Subscribe now

Analysis and Environment

Do we finally understand what caused record heat in 2023 and 2024?

Scientists have struggled to explain why global temperatures have shot up in recent years, but ocean cloud cover has now emerged as a crucial piece of the puzzle

By Madeleine Cuff

12 March 2025

Clouds over the ocean are reflecting less sunlight than before, resulting in the planet absorbing more heat

David Pattyn/NATURE PICTURE LIBRARY/SCIENCE PHOTO LIBRARY

After months of frenetic research, scientists are edging closer to understanding why the planet has been so hot since 2023.

That year, the average sea surface temperature across the world hit a record high, smashing the previous figure by around 0.25°C. It remained at record-breaking levels well into 2024, driving overall global temperatures to new recorded highs.

The scale…

Sign up to our weekly newsletter

Receive a weekly dose of discovery in your inbox! We'll also keep you up to date with New Scientist events and special offers.

Sign up

To continue reading, subscribe today with our introductory offers

Piano Exit Overlay Banner Mobile Piano Exit Overlay Banner Desktop