Homeopathic Climatology

TL;DR:

The IPCC and most leading figures in the climate biz claim that "cumulative emissions," rather than the amount of CO2 in the atmosphere, determines CO2's warming effect. "Cumulative emissions" means the total of all anthropogenic CO2 emissions since the start of the industrial revolution, not the amount of CO2 remaining in the air (which is very different).

In other words, they say that CO2 still has just as much warming effect after it has been removed from the atmosphere as it had when it was still in the air. That is obviously nonsense.

Abstract:

Mankind is adding CO2 to the atmosphere (mostly from fossil fuels), at a rate of about +5 ppmv/year. That rate has been generally accelerating since at least the 1940s (but ultimately it will be limited by finite fossil fuel supplies).

"Nature" (by which we mean the net sum of all non-anthropogenic CO2 fluxes) is currently removing CO2 from the atmosphere, but not as quickly as mankind is adding it. Anthropogenic CO2 emissions currently exceed natural CO2 removals by about 2.5 ppmv/year. That's why the CO2 level is rising by about 5 - 2.5 = 2.5 ppmv/year.

The rate at which nature removes CO2 from the atmosphere (moving it into the oceans, biosphere, soils, etc.) is mainly determined by the atmospheric CO2 level. That rate accelerates by about one ppmv/year for every 50 ppmv rise in the atmospheric CO2 level.

So if human CO2 emissions were to continue at the current rate indefinitely, the atmospheric CO2 level could only rise by about another 50 × 2.5 = 125 ppmv before plateauing, because at that level our emission rate would be equaled by the increased rate of natural CO2 removal.

The TCRE (Transient Climate Response to cumulative carbon Emissions) / RCB (Remaining Carbon Budget) concept is based on the assumption that those removals don't matter, and that temperatures will continue to rise even if CO2 levels are no longer rising, or even if CO2 levels are falling, as long as anthropogenic CO2 emissions are not zero. It assumes that emissions alone determine the warming effect.

In other words, it assumes the mere memory of CO2 formerly in the air has as much warming effect as the CO2 which remains.

That's very similar to the "water memory" concept which is the basis of homeopathic medicine.

It's also essential to justify the "Net Zero" compaign.

Discussion:

Climate industry sources dwell on (and often exaggerate) positive (amplifying) climate feedbacks, and ignore most negative (stabilizing/attenuating) climate feedbacks, including an entire important category called "carbon cycle feedbacks," or "carbon feedbacks" for short.

Carbon feedbacks are overwhelmingly negative (stabilizing). When CO2 levels are rising (as they are now), negative carbon feedbacks are the "carbon sinks" which remove CO2 from the air at an accelerating pace.

The two most important carbon feedbacks are marine uptake and terrestrial "greening" & soil enrichment. They both accelerate approximately linearly as the CO2 level in the atmosphere rises, meaning that the higher the CO2 level rises, the faster those natural "carbon sinks" remove CO2 from the atmosphere:

Negative temperature feedbacks help stabilize the Earth's temperatures, and negative carbon feedbacks help stabilize the atmospheric CO2 level. Both matter.

W/r/t absorption of CO2 by water, the linearity is probably intuitively obvious: the more CO2 molecules there are in the air, the more frequent are their collisions with liquid water. It's actually more complicated than that, because of chemical and biological processes, but it's nevertheless approximately linear. The CO2 level in ocean surface water closely tracks the atmospheric CO2 level, and that in turn determines the rate at which carbon is carried into the ocean depths by thermohaline circulation and "marine snow."

Carbon uptake by the terrestrial biosphere is less obviously linear, but it we know from agronomy studies that "CO2 fertilization" enhances C3 plant growth nearly linearly to above 1000 ppmv. The plants which sequester most carbon (trees, sphagnum moss) are C3 plants, so that carbon feedback, too, is approximately linear:

https://sealevel.info/C3_and_C4_Pflanze_vs_CO2_Konzentration_en_1750_2023_linearity_highlighted3.png

   (click to enlarge)   

https://sealevel.info/Eldarica_pine_trees_vs_CO2.jpg

   (click to enlarge)   

Note that it's mainly the CO2 level in the atmosphere which determines the net natural CO2 removal rate. There are other things that affect it, like water temperatures, but those are minor:

"From what we understand about the underlying processes, uptake of atmospheric CO2 should react not to a change in emissions, but to a change in concentrations." (Knorr, 2009)

The rate at which the terrestrial biosphere removes CO2 from the atmosphere has been accelerating as the Earth "greens" and plant growth accelerates. In fact, the greening trend is so dramatic that NASA satellites can measure it from space:

https://www.nasa.gov/centers-and-facilities/goddard/carbon-dioxide-fertilization-greening-earth-study-finds/

https://www.youtube.com/watch?v=zOwHT8yS1XIRT

The sum of any two linear functions is also linear, so the net rate of natural CO2 removals from the atmosphere must also be an approximately linear function of the CO2 level in the atmosphere.

That's confirmed by the data. The linearity is obvious if you plot the net CO2 removal rate (calculated as the difference between anthropogenic emissions and the observed year-over-year change in CO2 level) vs. the atmospheric CO2 level, as in this graph:

https://sealevel.info/Global_Carbon_Budget_2023v1.1_with_removal_rate_plot4.png

   (Adapted from "Fig. 1" here; here's the spreadsheet.)   

Mankind is currently adding >5 ppmv of CO2 to the atmosphere every year. The best estimate, mostly from emission data, is that we're adding a total of about 5.2 ppmv (≅ 11 GtC ≅ 40 Gt CO2) per year, roughly 90% of it from fossil fuels. But, thanks to negative carbon feedbacks (natural carbon sinks), the CO2 growth rate in the atmosphere is only about half that rate: about 2½ ppmv/year.

The "climate science community" acknowledges the uptake of CO2 by the oceans and terrestrial biosphere. E.g., this is from the 2025 GCP report (except that I added the pink annotations):

https://sealevel.info/GCP2025_overview_annot3.png

   (click to enlarge)   

This is an excerpt from Table 5.1 in the AR6 WG1 report:

https://sealevel.info/AR6_WG1_Table_5.1_annot1_partial_carbon_flux_comparison2.png

Note how the estimated rate at which the oceans and terrestrial biosphere are removing CO2 from the air is accelerating as the CO2 level rises: 3.7 PgC/yr in the 1980s → 4.6 → 5.0 → 5.9 PgC/yr in the 2010s.

That's an acceleration in CO2 removal rate of 2.2 PgC/year in 30 years. Converting from PgC to ppmv (divide by 2.1294 PgC/ppmv) yields an acceleration in removal rate by just over 1.0 ppmv/year, as the CO2 level rose from 346 ppmv in 1985 to 401 ppmv in 2015. That corresponds to a CO2 removal rate acceleration of 0.945 ppmv/year per 50 ppmv rise in CO2 level, implying an adjustment time of 53 years.

If you're interested in the impact of carbon emissions, you obviously must not ignore the accelerating removal of CO2 from the atmosphere by natural carbon sinks! But that's exactly what the IPCC does to justify the "Net Zero" campaign.

In fact, AR6 explicitly posits that the removal of CO2 from the air by natural processes does not matter, because, they say, the effect of CO2 on temperature is determined by total emissions to date ("cumulative emissions"), which means it is unaffected by natural removals of CO2 from the air. (Note that "cumulative CO2 emissions" is not the amount of CO2 accumulated (remaining) in the atmosphere. It is defined to be the arithmetic summation of all anthropogenic CO2 emissions to date; refs: AR6 Glossary and NetZeroClimate.org.)

That's so obviously wrong that it sounds like a joke, doesn't it? But I'm not kidding.

They call it "transient climate response to cumulative CO2 emissions" (TCRE) and "remaining carbon budget" (RCB), and it is an essential assumption to justify the Net Zero campaign:

"The transient climate response to cumulative CO2 emissions (TCRE) is a metric of climate change that directly relates the primary cause of climate change (cumulative CO2 emissions) to global mean temperature change." (MacDougall 2016)

Here's the AR6 version (from AR6 WG1 TS.3.2.1; see also §5.5, §1.6.3, and SYN 3.3.1):

https://sealevel.info/AR6_WG1_TS3.2.1_TCRE_definition3.png

Notice their "high confidence" that CO2 has just as much warming effect after it's been removed from the atmosphere by natural sinks as it had while it remained, which is obviously impossible.

The higher the CO2 level in the atmosphere goes, the faster nature removes CO2 from the atmosphere. Quantitatively, for each 50 ppmv rise in the CO2 concentration, the rate of natural CO2 removals accelerates by about 1 ppmv/year. That makes the effective lifetime of CO2 added to the air (the "adjustment time") about 50 years, and the half-life of added CO2 50 × ln(2) ≌ 35 years.

That inconvenient fact was mentioned in the IPCC SAR (1995), but it has been omitted from subsequent IPCC Reports. The SAR (WGI TS, B.1, p.16) said:

"Within 30 years about 40-60% of the CO2 currently released to the atmosphere is removed."

That implies a half-life of 23 to 41 years, and an adjustment time of 1/ln(2) times that, which is 33 to 59 years.

Roughly the same result has also been reported by many other researchers, including:

In the real world, CO2 removed from the atmosphere no longer has a warming effect. But TCRE / RCB ignores the removal of CO2, and considers only additions of CO2 to the air. In other words, it is predicated on the assumption that the mere memory of CO2 once in the atmosphere has just as much warming effect as the CO2 which remains.

That assumption is essential to justify the Net Zero campaign—and it's nonsensical as orgone energy and quantum healing crystals. It is basically homeopathic climatology.

Homeopathic medicine is based on "water memory," the claim that even after a medicine is diluted so much that not a single molecule of the original therapeutic agent remains, its medicinal effect is undiminished, or even increased.

Similarly, homeopathic climatology is based on "CO2 memory," the assumption that CO2 has just as much warming effect after it is removed as it had while still in the air.

How can anyone take seriously an institution like the IPCC which promotes such crackpottery?

Here are some homeopathic climatology (TCRE / "cumulative carbon emissions" and RCB / "remaining carbon budget") papers:

  1. Allen, M., Frame, D., Huntingford, C. et al. (2009). "Warming caused by cumulative carbon emissions towards the trillionth tonne." Nature 458, 1163–1166. https://doi.org/10.1038/nature08019
  2. Matthews, H.D., Gillett, N., Stott, P. et al. (2009). "The proportionality of global warming to cumulative carbon emissions." Nature 459, 829–832. https://doi.org/10.1038/nature08047
  3. Gillett, N., Arora, V., Matthews, D. and Allen, M. (2013). "Constraining the Ratio of Global Warming to Cumulative CO2 Emissions Using CMIP5 Simulations." J Climate 26(18), 6844–6858. https://doi.org/10.1175/JCLI-D-12-00476.1
  4. Andrew H. MacDougall and Pierre Friedlingstein (2015). "The Origin and Limits of the Near Proportionality between Climate Warming and Cumulative CO2 Emissions." J Climate 28(10), 4217–4230. https://doi.org/10.1175/JCLI-D-14-00036.1
  5. MacDougall, Andrew H. (2016). "The Transient Response to Cumulative CO2 Emissions: a Review." Curr Clim Change Rep 2, 39–47 https://doi.org/10.1007/s40641-015-0030-6
  6. MacDougall, Andrew H. (2017). "The Uncertainty in the Transient Climate Response to Cumulative CO2 Emissions Arising from the Uncertainty in Physical Climate Parameters." J Climate 39(2), 813–827. https://doi.org/10.1175/JCLI-D-16-0205.1
  7. Matthews, H.D. et al. (2018). "Focus on cumulative emissions, global carbon budgets and the implications for climate mitigation targets." Environ. Res. Lett. 13(1) 010201. https://doi.org/10.1088/1748-9326/aa98c9
  8. Rogelj, J., Forster, P.M., Kriegler, E. et al. (2019). "Estimating and tracking the remaining carbon budget for stringent climate targets." Nature 571, 335–342. https://doi.org/10.1038/s41586-019-1368-z
  9. Lahn, G. (2020). "A history of the global carbon budget." WIREs Clim Change 2020; 11:e636. https://doi.org/10.1002/wcc.636
  10. Jenkins, S., Cain, M., Friedlingstein, P. et al. (2021). "Quantifying non-CO2 contributions to remaining carbon budgets." npj Clim Atmos Sci 4, 47. https://doi.org/10.1038/s41612-021-00203-9
  11. Matthews, H.D., Tokarska, K.B., Rogelj, J. et al. (2021). "An integrated approach to quantifying uncertainties in the remaining carbon budget." Commun Earth Environ 2, 7. https://doi.org/10.1038/s43247-020-00064-9
  12. Lamboll, R.D., Nicholls, Z.R.J., Smith, C.J. et al. (2023). "Assessing the size and uncertainty of remaining carbon budgets." Nat. Clim. Chang. 13, 1360–1367. https://doi.org/10.1038/s41558-023-01848-5

I tried to get ChatGPT to find papers which reject TCRE / RCB, without much success:

https://chatgpt.com/share/693d6ec3-742c-8009-a62a-842df99864f9

My guess is that some authors have probably tried to publish such papers, but activist "gatekeepers" at the major journals have rejected them. But that's just a guess.

Dave Burton
M: +1 919-244-3316
www.sealevel.info

 

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