Ocean temperatures have been off the charts since mid-March 2023, with the highest average levels in 40 years of satellite monitoring, and the impact is breaking through in disruptive ways around the world.

The sea of Japan is more than 7 degrees Fahrenheit (4 degrees Celsius) warmer than average. The Indian monsoon, closely tied to conditions in the warm Indian Ocean, has been well below its expected strength.

Spain, France, England and the whole Scandinavian Peninsula are also seeing rainfall far below normal, likely connected to an extraordinary marine heat wave in the eastern North Atlantic. Sea surface temperatures there have been 1.8 to 5 F (1 to 3 C) above average from the coast of Africa all the way to Iceland.

So, what’s going on?