Former head of NASA’s climate group issues dire warning on warming

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During the past year, the needles on the climate dashboard for global ice melt, heatwaves, ocean temperatures, coral die-offs, floods, and droughts all tilted far into the red warning zone. In summer and fall, monthly global temperature anomalies spiked beyond most projections, helping to drive those extremes, and they may not level off any time soon, said James Hansen, lead author of a study published Thursday in the journal Oxford Open Climate Change that projects a big jump in the rate of warming in the next few decades.

But the research was controversial even before it was published, and it may widen the rifts in the climate science community and in the broader public conversation about the severity and imminence of climate impacts, with Hansen criticizing the United Nations Intergovernmental Panel on Climate Change for underestimating future warming, while other researchers, including IPCC authors, lambasted the new study.

The research suggests that an ongoing reduction of sulfuric air pollution particles called aerosols could send the global average annual temperature soaring beyond the targets of the Paris climate agreement much sooner than expected, which would sharply increase the challenges faced by countries working to limit harmful climate change under international agreements on an already treacherous geopolitical stage.