Hundreds of scientists assembled this week by the United Nations rang the alarm bell as loudly as they ever have on climate change, detailing the intensifying fires, floods and other catastrophes that will continue to worsen until humans dramatically scale back greenhouse gas emissions.

U.N. Secretary-General António Guterres called the sobering, sprawling report from the Intergovernmental Panel on Climate Change a “code red for humanity.” But it remains unclear if the new findings alone would be enough to spur new action in a Washington as politically divided as ever.

Scientists made clear that the world must make immediate and dramatic cuts to the climate-warming emissions produced by the burning of fossil fuels and other human activities. But Tuesday provided the latest example of how climate action, at least on Capitol Hill, remains a fight over each dollar and each incremental policy.

Lawmakers are wrestling over a pair of major bills that include significant climate provisions — one with limited bipartisan support, the other being shepherded through Congress by slim Democratic majorities. Each, if passed, would invest billions of dollars in the sort of clean energy transition the United States must make to have any chance of hitting the goal set by President Biden to cut the nation’s emissions by at least 50 percent by the end of this decade.

Psychological research shows that climate change can alter an individual’s mental health both directly and indirectly, impacting how we respond to this crisis. (John Farrell/The Washington Post)

The evolution of the two bills provides a lesson in how the political climate in Washington makes it difficult to act with the urgency the science says is necessary.

Climate change remains a distinctly fraught issue in the United States compared with many other countries, with the de facto leader of one of the two major parties — former president Donald Trump — dismissing the scientific consensus about human-caused climate change and downplaying its risks throughout his term.