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Abstract

Human activities are expected to delay the next glacial inception because of the long atmospheric lifetime of anthropogenic CO2. Here we present Earth system model simulations for the next 200,000 years with dynamic ice sheets and interactive atmospheric CO2, exploring how emissions will impact a future glacial inception. Historical emissions (500 PgC) are unlikely to delay inception, expected to occur under natural conditions around 50,000 years from now, while a doubling of current emissions (1000 PgC) would delay inception for another 50,000 years. Inception is generally expected within the next 200,000 years for emissions up to 5000 PgC. Our model results show that assumptions about the long-term balance of geological carbon sources and sinks has a strong impact on the timing of the next glacial inception, while millennial-scale variability in the Atlantic Meridional Overturning Circulation influences the exact timing. This work highlights the long-term impact of anthropogenic CO2 on climate.