[HIGHLIGHTS] Have the oceans warmed earlier and faster than we imagined?

Small century-old sponges collected in the Caribbean Sea seem to indicate that the warming of surface waters started in 1860. The temperature of the ocean would have increased, on average, by + 1.7°C in 2020 compared to the start of the industrial era.

This is around 0.5°C more than what was estimated in the latest IPCC (Intergovernmental Panel on Climate Change) reports. The IPCC currently uses the years 1850 to 1900 as a reference period, which would lead to underestimating the extent of warming.