Is the recent global warming a “termination shock”?

Quick Overview

The recent rapid global warming observed since the mid-20th century is primarily driven by increased greenhouse gases, not solely by the reduction of cooling aerosols, contrary to what some climate scientists suggest, as the 2024 Arctic Report Card confirms the tundra is now a net source of carbon dioxide, and the IPCC's assessment of aerosol forcing is likely an underestimate, leading to a potentially worse "Faustian bargain" where stopping pollution causes rapid warming.

Key Points: Recent, rapid global warming, particularly since 1970, is largely due to increased greenhouse gases, despite the cooling effect of aerosols (-0.5 to -2.5 W/m²), which reduces the net warming effect. The 2024 Arctic Report Card shows the Arctic tundra has become a net source of carbon dioxide and methane due to thawing permafrost and increased wildfires. A 2024 paper by Yuan et al. suggests that the International Maritime Organization's (IMO) shipping emission rules, intended to reduce pollution, might trigger a severe 'termination shock' causing substantial radiative warming if shipping emissions are abruptly cut. Climate scientists James Hansen and co-authors argue that the IPCC's estimate of aerosol climate forcing (-1.6 ± 0.3 W/m²) is an underestimate, implying the 'Faustian bargain' (benefiting from cooling aerosols while emitting warming CO2) is worse than expected. If aerosol reduction leads to a temperature increase of less than 0.05°C regionally, it is small compared to the warming caused by continued CO2 emissions, suggesting the focus should remain on reducing CO2, not relying on aerosol cooling. Planet Wild, a nature protection organization, is funding projects to restore nature in the Amazon, including forest patrols and legal work to secure UNESCO World Heritage status for the Xingu region. The video strongly implies that relying on geoengineering concepts like atmospheric injection (represented by a spray can) or abrupt pollution cuts (termination shock) is dangerous compared to tackling the root cause of long-term CO2 emissions.