February Global Mean Temperature Update

The UAH lower troposphere satellite data reveals that February 2024 anomaly was 0.93C, equal to the record set in October 2023. The uptick from last month is probably due to El Nino but the 2023/24 spike in temperature as a whole is starting to look rather different from previous El Nino spikes. It now encompasses September through to the end of February - a full 6 months. This is unlike any other previous El Nino spike in the record.

As I said back in September:

The current El Nino has only just got going and ensemble forecasts predict that it will be a moderate event at best, so it’s not currently El Nino which is keeping global temperatures high and as we note, El Nino causes temperatures to spike, briefly, usually during late winter/spring, soon after mid tropical Pacific ocean temperatures reach their peak around Christmas (hence El Nino = ‘the boy child’).

So will the current ‘global simmering’ continue throughout the year or will temperatures drop sharply in the next few months and then perhaps peak again early next year due to El Nino? Who knows. If global simmering continues though, then something quite extraordinary will be causing it - and that’s not man-made greenhouse gases. The obvious culprit would have to be the Hunga Tonga eruption which caused a huge amount of water vapour (a powerful greenhouse gas) to enter the stratosphere, much of which is presumably still there.

Global temperature has varied little during its peak over the last 6 months and now it is back to where it was in October. If the peak is entirely due to El Nino (even a ‘weird’ El Nino), we should expect to see global temperature drop sharply very soon, just as it did with other El Ninos. But what we have so far is half a year of ‘global simmering,’ which is unprecedented in the satellite record.

What is even more fascinating is that some models are now predicting a ‘super La Nina’ for the second half of 2024 which would wind back central Pacific temperatures to values not seen since the 1980s! We might then reasonably expect 2025 to be a very cold year by the standards of the early 2020s - if any heating due to Hunga Tonga has fizzled out by then. It looks like it’s going to be a very interesting year or two on Laboratory Earth.