Mauna Loa CO2

[crandles]

While CO2 growth is faster than linear, I suspect it is slower than exponential (I have not checked this recently) and therefore temperature rise should be less than linear.

Thought I better check, and I think I got it completely wrong:

CO2more thanExponential by crandles2011, on Flickr

seems it is repeatedly outpacing exponential growth.

[crandles]

crandles,
Your statement that linear growth in global surface temperatures needs exponential growth in CO2 ignores the positive feedback mechanisms associated with global warming.  As indicated by the attached image (with the following caption) from Meinshausen et.al. (2011), even linear growth of atmospheric CO2 concentrations for RCP 8.5 result in linear increases in mean global surface temperatures, beyond 2100:

Figure caption: "For RCP 8.5 and RCP 3-PD/2.6, Actual and Projected Values for: (a) Atmospheric CO2 Concentrations; (b) Radiative Forcing, and (c) Global-mean Surface Temperature Differences from Pre-Industrial Levels, from Meinshausen et.al. 2011"

Best, ASLR

That looks to be roughly linear CO2 growth from about 2050. After 2050 the temperatures increase much less than linearly. Between 2000 and 2050, the co2 growth is much more than linear and the temperature growth is slightly above linear. So I don't think the graphs provided show I am wrong on this aspect.

http://www.skepticalscience.com/exponential-increase-CO2-warming.htm

What the science says...
Despite the logarithmic relationship between CO2 and surface temperatures, atmospheric CO2 levels are rising so fast that unless we dramatically decrease our emissions, global warming will accelerate over the 21st Century.
Climate Myth...
An exponential increase in CO2 will result in a linear increase in temperature

There is a logarithmic relationship between radiative forcing (which is directly proportional to the change in surface temperature at equilibrium) and the atmospheric CO2 increase.  Note that we are not currently at equilibrium as there is a planetary energy imbalance, and thus further warming 'in the pipeline' from the carbon we've already emitted.  Therefore, estimates of the rate of warming due to CO2 thus far will will be underestimates, unless accounting for this 'warming in the pipeline'.
This logarithmic relationship means that each doubling of atmospheric CO2 will cause the same amount of warming at the Earth's surface.  Thus if it takes as long to increase atmospheric CO2 from 560 to 1120 parts per million by volume (ppmv) as it did to rise from 280 to 560 ppmv, for example, then the associated warming at the Earth's surface will be roughly linear.

I may still be mis-interpreting this but that seems to be saying there is a logarithmic relation so exponential growth in CO2 over a long time period causes linear growth in temperature. However over shorter time periods the current imbalance may be more important. As growth in CO2 has been faster than exponential for last several decades, the current imbalance is likely to be higher so that exponential growth in CO2 from now would result in faster than linear growth in temperature in the next few decades.

Please correct me if I am wrong (yet again).

[AbruptSLR]

crandles,

My point about considering other positive feedback mechanism was meant to imply that the increase in mean global temperatures is not only a function of CO2 concentrations in the atmosphere.  RCP 8.5 assumes somewhat high methane emissions, but does not adequately consider methane emission from expected permafrost degradation.  Similarly, RCP 8.5 underestimates the current amounts of Black Carbon emission and its future scenarios do not adequately account for Black Carbon from wild fires.  Furthermore, current CMIP5 projections of mean global temperature increases assume a nominal Equilibrium Climate Sensitivity, ECS, of about 3.0 degrees C; while there is growing evidence that 3.0 degrees C is the lower bound for ECS, and it may well be higher; which would further raise future temperature increases for any increasing trend for anthropogenic CO2 emissions.

Best,
ASLR

[viddaloo]

IPCC = silliness.

[Pmt111500]

Water vapor is the strongest ghg, and adding to the curvature of the graphoid (2*CO2 alone = 1degree, with feedbacks, 3 or more), but unless there are non-condensible gases in atmosphere it's pretty useless at this distance from the sun. The same image for Mauna Loa Weekly data since 1974 (the remarkably few gaps in data infilled with straight lines).

[crandles]

Water vapor is the strongest ghg, and adding to the curvature of the graphoid (2*CO2 alone = 1degree, with feedbacks, 3 or more), but unless there are non-condensible gases in atmosphere it's pretty useless at this distance from the sun. The same image for Mauna Loa Weekly data since 1974 (the remarkably few gaps in data infilled with straight lines).

Sorry but I haven't a clue what you are trying to say with
"but unless there are non-condensible gases in atmosphere it's pretty useless at this distance from the sun"

If there was only water vapour and other condensible gases in atmosphere



wouldn't that make it hotter than if there was only CO2 and no water vapour?

(I agree that water vapour is strongest GHG but it is a feedback not a forcing. Low 11 day residence means water vapour level rapidly adjusts to temperature. Therefore CO2 is strongest GHG forcing that we have to worry about.)

[AbruptSLR]

crandles,

Your point that carbon dioxide is the dominant radiative forcing, and that water vapor and clouds are dominant feedback mechanisms, is all very true as indicated by the 2010 information (both extract and simple image) from the following NASA link.  Nevertheless, I still cannot help but to believe that this traditional IPCC view of climate change gives both the public and decision makers the impression that they have several decades of time in order to set-straight GHG emissions before sustaining unacceptable consequences (ie consequences that will cause society to take appropriate action).  My major concern is that as mean global temperature increases many positive feedback factors increase non-linearly and dominate negative feedback factors.  As this thread is focused on carbon dioxide, I will not go on about climate sensitivity, but I hope that readers remember atmospheric carbon concentrations are just a part of the story.

http://www.nasa.gov/topics/earth/features/co2-temperature.html

Extract: "A companion study led by GISS co-author Gavin Schmidt that has been accepted for publication in the Journal of Geophysical Research shows that carbon dioxide accounts for about 20 percent of the greenhouse effect, water vapor and clouds together account for 75 percent, and minor gases and aerosols make up the remaining five percent. However, it is the 25 percent non-condensing greenhouse gas component, which includes carbon dioxide, that is the key factor in sustaining Earth’s greenhouse effect. By this accounting, carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth’s greenhouse effect."

Best,
ASLR

[AbruptSLR]

For those who want to see the annual relative forcing contribution of CO2 compared to non-CO2 GHGs (not including Black Carbon) from 1700 to 2013, I provide the attached plot from the following link:

http://www.esrl.noaa.gov/gmd/aggi/aggi.html

[Pmt111500]

Sept 28 - Oct 4, 2014,  395.33 ppm (+2,07ppm from last year)

Checking the weekly values over the years, the rise in CO2 is spread out all over the year. This isn't all too surprising since Mauna Loa is pretty far from major polluters and any spikes in CO2 (save the El Nino induced ones) have been diluted over most of the globe by the time they get to Hawaii. The constant activity of plants in moist tropics further ensures smoother curves here than elsewhere. I though there would be a noticeable spike in the speed of the rise during winters (due NH) but it isn't there. Maybe it could be found on more northern stations.

[Pmt111500]

October 5-11, 2014:     395.48 ppm  (+2,19 ppm from the
Weekly value from 1 year ago:     393.29 ppm)

[icefest]

Sept 28 - Oct 4, 2014,  395.33 ppm (+2,07ppm from last year)

Checking the weekly values over the years, the rise in CO2 is spread out all over the year. This isn't all too surprising since Mauna Loa is pretty far from major polluters and any spikes in CO2 (save the El Nino induced ones) have been diluted over most of the globe by the time they get to Hawaii. The constant activity of plants in moist tropics further ensures smoother curves here than elsewhere. I though there would be a noticeable spike in the speed of the rise during winters (due NH) but it isn't there. Maybe it could be found on more northern stations.

I think the much greater magnitude of change due to the NH growing season will drown out most analysis.
Secondly, even if anthropogenic carbon release is larger in the NH winter, then comparing it to the previous year will not reflect this, as the spike would have existed last winter too.

Id you have a look at south pole CO2 levels they display an incredibly steady rise.

[Pmt111500]

October 12 - 18, 2014: 395.56 ppm (+1,96ppm from the
Weekly value from 1 year ago, 393.60 ppm)

[crandles]

Week beginning on October 19, 2014:     395.82 ppm
Weekly value from 1 year ago:     393.90 ppm

October 28 - 398.68  maybe it will get revised, but then the following graph shows several readings around 399.

October 2013 averaged 393.66




probably just a brief spike I expect. I hope.

[pikaia]

We have seen spikes like that in the past, but they were soon revised downwards.

[werther]

Pikaia it may be like that for you, but count me out of ‘we’, please.
I don’t think there will be a marked change in the trend, but measurements like this seem to me to relate to the six week long flatline in feb-march this spring. It could mark a strong volatility driven by the unusual SST-patterns in the North Pacific as well as influences induced by the passage of cyclones like Ana near Hawaii.
Rather than being indifferent, I tend to take any feature serious under the given dire circumstances.

[Apocalypse4Real]

There are alot of things missed in the messiness of the current global CO2 mean based upon just glancing at the MLO numbers. While MLO is useful, it misses the high Arctic concentrations, especially those at lower altitudes than 666 mb.

The first image is METOP IASI 2-A CO2 for Oct 30 2014 for 12-24 hrs at 672 mb. It approximates the ESRL mb reading environment.

The second image is the same time period, just at a much lower altitude to portray the higher readings.

[Pmt111500]

Oct. 26 - Nov. 1, 2014: 397.22 ppm (+3.05ppm from the value of
Oct. 26 - Nov. 1, 2013: 394.17 ppm )

remembering how warm the oct-nov was last year, this is nothing special. could be that this measure hits even +3.5ppm sometime in dec.

[Pmt111500]

  November 2 - 8, 2014: 396.68 ppm
 (+2.26 ppm from the value of  last year)
November 2 - 8, 2013: 394.42 ppm

Looks like natural systems have catched up the normal rate of increase. Too bad this info comes from USA, the majority of the government of which is known to be against science.

[Pmt111500]

November 9-15, 2014 to be 396.90 ppm , this is  a rise of 1.52 ppm from the value of the last year, same time of the year, November 9-15, 2013, that was 395.38 ppm. [sarc] Choosing republicans to stall the government and reduce the funding of Mauna Loa observatory has clearly made a mark in the speed of the rise [/sarc]

[crandles]

Could always compare to the following week:

2013  11  10  2013.8589    395.38  7         
2013  11  17  2013.8781    394.85  7 

394.85 to 396.9 is a rise of 2.05 in less than a year

Weekly averages don't seem to mean much. Daily numbers even less there was a number less than 391 which has been revised away. Even monthly rise numbers jump about quite a bit.

Global average monthly should be better but even there Sept 2014 2.09 annual rise is up from 1.61 for July but down from 3.51 for July 2013.

Think we need an Enso adjusted timeseries to make any sense of it.

[pikaia]

At the start of the year there was a strange plateau in the curve, so it will be interesting to see how it compares with the data for early next year - there could be substantial differences.

Does anyone now the cause of the plateau?

[Steven]

NASA Computer Model Provides a New Portrait of Carbon Dioxide:

http://www.nasa.gov/press/goddard/2014/november/nasa-computer-model-provides-a-new-portrait-of-carbon-dioxide/

<a href="https://www.youtube.com/v/x1SgmFa0r04" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">https://www.youtube.com/v/x1SgmFa0r04</a>

[Pmt111500]

Nov. 16 - 22, 2014 - 397.26 ppm (+2.55 ppm from the value last year
Nov. 16 - 22, 2013 - 394.71 ppm

It appears that the reporting laboratory was again forcibly taken over by the democrats, who can be trusted to keep the economy going BAU, as indicated by the reported rise of CO2.  The electronically voting wing of Republicans, called Teabaggers, are probably currently now shooting at unarmed civilians at Ferguson, as opposed to faking statistics and lying of science, so the next weeks report might also be reasonably accurate showing continued BAU.

[werther]

As ever interesting to keep an eye on The Keeling Curve.
While the PDO is getting into record territory, readings highest since mid 1997 and late 2002, CO2 measured on Mauna Loa is now very close to the 400 ppm benchmark again.
Are the two data-lines related? I guess the readings at Mauna Loa do exhibit a regional signal, while it's situation generally well reflects the worldwide trend.
We know warm water has a lower CO2 uptake.
I checked Barrow last night, as well as Summit, GR. Trends perform over there without the 'uptick' in recent Mauna Loa data.

[Steven]

Early Results from NASA’s Orbiting Carbon Observatory-2 Mission (OCO-2) :

http://www.nasa.gov/jpl/oco2/nasas-spaceborne-carbon-counter-maps-new-details




Moreover, there was a press conference about these results, today, at the AGU fall meeting.  The 48-minute long video of the press conference is here, pdf of the slides is here.

[AbruptSLR]

Early Results from NASA’s Orbiting Carbon Observatory-2 Mission (OCO-2) :

I have to admit that I was a little bit surprised to see the amount of CO2 concentrated above the Amazon, Congo and Indonesia rainforests being higher than almost any Northern Hemisphere area from Oct 1 to Nov 11 2014.

[crandles]

I have to admit that I was a little bit surprised to see the amount of CO2 concentrated above the Amazon, Congo and Indonesia rainforests being higher than almost any Northern Hemisphere area from Oct 1 to Nov 11 2014.

Dec to Feb would be very different. Oct 1 - Nov 11 sounds quite close to Dec to Feb peak times for Northern hemisphere so I would agree it does seem a bit surprising.



Around 395 for Barrow Oct 1 - Nov 11 is perhaps below average while southern hemisphere remains at about average. Perhaps seems plausible when you get to that level, assuming the resolution isn't enough to pick out power plants.

[TeaPotty]

I have to admit that I was a little bit surprised to see the amount of CO2 concentrated above the Amazon, Congo and Indonesia rainforests being higher than almost any Northern Hemisphere area from Oct 1 to Nov 11 2014.

This article might have an answer...

NASA CO2 map reveals impact of forest clearance
http://www.rtcc.org/2014/12/19/nasa-co2-map-reveals-impact-of-forest-clearance/

But the biggest swathes of red – signifying a high concentration of the greenhouse gas – appeared over the southern hemisphere.

“Preliminary analysis shows these signals are largely driven by the seasonal burning of savannas and forests,” explained NASA scientist Annmarie Eldering.

Farmers in Brazil and southern Africa are known to clear land in springtime. The images suggest this might have a bigger impact on the atmosphere than previously thought.

[Sleepy]

I have to admit that I was a little bit surprised to see the amount of CO2 concentrated above the Amazon, Congo and Indonesia rainforests being higher than almost any Northern Hemisphere area from Oct 1 to Nov 11 2014.

The video might have the answer at 08:00, they don't get a lot of data at the highest latitudes.

[AbruptSLR]

I have to admit that I was a little bit surprised to see the amount of CO2 concentrated above the Amazon, Congo and Indonesia rainforests being higher than almost any Northern Hemisphere area from Oct 1 to Nov 11 2014.

This article might have an answer...

NASA CO2 map reveals impact of forest clearance
http://www.rtcc.org/2014/12/19/nasa-co2-map-reveals-impact-of-forest-clearance/

But the biggest swathes of red – signifying a high concentration of the greenhouse gas – appeared over the southern hemisphere.

“Preliminary analysis shows these signals are largely driven by the seasonal burning of savannas and forests,” explained NASA scientist Annmarie Eldering.

Farmers in Brazil and southern Africa are known to clear land in springtime. The images suggest this might have a bigger impact on the atmosphere than previously thought.

All,

Thanks for pointing out that the scientist think that seasonal burning of the savannas and rainforests may be part of the explanation, if so then with population growth this trend should accelerate quickly.

ASLR

[silkman]

January 1st brings the first daily reading over 400ppm, more than two months earlier than last year:

https://scripps.ucsd.edu/programs/keelingcurve/

Upwards and onwards it seems!

[AbruptSLR]

The linked reference indicates that the seasonal atmospheric CO₂ amplitude will continue to increase in the 21st century as increased vegetation growth in the Spring and Summer is counter balanced by increased CO₂ emissions when this vegetation decays in the Fall and Winter (like now):

Zhao, F. and Zeng, N., (2014), "Continued increase in atmospheric CO2 seasonal amplitude in the 21st century projected by the CMIP5 Earth system models", Earth Syst. Dynam., 5, 423-439, doi:10.5194/esd-5-423-2014

http://www.earth-syst-dynam.net/5/423/2014/esd-5-423-2014.html

Abstract. In the Northern Hemisphere, atmospheric CO2 concentration declines in spring and summer, and rises in fall and winter. Ground-based and aircraft-based observation records indicate that the amplitude of this seasonal cycle has increased in the past. Will this trend continue in the future? In this paper, we analyzed simulations for historical (1850–2005) and future (RCP8.5, 2006–2100) periods produced by 10 Earth system models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Our results present a model consensus that the increase of CO2 seasonal amplitude continues throughout the 21st century. Multi-model ensemble relative amplitude of detrended global mean CO2 seasonal cycle increases by 62 ± 19% in 2081–2090, compared to 1961–1970. This amplitude increase corresponds to a 68 ± 25% increase in net biosphere production (NBP). The results show that the increase of NBP amplitude mainly comes from enhanced ecosystem uptake during Northern Hemisphere growing season under future CO2 and temperature conditions. Separate analyses on net primary production (NPP) and respiration reveal that enhanced ecosystem carbon uptake contributes about 75% of the amplitude increase. Stimulated by higher CO2 concentration and high-latitude warming, enhanced NPP likely outcompetes increased respiration at higher temperature, resulting in a higher net uptake during the northern growing season. The zonal distribution and spatial pattern of NBP change suggest that regions north of 45° N dominate the amplitude increase. Models that simulate a stronger carbon uptake also tend to show a larger increase of NBP seasonal amplitude, and the cross-model correlation is significant (R=0.73, p< 0.05).

[maltose]

How does CO2 increase per year  correlate with yearly temperature? I assume positively. 1998 seems to have the record at 2.93 ppm and 2002, 2005, 2010,and 2012 are pretty high. What does that mean for 2014, the (supposed) new global record?

[AbruptSLR]

How does CO2 increase per year  correlate with yearly temperature? I assume positively. 1998 seems to have the record at 2.93 ppm and 2002, 2005, 2010,and 2012 are pretty high. What does that mean for 2014, the (supposed) new global record?

Maltose,

The linked article answers your question:

Philip Goodwin, Richard G. Williams & Andy Ridgwell, (2015), "Sensitivity of climate to cumulative carbon emissions due to compensation of ocean heat and carbon uptake", Nature Geoscience, Volume: 8, Pages: 29–34, doi:10.1038/ngeo2304

http://www.nature.com/ngeo/journal/v8/n1/full/ngeo2304.html

Abstract: "Climate model experiments reveal that transient global warming is nearly proportional to cumulative carbon emissions on multi-decadal to centennial timescales. However, it is not quantitatively understood how this near-linear dependence between warming and cumulative carbon emissions arises in transient climate simulations6, 7. Here, we present a theoretically derived equation of the dependence of global warming on cumulative carbon emissions over time. For an atmosphere–ocean system, our analysis identifies a surface warming response to cumulative carbon emissions of 1.5 ± 0.7 K for every 1,000 Pg of carbon emitted. This surface warming response is reduced by typically 10–20% by the end of the century and beyond. The climate response remains nearly constant on multi-decadal to centennial timescales as a result of partially opposing effects of oceanic uptake of heat and carbon. The resulting warming then becomes proportional to cumulative carbon emissions after many centuries, as noted earlier. When we incorporate estimates of terrestrial carbon uptake, the surface warming response is reduced to 1.1 ± 0.5 K for every 1,000 Pg of carbon emitted, but this modification is unlikely to significantly affect how the climate response changes over time. We suggest that our theoretical framework may be used to diagnose the global warming response in climate models and mechanistically understand the differences between their projections."

[maltose]

Thanks, AbruptSLR, this is very interesting. I guess I was unclear; I was initially asking the question the opposite direction (how a hot year affects CO2 emissions)? I know that the trendline is up for emissions but it varies widely from year to year. I just wondered if increased human emissions in 2014 and (probably) the hottest year on record would make an increase in CO2 over > 3 ppm/year in 2014.

[AbruptSLR]

Thanks, AbruptSLR, this is very interesting. I guess I was unclear; I was initially asking the question the opposite direction (how a hot year affects CO2 emissions)? I know that the trendline is up for emissions but it varies widely from year to year. I just wondered if increased human emissions in 2014 and (probably) the hottest year on record would make an increase in CO2 over > 3 ppm/year in 2014.

maltose,

I think that focusing on annual fluctuations is more appropriate for meteorology than for climate change trends.  From a long-term climate change trend-line point of view, it is the carbon emissions that drive global warming; while in any given year natural carbon emissions (or changes in absorption) can fluctuate for a large number of reasons.  You can monitor the Mauna Loa readings yourself at the following link to determine the 2014 record, or any other timeframe that you like at the following link:

http://keelingcurve.ucsd.edu/

Best,
ASLR

[Laurent]

For the moment we are at 2.07 ppm/year in average...seems to be exponential...gloups...
http://co2now.org/Current-CO2/CO2-Trend/acceleration-of-atmospheric-co2.html

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 (4 years only)

[crandles]

December 2014 averages 398.78  (2013 396.81 so increase 1.97 on the year)

For Jan 2015 to be 400 or over requires an increase of 1.22.

The odds for this seem to vary quite a bit depending how many years data you use:

last year didn't rise enough
3 of last 4 years did rise enough
6 of last 10 years did rise enough
only 12 of last 30 years did rise enough

http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo.png

doesn't hint at a change in seasonal pattern and January is about on the trend line so the known increase in amplitude won't have much if any effect.

So presumably the increasing odds is a feature of the growth rate increasing (more than exponentially).

One year doesn't make or change a trend so do we assume the chance is at least 75%?

Probably ENSO adjustment is necessary to get a sensible odds prediction.

[AbruptSLR]

December 2014 averages 398.78  (2013 396.81 so increase 1.97 on the year)

For Jan 2015 to be 400 or over requires an increase of 1.22.

The odds for this seem to vary quite a bit depending how many years data you use:

last year didn't rise enough
3 of last 4 years did rise enough
6 of last 10 years did rise enough
only 12 of last 30 years did rise enough

http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo.png

doesn't hint at a change in seasonal pattern and January is about on the trend line so the known increase in amplitude won't have much if any effect.

So presumably the increasing odds is a feature of the growth rate increasing (more than exponentially).

One year doesn't make or change a trend so do we assume the chance is at least 75%?

Probably ENSO adjustment is necessary to get a sensible odds prediction.

Regarding corrections for probable El Nino events, we all need to remember that during El Nino events the atmospheric CO2 concentration increases due to both degradation of tropical rainforests and CO2 venting of the coast of Peru during El Nino events (see the 2014 El Nino thread).  Furthermore, an El Nino event is forecast by NOAA beginning in the summer of 2015

[JimD]

But Crandles are you not falling into the trap that ASLR mentioned above in that your post is talking about a Dec monthly fluctuation rather than what is happening over a more meaningful period?

Rather than what has happened in individual months over that time span what has happened to the yearly average over it?

The average yearly rise over your sample of years is:

2014 -            2.32  yields an expected Jan 2015 of 401.1
last 4 years -  2.22                     "                             401.0
last 10 years - 2.28                    "                             401.0
last 30 years - 1.81                    "                             400.6

This results in numbers which indicate it is very likely to pass 400, but not certain of course.

http://www.esrl.noaa.gov/gmd/ccgg/trends/#mlo_growth

Or am I misunderstanding your post?

[wili]

"during El Nino events the atmospheric CO2 concentration increases due to both degradation of tropical rainforests and CO2 venting of the coast of Peru during El Nino events (see the 2014 El Nino thread).  Furthermore, an El Nino event is forecast by NOAA beginning in the summer of 2015"

I thought that it was also because the warmer oceans, even where they don't actually vent CO2, just don't absorb as much as they would in other years, so more stays in the atmosphere.

[crandles]

There may well be problems with my method for predicting Jan 2015. However, your method seems to ignore the latest data and tries to predict a whole year ahead rather than just a month.

I would be inclined to also look at whether Dec vs Nov rise was particularly large or small to improve my method rather than ignore the latest data.

Dec rise of 1.65 is above average so maybe that will tend to make the Dec to Jan smaller than typical.

I don't think it is as certain as your figures seem to suggest.


It may well not be a good idea to focus on too much detail at too short a timeframe. But if you do, I would have thought estimating a month ahead is likely to be more accurate than estimating a year ahead.

.

MEI
2013   .038   -.165   -.171   .01   .108   -.242   -.436   -.586   -.175   .102   -.08   -.3
2014   -.318   -.269   -.017   .152   .932   .878   .816   .858   .5   .36   .712   .578
http://www.esrl.noaa.gov/psd/enso/mei/table.html

Peak seems to be AprMay - JulAug, AugSep & SepOct figures are rather low and OctNov &NovDec figures just a little lower than Peak values.

It could be that the peak values are still feeding through into larger than average rises so another month of above average rise should be expected. Or maybe we have passed the peak effect and now we should get slightly below average rises? If "warmer oceans, even where they don't actually vent CO2, just don't absorb as much as they would in other years" is an important factor then I would expect quite a delay and another large rise in Jan so it is highly likely for Co2 to be over 400 in Jan 2015.

[wili]

Surely, then, the average for this year will be well over 400, no?

[crandles]

Surely, then, the average for this year will be well over 400, no?

With 2014 average at 398.55, yes. Last time it failed to rise 1.45 was 1999 to 2000. 1999 and 2000 were both la Nina years falling entirely within JJA 1998 – FMA 2001. Perhaps not completely certain, but pretty close.

[AbruptSLR]

"during El Nino events the atmospheric CO2 concentration increases due to both degradation of tropical rainforests and CO2 venting of the coast of Peru during El Nino events (see the 2014 El Nino thread).  Furthermore, an El Nino event is forecast by NOAA beginning in the summer of 2015"

I thought that it was also because the warmer oceans, even where they don't actually vent CO2, just don't absorb as much as they would in other years, so more stays in the atmosphere.

wili,

There are many different feedback mechanisms and I was only citing the strongest ones for emitting carbon dioxide.

Best,
ASLR

[Yuha]

When will the seasonally corrected monthly mean at Mauna Loa reach 400?



For Dec 2014 the value was 399.60.
ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_mm_mlo.txt

It could happen already this month if the monthly mean is 400.25 or higher, since the seasonal correction for January is -0.25.

[wili]

"When will the seasonally corrected monthly mean at Mauna Loa reach 400?"

Probably this month.

[JimD]

Crandles

Good points.  Lots of ways to look at it. 

[Pmt111500]

Lasst two twitter entries by Keeling curve,
Keeling_Curve @Keeling_curve  ·  7 t 7 tuntia sitten
400.06 parts per million (ppm) CO2 in air 08-Jan-2015 http://keelingcurve.ucsd.edu/
Keeling_Curve @Keeling_curve  ·  8. tammikuuta
400.01 parts per million (ppm) CO2 in air 07-Jan-2015 http://keelingcurve.ucsd.edu/

[Jim]

Here's my quick'n'dirty extrapolation for CO² levels.

We get the monthly mean exceeding 400 ppm by the middle of this year, and the last sub-400 ppm actual values by the summer of 2016. We will almost certainly never again see sub-400 ppm values in our (or our childrens) lifetime!