So why isn't that the El Niño record?

Transcript

1. A patch of the Pacific bigger than the whole European Union
2. just had its most unusually warm week since US weekly records began in 1981.
3. But measured the way American forecasters now measure El Niño,
4. it hasn't broken the record.
5. Not yet.
6. The patch sits on the equator, south of Hawaii.
7. Normally, trade winds push warm surface water west, toward Asia.
8. Every few years they weaken, and the warm water flows back east.
9. That's El Niño, and it can change the weather around the world.
10. NOAA, the US weather agency, checks this patch every week.
11. In the week to 3 October, it was 3.2 °C above normal for the time of year.
12. The highest week before that was in November 2015, at 3 °C.
13. So why isn't that the El Niño record?
14. There are two reasons.
15. First, El Niño is officially measured over three months, not one week.
16. Second, the rest of the tropical ocean is warmer than normal too.
17. So NOAA, and Australia's weather bureau, now measure El Niño against its surroundings:
18. how much more this patch has warmed than the tropics around it.
19. On the plain three-month reading,
20. the strongest El Niño since 1950 was 2015 to 2016.
21. On NOAA's El Niño measure, it's the winter of 1982 to 1983, at 2.4 °C.
22. From July to September, this one reached 1.7.
23. That record may not last the year.
24. NOAA puts the chance that the October-to-December average
25. beats it at 83%.
26. What does a strong El Niño do?
27. The climate scientist Zeke Hausfather
28. went back through the 8 strong ones since 1957,
29. as the plain reading counts them.
30. Indonesia was drier than normal in all 8.
31. America's Gulf Coast had a wetter winter in all 8.
32. Southern Africa, where tens of millions of people depend on maize, was drier in 6.
33. For most of Europe, he says, this winter could go either way.
34. Global temperature follows El Niño by a few months.
35. In a September post,
36. his forecast put the chance that 2027 is the warmest year ever measured at about 95%.
37. So one record has already fallen: the weekly reading.
38. El Niño's own record, the three-month one, will probably fall too.
39. Part of this heat is the ocean around the patch,
40. which has been warming for decades.
41. Exactly how much, neither number can tell you.