A scenario where global temperatures temporarily exceed the 1.5 °C Paris Agreement target before eventually (hopefully) falling back. Researchers warn that it’s not just how high temperatures go, but how long they stay elevated because prolonged overshoot could trigger cascading risks in food, health, migration, and ecosystems. Some of these impacts may be irreversible, and overshoot could push sensitive systems past tipping points (e.g., ice sheets, rainfall patterns). Vulnerable regions, already warming faster, could face overlapping climate crises that outpace their ability to adapt, and adaptation measures like flood defenses or early-warning systems might come too late.

Finally, reliance on large-scale carbon removal (“negative emissions”) to pull temperatures down introduces huge uncertainties and potential social and environmental trade-offs, so decision-makers need to plan for overshoot proactively rather than assume it’s a temporary “pause” on the path to safety.

Source: Earth.Com