Living in Bomb Time — 41

A discussion of Hansen’s last few posts.

This graph was from his post of November 2023. At that point the 12 month Running Mean showed the Global Mean Temperature at +1.4°C. Hansen was projecting the peak of the El Nino at around +1.7C (pink dot). With temperatures cooling down slightly with La Nina conditions and the Rate of Warming shifting from the green line to the yellow cone.

This is his update in May of 2024.

Comments on Global Warming Acceleration, Sulfur Emissions, Observations — (16 May 2024) James Hansen, Pushker Kharecha, Makiko Sato

See the progression of the “blue line”. That's the 12 month “running mean” of the Global Mean Temperature. That's NOT the same as the current GMT. It’s the “mean” of temperatures for the last 12 months. In 2023 temperatures started rapidly climbing in March and didn't peak until September. This line is about to go shooting up and will then “fall back” a little bit around October this year.

“Global temperature (12-month mean) is still rising at 1.56°C relative to 1880–1920 in the GISS analysis through April (Fig. 1). [Robert Rohde reports that it is 1.65°C relative to 1850-1900 in the Berkeley Earth analysis.3] Global temperature is likely to continue to rise a bit for at least a month, peak this summer, and then decline as the El Nino fades toward La Nina.”

Takeaway:

12 Month Mean GMT:

GISS (Moderate/Minimizer Aligned Agency) says +1.56°C above an 1880–1920 average baseline.

Berkeley Earth (Moderate NGO) says +1.65°C above an 1850–1900 average baseline.

Who you listen to, can shave about a tenth of a degree over the amount of warming that gets reported. GISS is regarded as the “gold standard”. BTW- when the press says that we are at “+1.56°C of warming”. That’s whose number they are using.