How many hot days and heavy precipitation days will grandchildren experience that break the records set in their grandparents’ lives?

Abstract

One of the major barriers to climate communication is that climate change is often presented to the public in such a way that impacts seem distant in time. To improve how climate change resonates with people, we propose a simple indicator: how many extreme events (hot days and heavy precipitation days) are grandchildren projected to experience that their grandparents will not experience in their lives? We analyse the Coupled Model Intercomparison Project Phase 6 ensemble. During grandchildren's lifetime (2020–2100) under the shared socioeconomic pathway 5–8.5 (SSP5-8.5), in some tropical regions, they are projected to experience >1000 hot days and >5 heavy precipitation days breaking records set in their grandparents' lifetime until 2040. These numbers of unprecedented hot days and heavy precipitation days under SSP5-8.5 are greater in countries with lower CO₂ emissions and income per capita than in countries with higher CO₂ emissions and income per capita. We show that not only the numbers of unprecedented hot days and heavy precipitation days but also their unevenness across countries can be significantly lowered in the SSP1-2.6 scenario, which is consistent with the 2 °C goal of the Paris Agreement. This new approach would help adults easily understand how their climate change mitigation efforts could decrease the unprecedented extreme events during youths' lifetime and reduce the intergenerational and intragenerational inequalities regarding extreme events.