate could account for the rhythmic pattern they saw. “When we see cycles in cores, we see a process,” Schaller said. “In this case, it’s like a tree ring. It’s giving us a yearly account through the sediments.“
This discovery provided the necessary data to finally solve the huge conundrum surrounding this event – the significant error in how fast the carbon was released.
Whatever the cause of the carbon release, -- some scientists theorize that a comet struck the earth -- Wright and Schaller’s contention that it happened so rapidly is radically different from conventional thinking, and bound to be a source of controversy, Schaller believes.
“Scientists have been using this event from 55 million years ago to build models about what’s going on now,” Schaller said. “But they’ve been assuming it took something like 10,000 years to release that carbon, which we’ve shown is not the case.  We now have a very precise record through the carbon release that can be used to fix those models.”

The second Case is as follows:


The following linked reference (followed by another link to a summary which, together with the two attached figures, is better than the abstract), that discusses the positive feedback caused by the acidification of the oceans reducing sulfur flux from the ocean which then results in more radiative forcing (see the second attached image) particularly over the Southern Ocean:

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1981.html

Global warming amplified by reduced sulphur fluxes as a result of ocean acidification; Katharina D. Six, Silvia Kloster, Tatiana Ilyina, Stephen D. Archer, Kai Zhang & Ernst Maier-Reimer; Nature Climate Change;  (2013); doi:10.1038/nclimate1981


http://www.mpimet.mpg.de/nc/en/communication/news/single-news/article/climate-change-ocean-acidification-amplifies-global-warming.html

Summary:

"Scientists at the Max Planck Institute for Meteorology (MPI-M), Dr. Katharina Six, Dr. Silvia Kloster, Dr. Tatiana Ilyina, the late Dr. Ernst Maier-Reimer and two co-authors from the US, demonstrate that ocean acidification may amplify global warming through the biogenic production of the marine sulfur component dimethylsulphide (DMS).

It is common knowledge that fossil fuel emissions of CO2 lead to global warming. The ocean, by taking up significant amounts of CO2, lessens the effect of this anthropogenic disturbance. The "price" for storing CO2 is an ongoing decrease of seawater pH (ocean acidification1), a process that is likely to have diverse and harmful impacts on marine biota, food webs, and ecosystems. Until now, however, climate change and ocean acidification have been widely considered as uncoupled consequences of the anthropogenic CO2 perturbation2. Recently, ocean biologists measured in experiments using seawater enclosures (mesocosms)3 that DMS concentrations were markedly lower in a low-pH environment (Figure 1).
When DMS is emitted to the atmosphere it oxidizes to gas phase sulfuric acid, which can form new aerosol particles that impact cloud albedo and, hence, cool the Earth's surface. As marine DMS emissions are the largest natural source for atmospheric sulfur, changes in their strength have the potential to notably alter the Earth's radiation budget. Based on the results from the mesocosm studies the researchers from the MPI-M have established relationships between pH changes and DMS concentrations in seawater. They projected changes in DMS emissions into the atmosphere in a future climate with enhanced ocean acidification using the MPI-M Earth system model4. In the journal Nature Climate Change it is demonstrated, that modeled DMS emissions decrease by about 18 (±3)% in 2100 compared to preindustrial times as a result of the combined effects of ocean acidification and climate change. The reduced DMS emissions induce a significant positive radiative forcing of which 83% (0.4 W/m2) can, in the model, be attributed to the impact of ocean acidification alone (Figure 2).
Compared to the Earth system response to a doubling of atmospheric CO2 this is tantamount to an equilibrium temperature increase between 0.23 and 0.48 K. Simply put, their research shows that ocean acidification has the potential to speed up global warming considerably.

References:
1. Gattuso, J-P. & Hansson, L. in Ocean Acidification (eds Gattuso, J-P. & Hansson, L.) 1_20 (Oxford Univ. Press, 2011).
2. Doney, S. C., Fabry, V. J., Feely, R. A. & Kleypas, J. A. Ocean acidification: The other CO2 problem. Annu. Rev. Mar. Sci. 1,
dx.doi.org/10.1146/annurev.marine.010908.163834, 169-192 (2009).
3. Archer, S. D. et al. Contrasting responses of DMS and DMSP 102 to ocean acidification in Arctic waters. Biogeosciences 10, 103,
dx.doi.org/10.5194/bg-10-1893-2013 (2013).
4. Jungclaus, J. H. et al. Climate and carbon-cycle variability over the last millennium. Clim. Past 6, dx.doi.org/10.5194/cp-6-723-2010, 723-737 (2010)."

[sidd]

That Wright paper astounds me every time i think about it. PETM carbon excursions occurred in an eyeblink, actually faster than we are releasing fossil carbon today. As such then, PETM represents a (most horrible) ceiling on anthropogenic greenhouse warming effects.

The other thing that sticks with me about the Wright paper is the remarkable support  for the argument provided by the measurement carbon isotope fractionation with depth.

sidd

[Shared Humanity]

That Wright paper astounds me every time i think about it. PETM carbon excursions occurred in an eyeblink, actually faster than we are releasing fossil carbon today. As such then, PETM represents a (most horrible) ceiling on anthropogenic greenhouse warming effects.

The other thing that sticks with me about the Wright paper is the remarkable support  for the argument provided by the measurement carbon isotope fractionation with depth.

sidd

It is interesting that the fossil records suggest that most mammal species survived and there is some evidence that speciation increased due to the climate changes. So, while 6C temperature increases are "incompatible with human civilization" there is evidence that the human species will survive.

A cause for optimism.

[werther]

A fast trajectory of CO2 rise under 'natural' conditions could, if proven right for the PETM, present a strong warning for us. I see ASLR has a study on it, which exactly notes that it was thought the rise to have taken many millenia during several phases.
That was what I'd been reading more often, IIRC. I'd like to see more evidence for this PETM release. I still have a strong mindset that our FF burning release since 1780 is resulting in  unprecedented warming pace in geological terms.
The same mindset forces me to imagine any release of carbon from submerged pleistocene seabeds and clathrates to resemble a long-term, slowly increasing stress relative to our short lives.
Not a sudden devastating 'burp'.
The unprecedented rapidness of what we're evoking may still be worrysome enough, as there's no 'time' for the ecological interdependences to adapt/reset/evolve.

[wili]

"there is evidence that the human species will survive."

But we might turn into Hobbits!

"[Hot conditions produced by] Increased CO2 levels may have promoted dwarfing"

http://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum

[AbruptSLR]

While the PETM may have been triggered by a comet impact (?), the following reference indicates that what many GCM projections have assumed would be slow-response positive feedback mechanisms, may respond more quickly to radiative forcing than previously thought:

The linked paper shows that climate sensitivity is likely higher than assumed in most prior GCM 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."
 

[Bruce Steele]

I have some reservations regarding the Wright paper. Ccg expressed similar reservations. If the entire
PETM carbon burp was instantaneous then there would have been a corresponding instantaneous .425 decrease in surface water pH. This in my opinion would have caused worldwide surface water undersaturation and consequent biological impacts for some shallow water fauna. The foraminifera extinctions associated with the PETM were bottom dwelling forams . It takes awhile for surface water pH perturbations to move into deep waters . The slow buildup of those conditions and the extinctions of deep water fauna seem to me to indicate a slower Co2 buildup rather than an instantaneous release. Just my opinion on things but I will reserve some skepticism until someone finds more corroborating evidence than some striated mud samples. 

[OldLeatherneck]

Has anyone got any data as to how much additional radiative forcing will be due to Water Vapor as the oceans continue to warm and expand?

Second question, is this included in any of the IPCC models??

[wili]

I'm no expert, but I assume that it is part of all the models. It is a very basic Charney (fast) feedback ant the physics are relatively straightforward, iirc. But I don't know the exact relative values right off the top of my head.

[AbruptSLR]

OldLeatherneck,

wili is right that the influence of water vapor is so key to global warming, that all GCM projections include this effect.  Skepticalscience.com provides a nice write-up on this fundamental topic at the following link (which is short and clear), which includes the following quote:

"Water vapour is the most dominant greenhouse gas. The greenhouse effect or radiative flux for water is around 75 W/m2 while carbon dioxide contributes 32 W/m2 (Kiehl 1997). These proportions are confirmed by measurements of infrared radiation returning to the Earth's surface (Evans 2006). Water vapour is also the dominant positive feedback in our climate system and a major reason why temperature is so sensitive to changes in CO2."

http://www.skepticalscience.com/print.php?r=44


The fundamental issue here is that the water vapor feedback loop actually makes global warming temperature changes caused by CO₂ (and other radiative forcings) even bigger; but the devil is in the details such as:

(a) water vapor can produce clouds (but does not necessarily need to), and while clouds can reflect long wavelength radiance from the Earth's surface, a positive feedback; clouds can also reflect incoming short wavelength solar radiance, a negative feedback.  This point emphasizes the importance of the finding so following reference; which shows that tropical atmospheric convective mixing of water vapor increases with global warming while suppressing cloud formation in the equatorial tropics where solar radiance is highest; which increases the positive feedback and suppresses the negative feedback.
Steven C. Sherwood, Sandrine Bony & Jean-Louis Dufresne; "Spread in model climate sensitivity traced to atmospheric convective mixing", Nature; 505, pp 37–42; (02 January 2014), doi:10.1038/nature12829

(b) Polar amplification is dominated by the fact that the polar atmosphere used to be relatively dry (it had low specific humidity), thus on a percentage basis a unit increase in atmospheric water vapor in the polar atmosphere produces much more global warming than in the tropics (which already has a lot of water vapor, ie it has a high specific humidity).  However, the water cycle in the Earth System is very complex and I cannot address it properly considering the many factors (precipitation, ENSO, cloud-cover, oceans, winds etc.)

(c) Finally, I post the attached image that shows a global-over ocean specific humidity anomaly graph from NOAA (2012); which shows the general upward trend of atmospheric specific humidity; however, this graph also makes it clear to me how important the PDO cycle is w.r.t. specific humidity as it is clear to me that specific humidity increased rapidly during the last positive phase of the PDO from 1982 to 1998, and then the rate of increase slowed down during the negative PDO phase from 1999 to 2014; therefore, I believe that the rate of increase of specific humidity will accelerate again as we enter a new positive PDO phase.

[AbruptSLR]

Bruce,

In regards to your reply #34, my purpose in citing Wright et al 2013 was not to discuss the specifics/merits of the various, and very convoluted, PETM triggering and development scenarios (in such convoluted cases I suspect that numerous mechanisms are involved).  Instead, what I was trying to get at was that not only does acidification of the oceans reduce dimethylsulphide emissions into the atmosphere, but also high acidification levels can have a marked effect on plankton which normally sequesters CO2, and that a reduction of the plankton-induced CO2 sequestration will also accelerate global warming.  Hopefully, future Earth Systems models will couple the acidification effects of CO2 into their projection (including those used by AVOID), because I do not believe that they current include this coupling.

Best,
ASLR

[AbruptSLR]

Other climate modeling considerations that I am concerned that AVOID underplays include what I call masking factors, which include such considerations as:

(a) Currently, the high aerosol (air pollution) concentrations, particularly in Asia and Africa, reflect a significant fraction of solar radiance.  However, China has signaled that I will make a major effect to reduce its air pollution sooner, rather than later, and thus the RCP forcing scenarios probably used by AVOID, assume too large of a negative feedback from these aerosols; which might mean that their forecasts are too rosy.
(b)  Obviously, the end of the immediate past negative phase of the PDO, means that we are now entering a nominally fifteen year period of relatively high radiative forcing (due to increase water vapor, Pacific venting of ocean heat content, and changes in the weather patterns).  As the AVOID projections almost certainly followed CMIP5 protocols, these projections could not have included the expected near-term surge in mean global warming from the coming positive PDO period.
(c) The non-linear rate of Arctic Sea Ice extent loss is almost certainly not captured by the AVOID models, implying again that they are underestimating future increases in mean global temperature rise.

Other masking considerations include AVOID's uncertainty as to what the correct current mean global temperature is, they almost certainly used pre-Conway et al (2013) values; and volcanic emission uncertainties.

[Jim Hunt]

This is not exactly cutting edge research on "missing feedbacks", but the UK's Royal Society in conjunction with the US's National Academy of Sciences have recently published a sort of "FAQ for policymakers" entitled:

Climate Change Evidence & Causes

They've even produced a YouTube video to go with it:



In it Professor Eric Wolff says that:

If we continue emitting carbon dioxide without any reductions then the effects will get really large by the end of the century. There could be increases in temperature as large as 3 to 5 degrees by the end of the century.

[TerryM]

Jim
Another quote from your link:
"As another example, Arctic warming could destabilise methane (a greenhouse gas) trapped in ocean sediments and permafrost, potentially leading to a rapid release of a large amount of methane. If such a rapid release occurred, then major, fast climate changes would ensue."
[/size][/color]
[/size]This was from question 19[/color]
[/size][/color]
[/size]Terry[/color]

[Jim Hunt]

Hot off the presses - "International study combines aircraft and ground data to measure the “breath” of the Amazon forest":

An international team of scientists found that the amount of yearly rainfall was the driving factor behind the amount of carbon dioxide (CO2) taken up and released from Amazonia in 2010 and 2011. During a wet year, the Amazon forests were roughly carbon-neutral: Forests “inhaled” more carbon dioxide than they “exhaled,” but biomass burning, which releases carbon dioxide, compensated for the difference. In contrast, during a very dry year forest growth stalled and biomass burning increased, resulting in the region “exhaling” substantial amounts of carbon dioxide to the atmosphere.

More at: http://cires.colorado.edu/news/press/2014/amazoniandrought.html

[wili]

During a wet year, the Amazon forests were roughly carbon-neutral: Forests “inhaled” more carbon dioxide than they “exhaled,” but biomass burning, which releases carbon dioxide, compensated for the difference. In contrast, during a very dry year forest growth stalled and biomass burning increased, resulting in the region “exhaling” substantial amounts of carbon dioxide to the atmosphere.

So then the Amazon is already a net carbon emitter? That's a big positive (exacerbating) feedback to tip!

[wili]

Leaked IPCC Report Reveals Unsettling Findings

#Time2Act

http://climatestate.com/2014/03/11/leaked-ipcc-report-reveals-unsettling-findings-time2act/.

[Shared Humanity]

wili......Have you been able to locate the leaked IPCC report? Could you provide link? If not, how do we conduct a rigorous search in order to blast it all over the internet?

I would love to read it before they modify the heck out of it for the final watered down report.

[wili]

I think they are referring to the stuff that came out last year: http://bigstory.ap.org/article/warming-report-sees-violent-sicker-poorer-future

[icefest]

They could be referring to the parts due to be published this year: http://en.wikipedia.org/wiki/IPCC_Fifth_Assessment_Report

[Jim Hunt]

The Royal Society have now published another sort of FAQ about their recent "Climate Change Evidence & Causes" document. The RS answers questions posed online. One Monckton of Brenchley,seems to have asked quite a lot!

The whole thing can be viewed online, or the top twenty questions and answers are available for download.

The Rabett is also discussing the contents as we speak.

[wili]

If the world continues to burn fossil fuels at the current rate, global warming will rise 2 degrees Celsius by 2036, crossing a threshold that many scientists think will hurt all aspects of human civilization: food, water, health, energy, economy and national security.

--M. Mann

http://www.scientificamerican.com/article/mann-why-global-warming-will-cross-a-dangerous-threshold-in-2036/