Ongoing AMOC and related sea-level and temperature changes after achieving the Paris targets

Résumé

While the Atlantic Meridional Overturning Circulation (AMOC) is expected to weaken under increasing GHGs, it is unclear how it would respond to stabilization of global warming of 1.5 or 2.0 °C, the Paris Agreement temperature targets, or 3.0 °C, the expected warming by 2100 under current emission reduction policies. On the basis of stabilized warming simulations with two Earth System Models, we find that, after temperature stabilization, the AMOC declines for 5–10 years followed by a 150-year recovery to a level that is approximately independent of the considered stabilization scenario. The AMOC recovery has important implications for North Atlantic steric sea-level rise, which by 2600 is simulated to be 25–31% less than the global mean, and for North Atlantic surface temperatures, which continue to increase despite global mean surface temperature stabilization. These results show that substantial ongoing climate trends are likely to occur after global mean temperature has stabilized.