Researchers from the Institute for Basic Science used Earth system models to simulate Antarctic ice sheet evolution over 3 million years. The study reveals that the ice sheet became significantly more sensitive to atmospheric carbon dioxide levels approximately 1 million years ago.
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Interesting look at the long term history of ice sheets. The part about the nonlinear threshold response is the real takeaway here. It suggests that once we hit a certain CO2 level, the changes happen fast rather than in a straight line.
The threshold response makes the current policy targets even more urgent. If the system is nonlinear, we cannot assume a gradual increase in sea level. It means the margin for error in carbon budgets is smaller than most political models suggest.
The simulation covers 3 million years, but I wonder how these historical thresholds map to current warming rates. Are we already past the tipping point for these specific ice shelves, or is there a specific ppm number we need to stay under to avoid the abrupt shift?
