The Carbon Cycle Simply Explained Patrick Moore Co-Founder of Greenpeace Board of Directors for CO2 Coalition January 23, 2021 The root cause of the confusion about human vs “natural” CO2 (carbon dioxide) is that most scientists don’t seem to know the difference between a cash-flow statement and a balance sheet. The cash flow statement is about change of multiple factors over a specified period of time while a balance sheet is a snapshot in time. Flows vs. Stocks. In biology cash flow can be replaced by flows of carbon from one sink to another. And the biological balance sheet states how much carbon is present in each sink at a given point in time. Multiple annual balance sheets begin to show trends. The annual to decadal cycles of carbon occur between the atmosphere, the oceans and life within them, and land with all its life and carbon-rich soils. The deep ocean is on a longer cycle, perhaps 800 years in some cases. And then there is the carbon that could be called the trapped carbon that has been buried as fossil fuels or turned into carbonbased rocks like limestone. The terrestrial plants cycle more the 10 times as much carbon on an annual cycle as all human emissions. In spring and summer as plants grow they pull down about 120 Gt C (Gigatonnes Carbon), and in the fall and winter they emit it all back as they decay. Due to our emissions more C is now being taken down in spring than is being emitted in the fall making it something like 125Gt C down and 120 GtC back up. This is the greening of the Earth also called the CO2 fertilization effect. Human annual emissions are now about 10Gt C. The plant absorption and emission of C does not add any new C into the cycle. Humans emissions from fossil fuels and cement production are all a net increase of C in the cycle, as it was previously trapped (sequestered) for millions of years. One of the most important things to note is that all our emissions are putting CO2 back into the atmosphere and oceans that was removed from them by life’s processes in the first place and it has been a one-way process of continuing sequestration for many 1
millions of years. We come along and begin to restore a balance to the global carbon cycle by reversing a 150-million-year downward trend. That is why my motto is Celebrate CO2!
The world is beautiful and getting more beautiful, better able to support humanity with the help of carbon dioxide released by the use of fossil fuels. 2