One of the longstanding issues in mainstream climate “science” is the supposed notion that higher levels of CO2 cause higher temperatures. Long-term proxy markers of temperature and CO2 measurements appear to show that at least from a timing perspective, temperature changes lead CO2 changes. This would make sense as warmer temperatures lead to more vegetation and more carbon outgassing from the oceans, among other changes. And a colder world leads to the opposite. A new study suggests that this is exactly the case, that the increase in CO2 in our atmosphere is due to natural processes, not fossil fuel use. (RG Study)
As is usually the case, the study is technical, but what it shows is that about 95% of the CO2 that ends up in the atmosphere comes from ocean and soil degassing. The rates of those processes are correlated with temperature. Temperature varies naturally, on short and long time scales, due to solar and orbital changes, influenced by feedback mechanisms on earth, like clouds. My skepticism about the climate hysteria was born out of my experience as a child, now long ago, when all the science publications were warning about an impending ice age (best estimates now are it is around 3000 years away). It is no exaggeration to say that climate hysteria is an industry, driven to provide economic benefits to a few rich people involved in the renewable energy scam and to academic researchers. I am astounded that good research like this manages to sneak through the blockade erected by the climate industry.
It looks to be an interesting study. the ratio of 13C and 12C isotopes of carbon in CO2 is supposedly how to tell what in natural and what is fossil fuel generated co2. Most of the alarmist are claiming the the ratio is much higher evidence of fossil fuel CO2 based on climate studies. However I have not read those studies. I would like to see and contrast those studies and this study.
“This would make sense as warmer temperatures lead to more vegetation and more carbon outgassing from the oceans, among other changes.”
Those effects are in opposite directions since more vegetation would mean less CO2 in the atmosphere. The temperature dependence of CO2 solubility is well understood and is much too small to produce the observed CO2 changes, either recently or in the geologic record. Low CO2 during the ice ages is due to reduced overturning circulation in the oceans resulting in more CO2 sequestered in the deep ocean.
“As is usually the case, the study is technical, but what it shows is that about 95% of the CO2 that ends up in the atmosphere comes from ocean and soil degassing.”
But that has almost no effect on atmospheric CO2 since, in the absence of fossil fuel burning, the release from soil and oceans is balanced by organic matter deposition in the soil and CO2 dissolving in the ocean. Consider the stock market. A stock might have a high turnover ratio, but that does not have any effect on the amount of stock on the market. The latter can only be altered by new issues or buybacks.
I don’t think it is accurate that in a warmer climate the carbon cycle is completely balanced and does not add to atmospheric CO2. Among other things, how would you explain the extreme variations in CO2 levels for millions of years long before humans ever started burning fossil fuels. And I think, as this study describes, the reality is that more vegation results in more carbon pulled out of various sources, but also more carbon, particularly in the form of vegetative decay, being released, particularly in the form of CO2. That pretty obviously is the case when you look at the historical record.
On very long time scales (many millions of years) CO2 is affected by geological processes such as volcanoes and the weathering of rocks. On ice age time scales, variations are due to changes in ocean currents. Carbon in both the atmosphere and biosphere decreases while carbon in the deep ocean increases.
There is a constant “rain” of dead organic matter from the near-surface ocean into the deep ocean. That is the basis of most of the deep ocean food chain and results in the accumulation of carbon and other nutrients, like iron and phosphorus, in the deep ocean. Those are very slowly returned to the surface by the overturning circulation. The high concentration of nutrients in deep ocean water is why there is high productivity in areas of upwelling. A slowdown of the overturning circulation results in a greater accumulation of carbon in the deep ocean and less CO2 in the atmosphere.
thank you for the obviously informed comments, but you are continuing to oversimplify the total set of processes that determine CO2 levels in the atmosphere and overlooking the obvious fact that there was enormous variation in these levels far before human fossil-fuel use began. I would not say that human activities of all types, most importantly land use changes, don’t affect CO2 levels, but I would strongly disagree that fossil fuel use is the most important of those activities or that CO2 is the climate “control knob”. I tend to strongly distrust research coming from the climate hysteria crowd and be more trusting in anything to the contrary that manages to sneak through the peer review/journal cartel.