by Two and a half years ago, when I was asked to help write the most authoritative report on climate change in the United States, I hesitated. Will we really Need another warning about 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 tackle climate change was yet another report.
In the end, I said yes, but reluctantly. Frankly, I was tired of warning people about how bad things could get. Scientists have sounded the alarm repeatedly and still the temperature rises. Extreme events like heatwaves, floods and droughts are becoming more severe and frequent, exactly as we predicted they would. We were proven right. It didn’t seem to matter.
Our report, released on Tuesday, contains more dire warnings. There are many new reasons for despair. Thanks to recent scientific advances, we can now link climate change to specific extreme weather catastrophes and have a better understanding of how feedback loops in the climate system can make warming even worse. We can also now more confidently predict catastrophic outcomes if global emissions continue on their current trajectory. But to me, the most surprising new finding from the Fifth National Climate Assessment is this: There has also been genuine progress.
I’m used to surprising numbers and there are a lot of them in this report. Humans have put around 1.6 billion tonnes of carbon into the atmosphere since the Industrial Revolution – more than the weight of all living things on Earth combined. But as we were writing the report, I became aware of other, even more surprising numbers. In the last decade, the cost of wind energy has decreased by 70% and solar energy has decreased by 90%. Renewable energy now represents 80% of new electricity production capacity. Our country’s greenhouse gas emissions are declining, at the same time as our GDP and population are growing.
In the report, we were tasked with projecting future climate change. We show what the United States would be like if the world warmed by 2 degrees Celsius. It wasn’t a pretty picture: more heat waves, more uncomfortably hot nights, more torrential rains, more droughts. If greenhouse gas emissions continue to rise, we could reach that point within the next few decades. If they drop a little, maybe we can avoid this until mid-century. But our findings also offered a glimmer of hope: If emissions drop sharply, as the report suggested they might, we may never reach 2 degrees Celsius.. For the first time in my career I felt something strange: optimism. And this simple observation was enough to convince me that it was worth publishing another climate report.
Something has changed in the United States, and not just the weather. State, local and tribal governments across the country began to act. Some politicians now campaign on climate change, rather than ignoring it or lying about it. Congress passed federal climate legislation – something it had long considered impossible – in 2022, when we presented the first draft.
And while the report emphasizes the urgency of limiting warming to avoid dire risks, it also brings a new message: We can do this. We now know how to make the drastic emissions cuts we would need to limit warming, and it is very possible to do so in a sustainable, healthy and fair way. The conversation progressed and the role of scientists changed. We are no longer just warning about danger. We are showing the way to safety.
I was wrong about the previous reports: they did It matters, after all. As climate scientists warned the world of catastrophe, a small army of scientists, engineers, policymakers and others got to work. These first responders helped us move toward our climate goals. Our warnings did their job.
To limit global warming, we need a lot more people on board. This will be difficult: it will require large-scale changes in infrastructure and behavior, as well as the removal of carbon from the atmosphere. And not everyone is on board yet. In particular, the fossil fuel industry still ignores science. Oil, gas and coal companies have already made plans for infrastructure that, if used as intended, would move the world past the Paris agreement’s 1.5 degrees Celsius target in the coming decades.
To avoid this, we need to reach those who have not yet been touched by our warnings. I’m not talking about the fossil fuel industry here; nor do I particularly care about winning over the small but vocal group of committed climate deniers. But I believe we can reach many people whose eyes glaze over when they hear another dire warning or see another report like the one we just published.
The reason is that we now have a better story to tell. The evidence is clear: responding to climate change will not only create a better world for our children and grandchildren, but it will also make the world better for us right now.
Eliminating sources of greenhouse gas emissions will make our air and water cleaner, our economy stronger, and our quality of life better. It could save hundreds of thousands or even millions of lives across the country through air quality benefits alone. Using land more wisely can limit climate change and protect biodiversity. Climate change hits hardest on communities that are victims of injustice in our society: low-income people, people of color, children and the elderly. And climate action can be an opportunity to repair legacies of racism, neglect and injustice.
I could still tell scary stories about a future ravaged by climate change, and they would be true, at least on the trajectory we’re currently on. But it is also true that we have a unique opportunity in the history of humanity, not only to prevent the worst effects, but to make the world better right now. It would be a shame to waste this opportunity. So I don’t want to just talk about the problems anymore. I want to talk about the solutions. Consider this your last warning from me.
Kate Marvel, a climate scientist at the environmental nonprofit Project Drawdown, was the lead author of the Fifth National Climate Assessment. Previously, she was a researcher at Columbia University and NASA’s Goddard Institute for Space Studies.
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