Michal Kurtyka, the Polish official who led U.N. climate change negotiations in Katowice, Poland. On Dec. 15., nearly 200 countries agreed to a set of rules that will implement the landmark Paris agreement.
Every summer, downy mildew spreads from Florida northward, adapting to nearly every defense pickle growers have in their arsenals and destroying their crops.
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Scientist He Jiankui was criticized by colleagues after his claim to have created gene-edited babies became public. Three leading scientific organizations are calling for more controls.
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Sea ice is seen from NASA's Operation IceBridge research aircraft off the northwest coast of Greenland in March 2017. A new report says rapid warming over the past three decades has led to a 95 percent decline of the Arctic's oldest and thickest ice.
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Pittsburgh Mayor Bill Peduto at a city climate action event in San Francisco in September. Peduto is representing U.S. mayors at the United Nations climate meeting underway in Katowice, Poland, this week.
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Russian cosmonaut Oleg Kononenko performs a spacewalk outside the International Space Station on Tuesday. Kononenko and Sergey Prokopyev are inspecting a section where a mysterious leak appeared on Aug. 30.
NASA via AP