From CSIRO:
“What we learned is that in spite of droughts, floods, volcano eruptions, El Niño and other events, the Earth system has been remarkably consistent in regulating the inter-annual variations in atmospheric carbon dioxide levels,”
Tropical ecosystems regulate variations in Earth’s carbon dioxide levels
Rising temperatures, influenced by natural events such as El Niño, have a corresponding increase in the release of carbon dioxide from tropical forest ecosystems, according to a new study out today.
The study, published in the journal Proceedings of the National Academy of Sciences, found that a temperature anomaly of just 1ºC (in near surface air temperatures in the tropics) leads to a 3.5-Petagram (billion tonnes of carbon) anomaly in the annual CO2 growth rate, on average. This is the equivalent of 1/3 of the annual global emissions from the combustion of fossil fuels and deforestation together.
Importantly, the NASA Earth Exchange (NEX) study results provide scientists with a new diagnostic tool to understand the global carbon cycle as it undergoes major changes due to the influences of human activities.
NASA study co-author, CSIRO’s Dr Pep Canadell, said that the study’s 50-year analysis centred on temperature and rainfall patterns during El Niño years, when temperatures increase in tropical regions and rainfall decreases. An accompanying analysis assessed the effects of volcanic eruptions, which lead to decreased temperatures due to volcanic aerosols in the atmosphere.
“Our study indicates that carbon exchanges in tropical ecosystems are extremely sensitive to temperature, and they respond with the release of emissions when warmer temperatures occur”.
“Many processes involved in this response are the same as what is known as the carbon-climate feedback, which it is thought will lead to an acceleration of carbon emissions from vegetation and soils and into the atmosphere under future climate change.
“The observed temperature changes are more important than changes in rainfall in influencing concentration of atmospheric CO2“.
“Warming is the one thing that we know with most certainty will occur under climate change in the tropics, but there are still large uncertainties about the future precipitation in tropical regions,” says Dr Canadell, who is also Executive Director of the Canberra-based Global Carbon Project.
“What we have is a strong and robust coupling between seasonal variations in atmospheric CO2 growth and tropical temperatures over the past 50 years and this provides us with a key diagnostic tool to assist in our understanding of the global carbon cycle,” he said.
The team, led by Dr Weile Wang, analysed widely available data on atmospheric carbon dioxide concentration and global air temperature between 1959 and 2011.
“What we learned is that in spite of droughts, floods, volcano eruptions, El Niño and other events, the Earth system has been remarkably consistent in regulating the inter-annual variations in atmospheric carbon dioxide levels,” said Dr Weile Wang, lead author of the paper.
The team used the NEX platform to analyse outputs from several global dynamic vegetation models to understand the mechanisms underlying the persistent coupling and the role of tropical ecosystems in the observed coupling.
The study highlights the importance of long-term observations of temperature and carbon dioxide, simple yet crucial, for improving our understanding of the Earth system.
What they found was, unlike in other parts of the planet, year-to-year changes in temperature over the tropics act in concert on both photosynthesis (absorption of carbon dioxide) and respiration (release of carbon dioxide), the two important mechanisms that naturally regulate year-to-year changes in atmospheric carbon dioxide concentrations.
“For example, a rise in temperature over the tropical regions results in a decline in photosynthesis as well as an increase in carbon losses through respiration, amplifying the temperature effect on carbon cycling” says Rama Nemani, Principal scientist for the NEX project.
The study highlights the importance of long-term observations of temperature and carbon dioxide, simple yet crucial, for improving our understanding of the Earth system.
The study was supported by NASA’s Earth Exchange project, the Australian Climate Change Science Program, and the Global Carbon Project.
Read more media releases in our Media section.
Wang A, Ciaisc P, Nemanid RR, Canadelle JG, Piaof S, Sitch S, Whitei MA, Hashimotoa H, Milesia C, Mynenij RB. 2013. Variations in atmospheric CO2 growth rates coupled with tropical temperature. Proceedings of the National Academy of Sciences.
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Here is a piece from Viv Forbes blog, by a teacher of horticulture. A worthy lesson in perception and facts.
“I have come to understand that few people actually have any concept of what 350 ppm and 400 ppm or 700 ppm actually means. I teach horticulture, and in a recent class on the role of co2 in photosynthesis, the usual ” we are all all going to die” statements began.
On the the white board, I drew a square with 1 meter sides, and invited the students to show what they understood to be 400 ppm, the current concentration of co2 in the atmosphere, in this square.
I was astonished to see that half to three quarters of the square was seen as 400 ppm.
As result, I asked the group, how many millimetres are in a square metre. I was staggered to find most had no idea.
Carefully, so as to avoid offending people, I explained that there are 1,000,000 mm2 in a square metre, (1000 x1000 = 1,000,000. Then I drew a square with 20 mm sides and said this is 400 mm2, or 400ppm, there was dead silence. Then I drew a square with 4mm sides and said this represent the 4 % that human activity is generally considered to contribute, and what is claimed to control our climate.
There was more silence followed by angry statements, of how that could be possible, have we been lied to, it does not make sense, and further statements of enlightenment.
This was the most success I have had in trying to get people to understand that CAGW is rubbish, and it felt good”.
More sound and fury signifying nothing.
They have such small numbers of non-random, non-replicated field observations (my guess is that ALL of a pitiful number of site observations equal n=1) that any pretense that data drawn from them applies generally to the ‘tropics’, the entire biome-area they are in, or the rest of the globe for that matter, are absurd.
By all means enlighten me.
A colleague emailed me this link (“Adrift”), showing fog moving into and out of San Francisco Bay. My first reaction was to think to all those enamored with models, “Model This”.
Warming will reduce photosynthesis in the tropics? Oh, reaally?
Increase of CO2 concentration reduces transpiration requirements. Maybe that’s what got them confuzed.
The atmosphere, especially our favorite part, oxygen, are entirely the result of life. ALL the 20% O2 was once part of CO2 that had its C stolen by plants to make fancy molecules. That we then eat.
If, eg, a huge GCR burst were to sterilize the planet tomorrow, by next year there would be little or no free O2. It was all once part of CO2, which has been eaten down to traces by infinitely greedy plants. IMO, it’s our assigned role and duty to boost the return leg of the cycle by de-sequestering it from the geology where plants and plankton stashed it.
@ur momisugly Gerry Parker – absolutely right well said!
But are they perhaps also offernig an explaination of why CO2 levels lag temperature?
Bart says:
July 23, 2013 at 2:29 pm
///////////////////////
Bart
It appears to fit but for a blip around 1993 when the derivative drops significantly but temperatures do not.
Any explanations/theories for this discrepancy?
“The team used the NEX platform to analyse outputs from several global dynamic vegetation models to understand the mechanisms underlying the persistent coupling and the role of tropical ecosystems in the observed coupling.”
Computer model outputs were the inputs to this study?
“The study highlights the importance of long-term observations of temperature and carbon dioxide, simple yet crucial, for improving our understanding of the Earth system.”
This was a LOL statement for me.
“CSIRO:
“What we learned is that in spite of droughts, floods, volcano eruptions, El Niño and other events, the Earth system has been remarkably consistent in regulating the inter-annual variations in atmospheric carbon dioxide levels,””
Given the group used computer model outputs as inputs to the study, this statement is pure politics. What they mean is that any change to CO2 levels, primarily from human emissions, outside that “consistent inter-annual” variation will lead to instability in climate. Or “climate disruption”, it’s the new scare du jour!
Another set of claims built on guesses,cherry picking etc.. Temperatures are not certain to increase in the tropics, that is a guess built on poor models. We do not know for certain the exact CO2 budget and exchanges so those are also guesses.
Brian H,
“ALL the 20% O2 was once part of CO2 that had its C stolen by plants to make fancy molecules.”
= = =
Correction: All the O2 was once part of H2O that had its H stolen to make carbohydrates.
“Khwarizmi says:
July 24, 2013 at 5:52 am”
Those inconvenient bar stewards.
I am not sure why this is news. All biochemists know that metabolism of all organisms goes up with temperature. The rule of thumb in marine biology is that metabolic rates triple for every 10 deg C increase in water temperature. It makes complete sense that an ecosystem’s overall “holometabolism” would go up with warming of the climate.
richard verney says:
July 24, 2013 at 12:14 am
“It appears to fit but for a blip around 1993 when the derivative drops significantly but temperatures do not. Any explanations/theories for this discrepancy?
Pinatubo.
And here is …. Dr. Murry Salby! to speak for himself and show why the above article is only partly correct and why F. Englebeen is almost completely mistaken.
Hamburg, Germany, 4/18/13
Janice Moore says:
July 24, 2013 at 11:16 am
And here is …. Dr. Murry Salby! to speak for himself and show why the above article is only partly correct and why F. Englebeen is almost completely mistaken.
Except that Dr. Salby is completely mistaken on several points, which I have responded to here and following.
– The source of low 12CO2 is not from current vegetation, as current vegetation is a net sink for CO2, thus preferentially of 12CO2, leaving relative more 13CO2 in the atmosphere.
But we see an enromous decline of 12CO2 in the atmosphere.
– The return of 14CO2 from vegetation is slightly lagging the 14CO2 levels in the atmosphere, but 14CO2 levels from fossil fuels are zero, leading to additional drops in 14CO2 of the atmosphere.
– There is little migration of CO2 in relative “warm” ice cores, leading to some small broadening of the resolution (20 to 22 years at medium depth, up to 40 years at full depth) virtually absent in the colder inland ice cores. According to Salby, a change of 1000 ppmv 100 kyrs ago may be hidden due to some theoretical migration, not based on any real measurement. But he forgets that such a peak must be compensated by a similar drop in CO2 levels to maintain the average, as the average is not influenced over the resolution period. A little difficult if the average is 180 ppmv over a period of 90,000 years…
Ferdinand Engelbeen says:
July 24, 2013 at 12:57 pm
“According to Salby, a change of 1000 ppmv 100 kyrs ago may be hidden due to some theoretical migration, not based on any real measurement.”
Not so. Salby showed, in considerable detail, how the measurements were consistent with CO2 migration.
“But we see an enromous decline of 12CO2 in the atmosphere.”
We see a small decline, and it varies with temperature, too.
Bart says:
July 24, 2013 at 2:22 pm
Not so. Salby showed, in considerable detail, how the measurements were consistent with CO2 migration.
He calculated the migration as result of his theory what the measurements should be, not of what they were and didn’t take into account the different resolutions of different ice cores with huge differences in accumulation. Then he only mentions that a measurement of a 100 ppmv “peak” over an interglacial (at 280 ppmv) in (his) “reality” may have been a 1000 ppmv peak. But as that was over 10% of the time, in the other 90% of the full 100 kyear time, the 180 ppmv measured thus in “reality” would be below 80 ppmv. Where all plant life on land would have died…
Further, if there was such a huge migration, that doesn’t stop after 100 kyears. It goes on for every glacial/interglacial transition back in time. Thus decreasing the 1000 ppmv peak at the first interglacial to 100 ppmv, then to 10 ppmv then to 1 ppmv…
But there is not the slightest decrease in CO2/temperature ratio measurable over 800 kyear…
“But we see an enromous decline of 12CO2 in the atmosphere.”
We see a small decline, and it varies with temperature, too.
The decline in 13C/12C ratio (12CO2 was a typo of mine, it is 13CO2 which is declining) during glacial-interglacial transitions as measured in ice cores is a few tenths of a per mil. The natural variability over the Holocene was +/- 0.2 per mil with little to no trend (measured in ice cores with a resolution of 8-40 years and in ocean waters by sponges over the past 600 years with a resolution of 2-4 years). The current drop since ~1850 is 1.6 per mil, four times the natural variability over 800 kyear… I think I may call that enormous.
See: http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.gif
Further, I had quite a lot of comment on Dr. Spencer’s work at that WUWT page…
Ferdinand Engelbeen says:
July 24, 2013 at 3:23 pm
“Where all plant life on land would have died…Thus decreasing the 1000 ppmv peak at the first interglacial to 100 ppmv, then to 10 ppmv then to 1 ppmv…”
This is not how filtering processes work. Low pass filtering never takes out the dc component, and a peak at a particular frequency is only taken out once, while other peaks in the passband are largely unaffected.
“The current drop since ~1850 is 1.6 per mil, four times the natural variability over 800 kyear…”
Again, assuming a quality of historical measurements which cannot be independently verified.
Bart says:
July 24, 2013 at 5:49 pm
This is not how filtering processes work. Low pass filtering never takes out the dc component, and a peak at a particular frequency is only taken out once, while other peaks in the passband are largely unaffected.
Migration in the firn before the pores are fully closed is what gives the (assymetric) filtering of several years (10 to 600 years) in ice cores. The resolution only depends of the accumulation speed and temperature, as that gives the speed of blocking further gas exchanges via the pores and ultimately full closure. See Fig.11 at:
http://courses.washington.edu/proxies/GHG.pdf
Thus any one year peak of 20 ppmv or any sustained increase of 2 ppmv over 10 years would be detected in the fast accumulating ice cores of Law Dome (accuracy ~1.2 ppmv, 1 sigma). Even the current one-sided 100 ppmv increase over 160 years would be detected within the 560 or 600 years resolution of the Dome C (800 kyr) or Vostok (420 kyr) ice cores. If it was part of a full cycle, it still would be detected as the increase speed still is not decellerating, thus the full cycle is longer than 600 years…
Dr. Salby didn’t take into account the differences in accumulation and hence resolution of the different ice cores…
Migration of CO2 in ice is the distribution of high peaks over lower levels over time. That is only affected by the difference in CO2 level and time. Given sufficient time, that will level all differences. Thus a 10x drop in peak against a “baseline” of 180 ppmv over 100 kyrs will get a 100x drop over 200 kyrs, etc.
It is not clear to me to which of the two migration paths Dr. Salby alludes in his calculations, but for both pathways he is way out of reality…
Bart says:
July 24, 2013 at 5:49 pm
Again, assuming a quality of historical measurements which cannot be independently verified.
In the case of 13C/12C ratio’s, the data are independently verified in tree wood (and leaves), ice cores and coralline sponges. The latter of course in water, not in air, but there is a huge, fast exchange of CO2 (including all isotopes) between the surface waters where coralline sponges grow (down to 200 m depth) and the atmosphere (coralline sponges d13C follows air changes with a delay of 2-3 years). Taking into account the fractionation at the air-water border, that gives a third confirmation of the 13C/12C changes over time.
Ferdinand Engelbeen says:
July 25, 2013 at 5:58 am
Salby’s methodology is sound.
Ferdinand Engelbeen says:
July 25, 2013 at 9:26 am
Even if I accept this with no references or explanation of methodology, these are all subject to aging effects. There is no closed-loop experiment possible where you inject the isotopes in, and measure them eons later.
You are rationalizing, and hanging your hopes on what is merely consistent with your narrative. But, consistency is not proof, and the most recent, reliable, and verifiable evidence says your narrative is wrong.
I think that’s about it for now. Take care until we meet again…