Knowledge Science

DURBAN, South Africa — Doctors and nurses at a South African hospital group noticed an odd spike in the number of Covid-19 patients in their wards in late October. The government had slackened its lockdown grip, and springtime had brought more parties. But the numbers were growing too quickly to easily explain, prompting a distressing question.

“Is this a different strain?” one hospital official asked in a group email in early November, raising the possibility that the virus had developed a dangerous mutation.

The National Climate Assessment, America’s premier contribution to climate knowledge, stands out for many reasons: Hundreds of scientists across the federal government and academia join forces to compile the best insights available on climate change. The results, released just twice a decade or so, shape years of government decisions.