An Important Tipping Point for Our Total Earth System Has Passed – Natural Sequestration of Atmospheric CO2 Has Begun To Decline
Natural sequestration of carbon dioxide is in decline: climate change will accelerate
The familiar cover image of the Mauna Loa atmospheric CO2 concentration now reveals what has been coming for decades. Natural sequestration of CO2 by our Earth systems has begun to decline. This marks a tipping point of extreme importance. Not only does it tell us that our natural systems are degraded, and that this degradation cannot be stopped unless we restore our climate temperature back to within the evolutionary boundaries of our Earth systems so they can self restore, it tells us that climate change will now accelerate faster, even if human-caused emissions do not increase.
Forest degradation from insects and disease across the world, declining ocean and soils absorption and increased permafrost thaw have flipped Earth’s natural greenhouse gas sequestration systems into decline. What this means is that, if our Earth systems were sequestering greenhouse gases at the same rate they did in the 1960s, the annual atmospheric growth rate would have been 1.9 ppm CO2. Instead, the annual growth rate is 2.5 ppm CO2, and this is the 2010 to 2020 average. In 2023 and 2024, the atmospheric growth rate jumped markedly from previous data at about 3.5 ppm CO2 growth per year, according to the Mauna Loa CO2 records in Hawai’i (that have been threatened to be discontinued by the fascist dictator in chief.)
The image above literally shows the 2008 tipping point when our total Earth system flipped its increasing sequestration rate into decline. Human’s emissions will now need to decrease by 0.3% per year, simply to compensate for declining terrestrial sequestration observed to date. Of the 41.6 billion tons CO2 emitted from fossil fuels ag and forest abuses in 2024, half, or about 20.8 Gt were removed by Earth systems. This decline is quite meaningful already at 0.25 Gt per year and the increase will only increase further, and nonlinearly, as current feedbacks grow and new ones begin to emit. It is also very important to note that the decline will very likely be steeper than the increasing sequestration rate before the tipping point in 2008. This is because of feedbacks increasing in number as we warm farther away from the evolutionary boundary of our old climate at about 1 degree C warming above normal, and as increased warming almost always means nonlinearly faster and more extensive feedbacks.
Over 700 Gigatons of CO2 are at risk from the Amazon alone. Globally, tropical forests’ extents are three times the Amazon’s with about 2,200 gigatons of CO2 at risk. Of course not all of the carbon is at risk, but likely mor than half is, equalling to something very similar to all greenhouse gas emissions of humanity in all time.
(Abstract) The rate of natural sequestration of CO2 from the atmosphere by the terrestrial biosphere peaked in 2008. Atmospheric concentrations will rise more rapidly than previously, in proportion to annual CO2 emissions, as natural sequestration is now declining by 0.25% per year. The current atmospheric increment of +2.5ppm CO2 per year would have been +1.9ppm CO2, if the biosphere had maintained its 1960s growth rate. This effect will accelerate climate change and emphasizes the close connection between the climate and nature emergencies. Effort is urgently required to rebuild global biodiversity and to recover its ecosystem services, including natural sequestration.
Curran and Curran, Natural sequestration of carbon dioxide is in decline – climate change will accelerate, Royal Meteorological Society, March 2025.
https://rmets.onlinelibrary.wiley.com/doi/10.1002/wea.7668