For quite some time we have known that atmospheric CO2 lags Earthly temperature in both directions. This fact has been repeatedly and internationally validated at both ends of the Earth. It is, frankly and simply, a known fact. But here is the rub. Very few ever speak to why this would be so obviously true. Is it not painfully obvious? How big does the picture have to be and how many brilliant colors does it need to be painted with before it becomes widely recognized?
Here are the primary sources of natural CO2 release in decreasing order of quantity of carbon emitted: oceanic release, microbial decay, insect activity, frozen terrestrial release; volcanic release; forest fire and then mammalia exhalations and emissions – summing to a total of ~325-485 petagrams. Then there is our ~2.0% anthropogenic release at ~8-9 petagrams. (Based on terrestrial sources alone, without oceans, anthropogenic release is ~3-4% of the natural flux. Some argue that the oceans are net absorbers and ignore the oceanic release estimate below. However, according to the argument presented herein the oceans are net emitters as indicated below when warmed by ~0.5oC per century).
Notes: Interglacial estimates come from my notes of IPCC, NASA and NOAA web-sites of 2005 and 2006, when these sites carried detailed analysis of natural CO2 emission sources. Terrestrial estimates of CO2 emission place the anthropogenic contribution at ~3-4%. The annual oceanic release estimate above is modeled (from laboratory experiment by NOAA) and would arise only if and when the oceans begin to follow a 0.5oC per century temperature rise profile (as they most likely have been). Thermal modulations to all non-human emission can be expected to be quite large (up to 2X and more at the extremes of global temp). The only value that can be estimated with high accuracy is the anthropogenic contribution which is far less than both the uncertainty and, most importantly, the variability of many of the natural emission sources.
We don’t know for sure that the oceans are net-absorbers or net-emitters at this time. Just as we don’t know for sure that the oceans are net-cooling or net-warming at this time. However, I have to say that it appears entirely plausible, and in evidence, that the oceans have recently been net-emitters (and largely, almost entirely, accountable for the current spike in atmospheric CO2). The Earth has been warming for ~150 years since the Little Ice Age (actually ~400 years since the coldest depths of the Little Ice Age). Regardless of their enormous thermal mass, the oceans have to respond to this thermal trend at some point (historically they respond vigorously at our current level of <800y least-count detection). And if they are warmed, the oceans will surely dump a component of their vast dissolved CO2 into the atmosphere (as they most likely have been).
Many will rightfully argue with the exact magnitudes of various emission sources in the table. But the ordering of the table is in little doubt. Microbial and insect emissions are by far the #1 and #2 CO2 emitting life forms on Earth (by ~10x each). We humans are a distant 4th – somewhat less than, but on par with, non-human mammalia. And the fact that all these Natural sources would be stimulated by increased Earthly temperature is in little doubt.
Now I ask you: Is it not clear that the Earth has warmed over the last 400 years since the coldest depth of the Little Ice Age? Is it not similarly clear that we should expect atmospheric CO2 to rise given 400 years of this thermal stimulation?
When we examine the seasonal variation in atmospheric CO2 we see an indisputable clockwork signature. Some ask about this variation: What processes start net CO2 production in September and end net production in May? – As this is how the seasonal variation seemingly goes.
But a much better way to ask the same question is: What CO2 sequestering process slows beginning in September and doesn’t recover till May?
And the answer would be photosynthetic sequestering of the majority Earthly vegetation in the Northern Hemisphere.
How can it be made clearer that CO2 is currently rising and varying for natural cause?
Lastly, let me make an obvious prediction predicated on the prediction that the Earth has recently begun to cool and assuming that some appreciable level of cooling (0.1-0.3 degree C) takes place over the next several years.
Atmospheric CO2 is going to spike hard in the coming years. And before it stops spiking it will likely attain an annual contribution level appreciably larger than the then-current anthropogenic emission.
Why? Mauna Loa makes clear that majority CO2 sinks respond significantly to a temperature drop with a short lag-time measured in only months or even weeks. Natural CO2 sources, however, respond much more slowly to the same thermal perturbation (the oceans in particular).
For more detail on these issues (along with an intriguing possibility to “save the planet”, see: https://www.dropbox.com/s/ygv83mwpytn4p65/AN%20ENGINEER%E2%80%99S%20TAKE%20ON%20MAJOR%20CLIMATE%20CHANGE%20F.53.pdf
About the Author
Ronald D Voisin is a retired engineer. He spent 27 years in the Semiconductor Lithography Equipment industry mostly in California’s Silicon Valley. Since retiring in 2007, he has made a hobby of studying climate change. Ron received a BSEE degree from the Univ. of Michigan – Ann Arbor in 1978 and has held various management positions at both established semiconductor equipment companies and start-ups he helped initiate. Ron has authored/co-authored 55 patent applications, 24 of which have issued.