I’m a Climate Scientist. I’m Not Screaming Into the Void Anymore.

Dr. Marvel, a climate scientist at the environmental nonprofit Project Drawdown, was a lead author on the Fifth National Climate Assessment. Two and a half years ago, when I was asked to help write I hesitated. Did we need another warning of the dire consequences of climate change in this country? The answer, legally, was yes: Congress mandates that the National Climate Assessment be updated every four years or so. But after four previous assessments and six United Nations reports since 1990, I was skeptical that what we needed to address climate change was yet another report. In the end, I said yes, but reluctantly. Frankly, I was sick of admonishing people about how bad things could get. Scientists have raised the alarm over and over again, and still the temperature rises. like heat waves, floods and droughts are becoming more severe and frequent, exactly . We were proved right. It didnt seem to matter. Our report, which was released on Tuesday, contains more dire warnings. There are plenty of new reasons for despair. Thanks to recent scientific advances, we can now to specific extreme weather disasters, and we have a better understanding of how in the climate system can make warming even worse. We can also now more confidently forecast catastrophic outcomes if global emissions continue on their current trajectory. But to me, the most surprising new finding in the Fifth National Climate Assessment is this: There has been genuine progress, too. Im used to mind-boggling numbers, and there are many of them in this report. Human beings have put about of carbon in the atmosphere since the Industrial Revolution more than the weight of every living thing on Earth combined. But as we wrote the report, I learned other, even more mind-boggling numbers. In the last decade, the cost of wind energy has declined by 70 percent and solar has declined 90 percent. Renewables now make up 80 percent of new electricity generation capacity. Our countrys greenhouse gas emissions are falling, even as our G.D.P. and population grow. In the report, we were tasked with projecting future climate change. We showed what the United States would if the world warms by 2 degrees Celsius. It wasnt a pretty picture: more heat waves, more uncomfortably hot nights, more downpours, more droughts. If greenhouse emissions continue to rise, we could reach that point in the next couple of decades. If they fall a little, maybe we can stave it off until the middle of the century. But our findings also offered a glimmer of hope: If emissions fall dramatically, as the report suggested they could, we may never reach 2 degrees Celsius at all For the first time in my career, I felt something strange: optimism. And that simple realization was enough to convince me that releasing yet another climate report was worthwhile. Something has changed in the United States, and not just the climate. State, local and tribal governments all around the country have begun to take action. Some politicians now actually campaign on climate change, instead of ignoring or lying about it. Congress passed federal climate legislation something Id long regarded as impossible in 2022 as we turned in the first draft. We are having trouble retrieving the article content. Please enable JavaScript in your browser settings. Thank you for your patience while we verify access. If you are in Reader mode please exit and your Times account, or for all of The Times. Thank you for your patience while we verify access. Already a subscriber? . Want all of The Times? .