If emissions of greenhouse gases were stopped, would the climate return to the conditions of 200 years ago?
No. Even if emissions of greenhouse gases were to suddenly stop, Earth’s surface temperature would require thousands of years to cool and return to the level in the pre-industrial era.
If emissions of greenhouse gases stopped altogether, global surface temperature would stop increasing but it would not significantly decline on human time scales. It would take many thousands of years for atmospheric CO2 to return to “pre-industrial” levels due to its very slow transfer to the deep ocean and ultimate burial in ocean sediments. Surface temperatures would stay elevated for at least a thousand years, implying a long-term commitment to a warmer than pre-industrial planet due to past emissions. Sea level would likely continue to rise for many centuries even after temperature stopped increasing [Figure 9]. Significant cooling would be required to reverse melting of glaciers and the Greenland ice sheet, which formed during past cold climates. The current CO2-induced warming of Earth is therefore essentially irreversible on human timescales. The amount and rate of further warming will depend almost entirely on how much more CO2 humankind emits.
Scenarios of future climate change increasingly assume the use of technologies that can remove greenhouse gases from the atmosphere. In such “negative emissions” scenarios, it assumed that at some point in the future, widespread effort will be undertaken that utilizes such technologies to remove CO2 from the atmosphere and lower its atmospheric concentration, thereby starting to reverse CO2-driven warming on longer timescales. Deployment of such technologies at scale would require large decreases in their costs. Even if such technological fixes were practical, substantial reductions in CO2 emissions would still be essential. .
Figure 9. Stylised schematic of how atmospheric carbon dioxide (CO2) concentrations, ocean heat uptake, and global surface temperature can evolve under net zero CO2 emissions. Process timescales are illustrative.
Page last updated: July 2026
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