The Importance of 1.5°C for Global Economies due to Cryosphere and Other Impacts

Environmental Research Letters, 2 May 2023

This study summarizes the long-term risks and consequences associated with overshooting the 1.5°C limit of the Paris Agreement, focusing on the global impacts of rising temperatures on ice sheets, permafrost, wildfires, heatwaves, ocean acidification and more. One of their key findings: even temporarily exceeding 1.5°C will result in 10% higher global sea level rise by 2100, and this would continue increasing for centuries. Only the very low emissions scenario avoids a multi-century acceleration of sea-level rise from the Antarctic and Greenland ice sheets. Even seemingly small changes to sea level rise can make a substantial difference, especially in terms of economic damage to infrastructure in vulnerable coastal and low-lying regions.

The study also makes clear that the impacts of overshoot are not equal in geographic, economic or intergenerational terms. Heatwave exposure is already higher in lower-middle income countries than in high-income countries. In addition, researchers found that today’s newborns will experience up to 25% more heatwaves across their lifetime if temperatures overshoot by 0.35°C before returning to 1.5°C; this is more than six times higher than the amount of heatwaves experienced by those who are aged 60 today. The study underscores that these far-reaching impacts of cryosphere loss will have cascading effects on health, infrastructure, agriculture, education and a wide range of other socioeconomic variables; the best way to reduce these impacts is to urgently reduce emissions and avoid overshoot.

https://iopscience.iop.org/article/10.1088/1748-9326/accd83