April 14, 2016

2015 was on average the warmest year globally since record keeping began nearly 150 years ago–and the 2016 average is shaping up to be even hotter. A strong El Niño deserves the brunt of the blame. The unusually warm Pacific Ocean surface waters that mark an El Niño event amplify heat over land. Temperatures spiked around the globe as El Niño began last fall, leading to month after month of record-breaking heat. Global temperatures this past February were 2.2°F above the 20th century average, making it the most anomalously hot month on record. But man-made global warming is still playing a lasting role in the record heat. “That’s how we will see the effects of climate change: the extremes will become more extreme,” says Michael Mann, a climate scientist at Penn State University.

[The following text appears within a chart. Please see hardcopy or PDF for actual chart.]

Difference from average, in degrees Celsius

El Niño exacerbated global warming last year

1.0

0.8

0.6

0.4

0.2

0

-0.2

-0.4

1880

1900

1920

1940

1960

1980

2000

2015

NOAA; U.N.

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This appears in the April 25, 2016 issue of TIME.

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