Record-setting heat waves scorched the United States and other countries this spring and summer as planet-warming greenhouse gas emissions reached new highs and scientists at the United Nations warned that critical climate change goals are fast slipping out of reach. It is almost certain, they say, that global temperatures will at least temporarily rise more than 1.5 degrees Celsius over pre-industrial levels, threatening to destroy virtually all of the world’s coral reefs and making many regions uninhabitable. But they and other experts also note important successes around the world in replacing fossil fuels — which emit greenhouse gases when burned — with renewable energy such as solar and wind power. In the United States, President Biden on July 28 claimed a major potential legislative victory in his ambitious bid to reduce carbon emissions, but a June 30 Supreme Court ruling sharply limited the administration’s ability to regulate such emissions. Biden also has struggled to balance climate priorities with the need to lower gasoline prices and help Europe deal with fuel shortages related to Russia’s war in Ukraine.