The latest report from the Intergovernmental Panel on Climate Change made it clear that averting the worst consequences of climate changes (lesser consequences are by now all around us) will mean quickly cutting back on the use of fossil fuels that cause global warming.

Big Oil didn’t get the memo.

Faced with what they saw as an existential threat to their businesses, BP, Valero, Phillips 66, the Koch brothers and other members of the fossil fuel fraternity dumped more than $30 million into Washington State to crush a ballot initiative that would have imposed the first taxes in the nation on carbon emissions. Backers of the proposal hoped it would serve as a template for similar action elsewhere and perhaps for the country as a whole. But the theoretical elegance of a carbon tax, which most economists and scientists believe is the surest way to control emissions on a broad scale, was no match even in reliably Democratic Washington for relentless fearmongering about job losses, higher electricity bills and more expensive gasoline.

The defeat in Washington was the most disappointing setback for climate activists in the midterm elections on Tuesday, a day of decidedly mixed messages on climate change in particular and environmental issues more broadly.

On the negative side of the ledger, the firewall in the Republican-majority Senate against any action at all on climate was fortified by assured Republican pickups in North Dakota, Indiana and Missouri. One new senator, Representative Kevin Cramer, who defeated Heidi Heitkamp in North Dakota, served as an energy adviser in the 2016 Trump campaign and was an architect of the president’s energy agenda, which consists mainly of drilling oil and gas wells on just about every square inch of available federal land, onshore and off. If Rick Scott, the Republican Florida governor, maintains his narrow lead over Senator Bill Nelson, a Democrat, it will be another major loss for the environment. Governor Scott’s administration for a time barred the use of the term “climate change” in official documents, and the governor was so inattentive to Florida’s many climate-related risks, including sea level rise and flooding, that he was sued by a group of young people for ignoring the issue.