CO2 – The View From Space – update

Joint post with Erik Swenson who studied computational physics and is based in California.

OCO-2 is NASA’s latest and most advanced instrument for measuring the distribution of CO2 from space. Launched in July 2014, NASA published a map in January of this year summarising data from 1 October to 11 November 2014 that I covered in a post titled  CO2 – The View From Space. But then there has been several months of silence.

The silence was broken recently when NASA dumped a year of OCO2 data onto one of their servers. They have not provided fresh maps, just raw data in a format not accessible to the layman. Erik Swenson writing at WUWT has accessed and processed the data and produced a series of maps which tell an interesting story.

A good starting point is to look at one of Erik’s maps for a 52 week average of data and compare this with global forest cover. The 52 week average is understood to provide a picture of net sources and sinks of CO2 (upper map). Many of the net sources appear to correlate with global forest cover (lower map) which is counter to intuition that global forests have acted as a net sink for anthropogenic CO2.

Forest map from the Japanese Space Agency

I want to try and keep this post short and simple so that many can follow the story, but that in itself is a challenge. The first task will be a brief examination of quality control.  How do we know Erik’s maps, based on the NASA data, are reliable? The second task will be a few comments on the carbon cycle and the HUGE upheavals in CO2 around the globe across the annual cycle, that, when averaged give rise to the ordered net sources and sinks map shown at the top of this post. The third task will be to make observations about the net sources and sinks and to speculate about what these observations might mean.

Task 1: Data Quality

There are two important aspects of data quality. The first is what NASA measures from space and how reliable this represents CO2 in the atmosphere. The second is how reliably Erik has managed to capture this data and project it into the maps he has produced. The data are acquired by a polar orbiting satellite and because of various physical limitations, the data N and S of 60˚ are less reliable than the data between these latitudes. NASA has released two data sets. The OCO2 LITE data, that Erik has used, is regarded as the most reliable.

In his WUWT article, Erik was very obliging in responding to requests. And one request I made was that he produce a map for 1 October to November 11 2014 on comparable scale to that previously published by NASA. Below are Erik’s (upper) and NASA’s (lower) maps:

There is a high degree of correspondence between the two but also some discrepancies, most notably in the N Atlantic and N Pacific. The areas of agreement are sufficiently good to warrant Erik’s methodology is good. The areas of discrepancy are most likely explained by different versions of input data being used.

Task 2: CO2 Convulsions Across the Annual Carbon Cycle.

The maps below each summarise 6 weeks of data, the minimum time required for the satellite to gather representative global cover. This also follows the NASA convention. Erik produced 8 such maps for 8 time slices which can be viewed at WUWT and at the end of this post. Note that the scale bars have been changed on the maps below relative to those published on WUWT (an error was found that has since been corrected). The picture is very complex and in interest of trying to simplify this I show only 4 maps below. My instinct was to show the maps that spanned the winter solstice, spring equinox etc. But it is in fact the maps in between these seasonal markers that show the more extreme behaviour that I have shown below. NH = northern hemisphere.

1 October to 11 November = NH Autumn
1 January to 15 February = NH Winter
1 April to 15 May = NH Spring
1 July to 15 August = NH Summer

If you are struggling to make sense of the maps, don’t worry, I think everyone will be. But as a starting point, it is important to appreciate the enormous natural CO2 fluxes involved.

The IPCC and climate science community accept that annual manmade emissions are tiny compared with the natural fluxes and stores. It is unlikely that a single year of OCO2 data would show any emissions CO2 against such a large natural flux.

Task 3: Observations and Interpretation

A good starting point for the discussion is to compare the 4 time slices with the Mauna Loa CO2 data. The annual cycle at Mauna Loa has long been linked to photosynthesis, a hypothesis that has never made complete sense to me. The mosaic below rationalises the OCO2 maps with atmospheric observations. But it is less easy to link the observations to biological and natural processes.

It is convenient to begin the discussion with the 1 April to 15 May NH Spring time slice (lower left quadrant labelled May). This shows the NH “awash with CO2”. The SH in Autumn is largely neutral. The NH highest concentrations are over the rain forests of the Amazon and Congo, SE Asia and above the Boreal forests of Canada and Russia. Alarmists may want to imagine elevated CO2 over E United States, Europe, India and China. But manmade emissions are tiny compared with the natural flux and should be in decline at this time of year. I would not expect manmade emissions to be visible.

In this time slice the NH growing season is just getting under way and one may have expected plant growth to be drawing down CO2 while the opposite is clearly happening. I will hypothesise that we are observing soil processes and decay of organic matter. This could be linked to trees pumping organic acids into soils or microbial activity. It is more than a little curious that the tropical forests N of the Equator also pulse CO2 at this time since they lack a seasonal driver. Taking a step back to the 1 January to 15 February time slice (top right) we see that the pulse of NH forest emissions begins in mid-winter.

I am happy to entertain other ideas from informed commenters. Elevated CO2 over the NH oceans I will assume is linked to circulation from processes taking place over the forests.

Moving on to the next time slice, 1 July to 15 August (NH Summer, bottom right) we see a very dramatic change where the high latitude Boreal forests turn from source into sink pumping down atmospheric CO2. This can be reconciled by photosynthesis and tree growth. Notably the tropical forests of the NH are largely neutral at this time. This time slice represents the depths of the SH hemisphere winter and while much of the land is neutral, the southern Ocean has turned into a net CO2 source, counter to the intuition that cold water should absorb more CO2.

The 1 October to 11 November time slice (NH Autumn, SH Spring, top left labelled Nov) shows a time of CO2 sequestration across the globe, consistent with the low point of the Mauna Loa cycle. CO2 is evidently being pumped down by high and low latitude oceans. But a surprising observation is reduced CO2 over or close to many of the Earth’s deserts. I am unable to offer an explanation.

To conclude I return to the 52 week summary map posted at the top of this post. Below I have added numbers to the main features that are described below.

  1. Much of the land and ocean area is coloured green reflecting that it is neither a net source or sink. Considering the annual carbon cycle convulsions described above, this is somewhat surprising but also gives a sense of security in data quality.
  2. The SH on average appears to be neutral with some positive and some negative residuals.
  3. Large segments of the NH are shaded neutral green but the forested land masses appear to be a major net source of CO2
  4. The global thermohaline circulation emerges in the N Pacific to the S of Alaska and this positive residual may be linked to the emergence of deep, carbon rich, low pH ocean water.
  5. The tropical forests of the Amazon and west central Africa are a net source of CO2.
  6. The tropical forests of SE Asia, China, Korea and Japan are a significant net source of CO2.
  7. The Boreal forests of Canada and the eastern seaboard forests of the USA are a significant net source of CO2.
  8. Elevated residuals over the N Atlantic and N Pacific have the appearance of offshore plumes sourced from the onshore forests.
  9. The southern continental extremities of S America, Africa and Australia appear as minor net sinks for CO2.
  10. The high latitude southern ocean appears to be a net sink for CO2.

I realise that many readers will be looking at positive residuals over the eastern USA, Europe, China, S Korea and Japan and be thinking that this must be proof positive of manmade emissions. Here, socio-economic history plays a cruel trick. Before we started using coal, industrial society was rooted in the areas where there was ample timber. The forest cover map up top shows that the eastern USA, Europe, China, S Korea and Japan are all heavily forested. The correlation here is with forest cover and not with Man. The positive residuals in the Amazon, Congo and over the Boreal forests show this to be the case. And the absence of residuals over much of the USA, S Africa, The Middle East, SE Australia and India shows that industrialised areas away from forests do not have positive residuals. The populated and industrialised areas of coastal Brazil have a neutral residual while the deep Amazon Forest appears as a net source.

To hammer home the point about the link between positive residuals and forest cover, the map below shows the two overlaid. I got lucky with the map projections which are exactly the same.

It goes beyond the scope of this post to try and explain why global forests appear to be a net source of CO2. This implies the forests are out of equilibrium. This may be linked to natural climate cycles and it would not surprise me in the least if forests go through cycles of sequestering and then emitting CO2. This does not necessarily mean that the forest mass is decreasing since it is possible that the CO2 is linked to soils. There is a large amount of research required to understand exactly what is going on and the addition of further data may assist this understanding. But OCO-2 is only scheduled to acquire data for two years.


This post is prepared in good faith based on the assumptions that the input data and Erik Swenson’s maps are accurate and reflect the dynamics of CO2 sources and sinks. If one of these three assumptions fails then we reserve the right to withdraw all of this commentary.


All the available maps are given below for reference purposes.

1 Oct to 11 Nov 2014
16 Nov to 31 Dec 2014
1 Jan to 15 Feb 2015
16 Feb to 31 Mar 2015
1 April to 15 May
16 May to 30 Jun 2015
1 July to 15 aug 2015
16 Aug to 22 Sep 2015

This entry was posted in Climate change and tagged , , , , , , . Bookmark the permalink.

38 Responses to CO2 – The View From Space – update

  1. Leo Smth says:

    Just a thought:

    What determines if the decay of organic matter from trees etc ends up as sequestered carbon, or free atmospheric carbon?

    One could conjecture that species that, when they die, release CO2 into the air would be giving up a valuable nutrient to their descendants. In a CO2 poor world. Species that squandered CO2 and turned it into coal might have survived and prospered in an early CO2 rich climate.

    We know that the places where carbon is sequestered are not forests, but bogs. Dead organic material in anaerobic environments forms peat, the precursor to coal. Where bogs are drained (the UK Fens) the land level drops due to oxidation over decades.

    Likewise we suspect that oil is from dead organic material on sea floors.

    Which is to say in an oxygen rich environment, you dont get sequestered carbon except when shielded from oxygen. Like underwater or underground.

    Maybe tee CO2 rise is all about man made elimination of wetlands…;-)

    Hey, it’s no more crazy a hypothesis than positive feedback amplifying CO2 radiative effects 😉

    • Euan Mearns says:

      We know that the places where carbon is sequestered are not forests, but bogs.

      Geologically, bogs on land stand a poor chance of surviving and being delivered into the fossil record. The main environment where continental organic carbon is sequestered is on river deltas and offshore river deltas. These coastal areas are going down, so successive layers of sediment bury what went before. Marine organic matter, mainly dead plankton, accumulate in anaerobic mud on the ocean floor. The other sink for carbon is carbonates made either by shelly organisms are by direct precipitation in shallow tropical seas.

  2. Joe Public says:

    Thanks to you both, for a fascinating insight.

  3. Leroy Essek says:

    Here in California there has been a high percentage of man made elimination of wetlands. The largest lake in California (international bird sanctuary) is being drained to access the largest geothermal energy field. The geothermal brine also contains billions of dollars of lithium, precious metals and other highly profitable minerals. Hundreds of active environmentalist (past and present) going as far back as President Jimmy Carter are trying to restore the Salton Sea by using a unlimited supply of ocean water from the Sea Of Cortez. The independent research to pay for the Sea to Sea Solution is approx. one billion dollars. The Salton Sea Authority (who is the kitten guarding the milk) is asking the State and Federal taxpayers to fund a nonrefundable 3.1 billion dollar mitigation plan to turn the Salton Sea into a ecofriendly geothermal powered mudpuddle.

    • Owen says:

      Shocking if true, isnt there a water shortage in California so draining their largest lake would not be the smartest decision (aside from the environmental damage)

  4. marchesarosa says:

    The fact that CO2 emissions are high over forests would seem to suggest tree respiration. Like most living things, trees “inhale” oxygen and “exhale” carbon dioxide. Maybe biologists have just underestimated the exhalations of CO2 relative to the consumption via photosynthesis?

    The images above certainly need a lot of explaining.

    • Euan Mearns says:

      I tend to view this from the perspective of equilibrium. We know there are annual growing cycles in forest, especially high latitude forests with strong seasonality. If a forest is in equilibrium, like the Indonesian tropical forests appear to be, then CO2 “exhaled” should match CO2 inhaled over the annual cycle the net effect should be zero residual.

      The presence of a net positive residual suggests that over the annual cycle the forest is releasing more CO2 than it is inhaling and converting to wood. The surplus CO2 may be coming from accumulated organic debris on the forest floor or from the soils as opposed to trees falling over and dying today.

      • Nador says:

        Do we know if forests can increase the erosion of e.g. limestone – thus releasing co2 ? Increased acidity due to decomposing material might help in dissolving limestone formations. Do forests with limestone bedrock emit more co2 than ones with volcanic bedrock?

        • A C Osborn says:

          Insect activity also needs to be looked at with regards to Forest areas.
          Termites are a known source, but what about Ants.

    • Javier says:

      The hypothesis is that the increase in CO2 accelerates tree renewal, so in our high CO2 atmosphere trees grow faster but they also die faster and since young trees contain less CO2 than old trees, forests have become a net source of CO2. There is evidence showing this and several papers published on it over the last years, since it was discovered that forests were a CO2 source despite the fertilization effect of CO2.

      I have read a couple of those papers but I remain skeptical of the finding. In my opinion it is the type of “ad hoc” science that it is practiced these days and researchers have failed in their due diligence to examine alternative explanations, specially soil biology. A more productive forest could easily have a more productive soil that releases more carbon stored in the soil. The soil capacity to store carbon is amazing. According to Freeman Dyson, the growth of soil biomass by a hundredth of an inch annually would stop CO2 increase completely. Such capacity to store it is matched by the capacity to release it if conditions are adequate.

  5. Javier says:

    OCO-2 has no interesting information for the general public. The annual changes in CO2 are quite well known since the 70s. The derivative of the monthly CO2 change is equal to the change of global temperature with a slight delay of a few months. This has been argued all over internet multiple times since it leads to much confusion with some prominent skeptics mistakenly believing that it proves that temperature changes are the cause of the CO2 interannual increase. It actually means that the main annual changes in CO2 sinks and sources are by far of biological origin, both at land and sea (marine microorganisms). There is nothing really more about it. CO2 is quite well mixed with a slight gradient North to South due to main production in the Northern Hemisphere so that Antarctica has about 20 ppm less than global average.

    There is really no doubt that the increase in CO2 since the 50’s is of anthropogenic origin, but there are two very interesting questions that nobody can answer to my knowledge:

    1) Global sink capacity has grown every year to match almost exactly 45% of anthropogenic CO2 production. Nobody knows why it grows at the exact rate to remove a constant fraction of human CO2 increase, since human increase is a very small part of yearly CO2 flux.

    2) During most of the Holocene since 7000 yr BP to about 200 yr BP global temperatures have been going down while CO2 levels have been going up. There are different hypothesis for why CO2 levels have been going up, but to my knowledge nobody has explained satisfactorily how it is possible that temperatures have been going down against such increase in CO2. It is not insignificant. The entire glacial termination was a change from 195 to 265 ppm CO2 (+70 ppm), and the last 7 kyr Holocene change is from 260 to 285 ppm CO2 (+25 ppm), almost a third of the glacial termination changes in logarithmic scale. GCMs are unable to model such a fall of temperatures in the face of such an increase in CO2 because of the assigned forcing to CO2 in modern industrial times. This problem was named the Holocene temperature conundrum in a recent paper in PNAS.

    AGW sites refuse to discuss this problem and AGW proponents keep quiet about it. They defend that Holocene CO2 changes are small compared to modern changes and therefore other forcings, specially solar forcings dominate. This is not true. While small compared to modern changes, they are not small compared to glacial termination. Glacial termination is believed to have caused a 4-5°C increase in global mean temperature, with the 70 ppm increase in CO2 being responsible for 1/3 to 1/2 of that increase. Holocene global temperature drop since climatic optimum is believed to be 0.5-1.5°C at most, so an increase of 25 ppm CO2 should have prevented most of that drop. The alternative is that we do not understand Holocene climate and that the real temperature drop without CO2 increase should have put us back into glacial conditions thousands of years ago. This is the basis for the Ruddiman early anthropocene hypothesis that is emphatically rejected by most Holocene CO2 experts. The hypothesis defends a human cause for the early Holocene increase in CO2, but appears really weak at the light of CO2 budget calculations and sources contributions due to Holocene known changes in insolation and SST. The increase in CO2 is easily explained as a biological response to climate deterioration plus oceanic responses.

    • Global sink capacity has grown every year to match almost exactly 45% of anthropogenic CO2 production. Nobody knows why it grows at the exact rate to remove a constant fraction of human CO2 increase, since human increase is a very small part of yearly CO2 flux.

      This can be explained simply by assuming a ~30 year atmospheric residence time – or more correctly half-life – for anthropogenic CO2 emitted to the atmosphere, as discussed in this earlier post:

      • Javier says:

        Neat curve fitting exercise, Roger. I wonder if it can be tested somehow, or derived by a completely independent way.

        It bothers me however that half-life is a constant over six decades, not only in your model, but in everybody else’s. That assumes that the balance between sinks and sources is also a constant when we know that both change with time, temperature and who knows what else. This is not a radioactive decay type of half life. If sinks decrease relative to sources half-life should increase and vice versa.

        Perhaps they don’t change enough or they change in parallel.

        Most CO2 climatologists assume that if we had not put any CO2 on the atmosphere the levels would remain the same as pre-industrial and the temperatures would have not changed. Such ecstatic view contradicts everything we know about Holocene climate variability. Stomata CO2 proxies paint a very different picture to the low band pass filter that CO2 trapping into ice-cores constitutes.

        Stomata CO2 evidence is complex but hints at a very different level of past CO2 variability. It is not very scientific to have two lines of contradictory evidence and decide to ignore one and completely trust the other.

        If stomata data is correct, modern global warming should have produced quite a lot of natural CO2 changes in the background, so anthropogenic increase would be lower and natural increase higher and everybody’s calculations would be over-estimating anthropogenic CO2 levels and half-life.

  6. Euan: This is more like a post than a comment – you can think of it as “CO2 – The View From The Ground” if you like. It presents data from ground CO2 flask measurements that provide some additional insights into how CO2 behaves in the atmosphere and which hopefully will assist in the interpretation of the maps you present. No earth-shattering conclusions are reached.

    CO2 concentrations are higher in the Northern Hemisphere:

    Figure 1 plots annual smoothed averages of CO2 flask readings at ten land stations extending from the High Arctic to the South Pole (data from Scripps). Stations in high northern latitudes are colored in reds and stations at high southern latitudes in blues (the deep red line is Point Barrow at 71 degrees north and the deep blue line is the South Pole). We see that CO2 concentrations in high northern latitudes are consistently four of five ppm higher than CO2 concentrations in high southern latitudes:

    Figure 1: Annual smoothed averages, ten CO2 measurement stations between High Arctic and South Pole

    Figure 2 plots ppm CO2 measured at 68 land stations averaged over the one-year period from October 1, 1995 through September 30, 1996 against latitude (adding 40ppm will bring the values to within a few ppm of present-day values). The plot can be divided into four segments:

    South of latitude 40S: CO2 concentrations are quite consistent and average 359.3 ppm.
    Between 40S and ~15N: CO2 concentrations increase.
    Between ~15N and 60N: CO2 concentrations average 363.4ppm but become erratic – probably because this latitude band contains most of the Earth’s landmasses.
    North of 60N: CO2 concentrations remain at about the same level but variability decreases.

    Figure 2: Annual average CO2 vs. latitude at 68 measurement stations, 10/1995 through 9/1996

    We can conclude from these two Figures that the source that’s causing atmospheric CO2 to increase, be it anthropogenic or natural, is in the NH. The CO2 it adds to the atmosphere mixes rapidly in the NH but takes a couple of years to find its way across the ITCZ into the SH.

    The amplitude of the seasonal CO2 cycle is much higher in the Northern Hemisphere:

    Figure 3, which plots the amplitude of the 1995/96 seasonal cycle at the 68 station against latitude, shows a picture similar to Figure 2. Seasonal cycle amplitudes below latitude 30S are on the order of only 1ppm, but between 30S and ~45N they increase rapidly to 14-15ppm before flattening out:

    Figure 3: Amplitude of seasonal CO2 cycle vs. latitude at 68 measurement stations, 10/1995 through 9/1996

    There are two potential contributors to the seasonal CO2 cycle – vegetation growth/decay on land and CO2 release/absorption in the oceans. The fact that the cycles have high amplitudes in the NH where there is more land and low amplitudes in the SH where there is more ocean suggests that vegetation growth/decay and associated release/absorption by soils are the dominant influence.

    Figure 4, which superimposes seasonal ocean CO2 fluxes derived from the gridded Takahashi ocean carbon flux model further tends to confirm that seasonal ocean CO2 fluxes are too low to explain the large seasonal variations observed in the NH (details on how I constructed the blue line are available on request but are too complex to discuss here):

    Figure 4: Amplitude of seasonal CO2 cycle vs. latitude at 68 measurement stations, 10/1995 through 9/1996, ocean CO2 contribution from Takahashi gridded model shown in blue.

    Latitude also governs the timing of the seasonal cycle:

    Figures 5 and 6 show the months in which CO2 concentrations reach their maximum and minimum at the 68 stations. I’m sure these plots are telling us something but I haven’t quite figured out what it is yet.

    Figure 5: Month in which CO2 reaches its maximum value vs latitude at 68 measurement stations, 10/1995 through 9/1996 (note that December is either 12 or 0).

    Figure 6: Month in which CO2 reaches its minimum value vs latitude at 68 measurement stations, 10/1995 through 9/1996

    Finally comes the question of what triggers the seasonal change from CO2 emission to CO2 absorption. I’ve looked at this in detail only in the case of Point Barrow, and here the trigger is evident – Spring starts when the snow melts:

    Figure 7, daily CO2 readings for 2012 at Point Barrow, Alaska

    • Euan Mearns says:

      Roger, thanks for this. I also tried to avoid interpretations and conclusions. But it is thought provoking to see different plots. Figure 1 is interesting. Do the lines converge back in time? If so, can you regress the best data to get an intercept that would show when the NH and SH last had the same ppm CO2.

      If they don’t converge on a 200y time scale it would suggest that the NH has “always” had higher CO2.

      • Unfortunately we soon run out of data before 1975. But I’ll look into updating the plots to see if there’s any trend in the data between 1975 and 2015. Forty years of data should tell us something.

        There’s another puzzling feature in my earlier post on the terrestrial carbon sink.

        Particularly this Figure, which shows the amplitude of the seasonal CO2 cycle increasing at various NH stations.

        My original supposition was that these increases were caused by the growth of trees and other vegetation. But at Barrow and Alert there are no trees, and precious little vegetation either.

        • A C Osborn says:

          With regard to Barrow what sort of Actual PPM value are we talking?
          Could it have been increased by increasing human activity in the area?

  7. Erik Swenson says:

    Thanks Euan for publishing this. Hopefully this will spark some good conversations on what is going on with the OCO-2 data. It sure is interesting to look at and try to understand.

    • Euan Mearns says:

      Erik, THANK YOU for producing these wonderful maps. I’ve been blogging for many years, too long 🙁 But on past experience, its when folks with different skill sets come together that interesting things can come to pass. Roger has been looking at carbon cycle for many years through the geoscience lens and is re-posting some very interesting charts here that I had forgotten about. There are some answers in there somewhere.

      • Another piece of the puzzle. Having updated my data I find that the ppm difference in CO2 between the Arctic and Antarctic shows an increasing trend over the last 40 years (the difference between Barrow and the South Pole has increased from ~3.3ppm in 1975 to ~4.7ppm now.) I’m tempted to relate this to increasing NH emissions.

        • Euan Mearns says:

          A regression should show when the NH and SH were last the same. The back of my envelope suggests about 150 y ago. As Javier says, all the evidence points to FF emissions raising the baseline. Or did N hemisphere warming 150 years ago upset forest equilibrium?

          • I have two estimates that show the trend line crossing zero in the 1880s, i.e. about 130 years ago. I wouldn’t bet the farm on this date though.

          • Glad I didn’t bet the farm. The date is now 1947, based on the trend line through this plot of the differences (running annual means) between Mauna Loa and South Pole. 1947 is when man-made CO2 emissions started to skyrocket.

  8. E.J. Mohr says:

    Not sure if my comment was eaten. In any even,at the risk of repeating myself. If northern forests are a net emitters of CO2, via an unknown mechanism, we may have an answer to the change in the atmospheric C12/C13 ratio. If forests are the source then fossil fuels are not the sole cause of the change in atmospheric C12/C13 ratios. It’s interesting that there may be an unknown, at least so far, natural perturbation in carbon balance taking place in northern hemisphere forests. Much food for thought here – and what is the process and how have we missed it?

    • E.J. Mohr says:

      Just to add to this, and Euan can correct me if I’m wrong, but the map also shows the north Pacific and north Atlantic as sources. If this is due to deep water rising as mentioned then if memory serves the CO2 would be juvenile CO2 and would have a C12/C13 ratio that would have an abiotic signature. If so, we have a complicated picture with forests being the larger source since the whole atmosphere C12/C13 ratio is skewing in favour of a biological source.

    • Euan Mearns says:

      I believe much of the weak positive residuals over the N Atlantic and N Pacific are down to seaward drift of CO2 from the land masses.

      And in this post (link below) I concluded because of vast annual ocean atmosphere exchange that d13C in atmosphere tells us little to nothing about the provenance of the current CO2 in the atmosphere.

      The CO2 in the oceans is mainly derived from rotting plankton at depth which continuously drizzles down from the surface.

  9. Flocard says:

    I have a question which is related to the schematic diagram with the different CO2 components stock and flux (atmosphere, ocean, , plant decay, man made emissions).
    I have trouble understanding the green and blue arrows on this diagram. They are large; that I had already heard. What worries me is that they are pointing in only one direction (CO2 production)
    I understood that these large flux contributions (ocean and living phenomena except man burning fossil fuels) were more or less in equilibrium (at least when not additionally disturbed ny man). If that’s the case it should be fluxes both “from” and “to”.
    From a pedagogical point of view should not the blue and green arrows be pointed both ways to express this state of equilibrium ?
    I certainly can’t show such a diagram to students and tell them that the problem is the small black arrow at the right.

    • Euan Mearns says:

      Hubert, you are of course correct, but its a bit more complex than simply making the arrow go 2 ways. It might have been better to not use arrows at all. The main point is to show that emissions are small compared with the atmosphere reservoir and the natural fluxes. Emissions only take on significant mass if you accumulate over decades.

  10. aizolnai says:

    Very interesting post on a global scale (as are the comments LOL), have you considered NOAA’s AIRS-NRT (Atmospheric Infra Red Sensor in Near Real Time)? I used it to predic dust storms in Kuwait together w Esri Wind data
    But in add. to dust score there are ascending/descending SO2, CO data for the previous week from that you might find useful if you haven’t found this already LOL2

  11. thojak says:

    Highly interesting post, big thanks to you + commenters ! 🙂
    Sharing this on my Swedish FB-site.
    Brgds from the Bestcoast of Sweden.
    Thomas Jakobsson

  12. Peter Shaw says:

    Euan, Andrew, and Erik –
    A feast of data, which promises to falsify many plausible hypotheses – some my own. I’d thought that the Mauna Loa seasonal delay (~1 month) was the time for a change to traverse ½ the Pacific, but is the time from high latitude for zonally well-mixed air. Also, I’d hoped to see traces of where the MOC upwelling of CO2-rich water is, but that’s lost in the seasonal changes.

    As NASA has released this data-set “as-is”, can we assume it’s passed their technical tests, so is reporting something real? Has anyone any indication that it’s been taken up by (say) NOAA?

    Javier –
    You make good points, to which I’d add that warmer tropical water doesn’t explain higher CO2 in an interstadial on a >1k year timescale; I think there’s another source.

    Euan –
    When reproducing that elegant IPCC carbon-cycle schematic, you might consider adding a couple of comments:

    > No mention of mid-ocean ridge volcanoes (CO2 source) or off-ridge regional hydrothermal circulation (CO2 sink via basalt alteration); neither value well-constrained.

    > There’s something odd about the marine cycle. My understanding is that limestone skeleta and biomass separately settle (I assume 11 & 2 resp from Marine biota), then the biomass degrades to CO2 which redissolves the limestone at depth and produces the “acidic” upwelled Pacific waters. The CO2 of limestone origin should thus be shown returning to Surface ocean, not accumulating in Deep water (ie 101 should perhaps be 112).

    General comment: Settling marine biomass removes atmospheric CO2; production and settling of limestone adds it (each 1m of marine limestone represents ~1t/m2 CO2 released).

    We need new hypotheses, so I’ll stick my neck out –
    C-4 plants appear to have evolved to handle stadial conditions (~200 ppmv CO2). Have forests acquired the ability to stimulate local decay processes early, so the extra CO2 gets seasonal growth off to a good start? Once light-limited photosynthesis at high latitude reaches high gear, that temporary excess is removed (or more), causing the “wave” of excess to vanish.
    If you don’t like this, do propose better ;).

    • Euan Mearns says:

      Peter, interpreting the data is a major challenge. The concern of many will be that the CC community simply take the Spring map that shows the NH awash with CO2 and say “look at that”.

      There are two issues of data. One the full data set and the second a QCd data set. It is the latter “LITE” data that Erik has used with a warn level of 15 as the cut off. I’m not aware of any of the agencies venturing an interpretation yet.

      One problem with data acquisition is that the measurements are dependent upon daylight. Hence at high latitudes you cannot get a full annual cycle, and we only have a partial picture.

  13. climanrecon says:

    If this is truly “raw” data then might there be some non-uniformity simply from the variation in elevation around the globe (mountains having less CO2 above them than oceans)? If so some corrections will be needed to try and remove this effect, or maybe this has already been attempted by NASA.

  14. Aert Driessen says:

    A very interesting post that would give me much optimism if the interface between real science and politics is still intact. But is it? Getting a bit cynical in my old age, sorry! Keep up the good work guys!

  15. Pingback: AWED Energy & Environmental Newsletter: October 26, 2015 - Master Resource

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