In 2011, one of the worst blackouts in U.S. history left seven million people across the Southwest U.S. and into Mexico without power. The cities of San Diego and Tijuana were paralyzed for more than 12 hours, leading to sewer spills, water contamination, and a shutdown of the San Onofre nuclear plant. The blackout was determined to be exacerbated by extreme heat the region was experiencing at the time—something that the Southwest is going to be seeing much more of in the future.

Cities used to frame a situation like this blackout as a local emergency: Assess the impact, repair the damage. But in an age of climate change, this is an outdated way to think about risk. “What we’ve found is that protocol assumes that things are going to be back on track in a very short amount of time,” says Susanne Moser, a social science research fellow at the Woods Institute for the Environment at Stanford University. “Twenty to 40 years out, the heat wave will be worse. When the heat wave lasts an entire week, and the electricity is not coming back on for a whole week, all of a sudden plans for a blackout don’t work as well.”

The job of imagining this kind of nightmare scenario for cities has fallen to scientists like Moser and her colleague Juliette A. Finzi Hart, who study the far-reaching repercussions of climate change-related disasters. Moser and Hart’s emerging field of climate research explores what are called teleconnection patterns, looking at the “cascading effects” of these disasters on humans, from the short-term interruption of the movement of goods to the long-term impact on public health.

One of the best examples of teleconnections is the way human migration is being altered by climate change, says Hart, who is an oceanographer with the U.S. Geological Survey’s Pacific and Coastal Marine Science Center. She points to the way that an extreme weather event like Hurricane Katrina affected more cities than just New Orleans. “The city floods, and people go where they have some kind of connection. Certain cities got more Katrina refugees based on their relationships,” she says. “But on the other side you have to think about the chronic, slower-moving migration caused by sea level rise or extreme heat—this trickle effect of moving from one place to another that’s better suited to climate change.”

Planning for the “new normal” of climate change has become more common in cities, which are home to a majority of Americans and more likely to be located along vulnerable coasts or waterways. That’s why Moser and Hart are working with the city of Los Angeles—to help prepare the region for the inevitable mega-blackouts to come.

Cities have a new word for this type of planning: resilience. And it’s becoming a big part of the way cities design, budget, and build for the future.

President Donald Trump—and the leaders appointed by and aligned with him—not only refuses to acknowledge the impacts of climate change, he wants government-funded scientists to stop studying it. But when city leaders are unable to understand that the reality of extreme heat or sea level rise are only a few decades away, they’re unable to invest in appropriate solutions like infrastructure and technology.

As scientists become the people forging the link between climate change and risk, their work now includes sharing that information directly with local governments so cities can prepare for the worst. There’s a new word for this type of planning: resilience. And it’s becoming a big part of the way cities design, budget, and build for the future.

Barack Obama was the first U.S. president to acknowledge and act upon the consequences of human-caused climate change, but perhaps more importantly, his administration empowered a diverse coalition of government agencies, from the Interior Department to the Department of Housing and Urban Development, to make climate science central to their work.

Over the last eight years, U.S. agencies like the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the USGS have published some of the world’s most critical climate research, sharing their findings through initiatives like the Climate Resilience Toolkit, U.S. Global Change Research Program, and States at Risk.

These projects translate science into understandable, real-world consequences, and thanks to this government-funded research, scientists can show, using data, which states and cities are most at risk for fallout from climate change. Cities are able to use these recommendations to plan for the future, but also to reduce the burden of climate change-related events as they happen—and those events are becoming more frequent, expensive, and deadly.

Each year since 1980, NOAA’s National Centers for Environmental Information has released a report on the country’s “billion-dollar weather and climate disasters.” These are the extreme weather events that cost states $1 billion or more (adjusted for inflation) and exact a heavy human toll. Since 1980, the number of these events has steadily increased, due to many factors related to urbanization: the general population increase, people moving to coasts, cities sprawling into more susceptible regions, and a dramatically changing climate.

Last year saw the second highest number of billion-dollar disasters since 1980: 15 events that caused 138 fatalities and $46 billion in losses. But what’s particularly troubling is the number of two particular types of disasters: 2016 saw four inland flood events and eight severe storm events, more than any year on record. Both types of events have greatly increased in frequency over the last decade.

While not all extreme weather is caused by climate change, federal research has been instrumental in helping climatologists pioneer a new field called attribution, which attempts to tie extreme weather events to climate change. Flooding, heavy rainfall events, and severe storms are most likely to be attributed to climate change because a warming planet causes the atmosphere to absorb more water vapor. Last year was determined to be the warmest year on record, and the two previous warmest years were 2015 and 2014.

When attribution works together with the “billion-dollar disaster” report, it becomes a risk assessment tool that helps to predict which places are most vulnerable to climate disasters and their economic impacts. So climate research is no longer about predicting some unknown event sometime in the distant future—climate disasters are both the biggest financial liability and the most urgent public health risk facing the country today.

Now cities of all sizes are working with scientists to author long-range strategic climate plans. Back in 2015, the Southern California city of Long Beach tapped NOAA oceanographers at the city’s Aquarium of the Pacific to create a climate resiliency plan that predicts and models the impacts of climate change on the city. Long Beach is using a data-driven approach to determine how climate change will affect the city’s most vulnerable residents: low-income, elderly, and non-English speaking communities.

For Long Beach mayor Robert Garcia, who has a Ph.D. in educational policy, acting on the information scientists presented to him was a given after years of teaching in a university setting. But he’s dismayed that not all policymakers feel the same way. “It’s really important in this environment where there is so much denial about climate change coming from Congress and the federal government and certainly from the president,” he says. “We need to recognize climate change is a real threat to our local communities.”

Trump has named cabinet nominees and senior advisors including fossil fuel industry billionaire Rex Tillerson, climate change denier Scott Pruitt, and anti-science agenda-maker Stephen K. Bannon, who have professed their intentions to pull out of the United Nations’ Paris climate accord, eliminate the Environmental Protection Agency’s regulation of greenhouse gases, and roll back emissions-reducing initiatives like the Clean Power Plan. In December, a member of then-President-elect Trump’s transition team expressed Trump’s desire to defund “politicized” science—namely the work of NASA’s Earth Science Division, a leader in the field of climate science.

Climate science is no longer about predicting some unknown event sometime in the distant future—climate disasters are both the biggest financial liability and the most urgent public health risk facing U.S. cities today.

In tandem with a Republican-dominant Congress, the Trump administration has felt newly empowered to declare a war on science. Pages on climate policy vanished from the White House website without delay after Trump’s inauguration. A Centers for Disease Control climate change summit was abruptly cancelled. EPA scientists were told their climate work must be reviewed by political appointees, introducing partisanship to their research process. Republican leaders of the House Committee on Science, Space, and Technology—which has used its platform to deny global warming—revived an ongoing campaign accusing climate scientists of exaggerating data. House Republicans have introduced a bill to terminate the EPA, and the agency was ordered to delete information on its website making the connection between fossil fuels and climate change.

Within a few weeks, the federal government has emphatically undermined the authority of its own science agencies, and it’s now apparent that tools that have become invaluable for U.S. cities might be permanently eliminated. These moves are both putting cities at risk and leaving them as the first line of defense against the impacts of climate change.

Even before the presidential election, cities all over the world had started working together to combat climate change. Groups like the Compact of Mayors, C40, and Ready for 100% formed alliances to reduce emissions and make the switch to renewable energy. Although 128 countries ratified the UN’s Paris climate accord, which aims to keep the planet’s warming below 2 degrees Celsius, cities claim their localized actions can more directly reach a majority of the world’s residents and be more nimble when it comes to implementing change (although some climate experts dispute that city actions are enough).

Cities also have more in common with each other than countries do. The Rockefeller Foundation initiative 100 Resilient Cities, for example, creates a dialogue among affiliate cities about the best practices for identifying and addressing various risks to their residents. So New Orleans can get guidance from, say, Amsterdam on how to prepare for sea level rise and coastal flooding.

In some of its cities, 100 Resilient Cities funds a Chief Resilience Officer who manages comprehensive climate strategies that connect departments ranging from emergency response to city planning. Marissa Aho, the CRO for the city of Los Angeles, drew from the 100 Resilient Cities network when she convened a symposium proposing solutions to combat urban heat island effect. “We are taking action, for example, by installing millions of square feet of cool roofs and setting other ambitious targets,” she says. “Addressing these issues has multiple benefits across public health, public safety, equity, community greening, and energy efficiency.”

Framing the conversation around resilience allows cities to talk about climate risk in a more holistic way, says Michael Berkowitz, president of 100 Resilient Cities. When preparing for a major flooding event, it’s not just about seawalls and levees, he says, “It’s also about transportation, economic opportunities, the cohesion of community—all of those things are inextricably related,” says Berkowitz. “What resilience says is that bad things can and will happen. Rather than trying to predict each and every one of them, resilience says, ‘How do we strengthen the city as whole?’”

Infrastructure can act as one of these benefit multipliers: A sea wall built to protect a city from flooding might also double as a pedestrian plaza or skate park or amphitheater or sports field. And projects that address many risk factors at once, while also offering a daily asset to the community, can also be used to elicit financial support from government officials who refuse to acknowledge climate change—cities could seek funding for these dual-function projects through something like an infrastructure program, without having the “politicized” science debate.

There’s also a movement to educate lawmakers about resilience. As part of the California Climate Change Symposium, which took place in late January, scientists spent a day briefing incoming California legislators on climate change threats, including saltwater intrusion due to sea level rise and the impact of recent rains on the Sierra Nevada’s snowpack. Bryn Lindblad of the nonprofit Climate Resolve, which helped organize the conference and briefing, thinks the key to reaching leaders is having these kind of community-focused, value-neutral conversations delivered straight from scientists. This allows policymakers from both sides of the aisle to see that climate change is not part of some larger political agenda, she says. “Building resilient infrastructure and planning ahead is not a partisan issue.”

On a rainy February morning, an over-capacity Northern California reservoir opened its emergency spillway for the first time in its history, releasing a muddy wall of water towards the homes of over 188,000 residents, who were later ordered to evacuate. As the dramatic images from Lake Oroville made international headlines, the dam was also being closely watched by scientists like geophysicist Kenneth Hudnut.

As the USGS’s science advisor for risk reduction, Hudnut heads up the Science Application for Risk Reduction, which helps cities understand the hazards, risks, and cost of mitigating natural disasters. SAFRR began by crafting scenarios like the hypothetical 7.8 earthquake on the San Andreas fault that helped demonstrate the need for the region’s early warning system. But it’s recently shifted to encompass scenarios for climate-related events—like the atmospheric river superstorms that pummeled the West Coast for the first weeks of 2017, filling Lake Oroville to the brim.

“For 100 years we’ve been in the mode of ‘let’s see what happens when it happens,’” says Hudnut. “Now we are using science and engineering and technology to intelligently protect those assets and ensure against future losses. We are taking actions to improve our infrastructure, and making it more resilient.”

SAFRR’s ARkStorm scenario—what scientists like to call the “Other Big One”—is based on a particularly devastating 1862 atmospheric river event that inundated parts of California’s Central Valley for up to six months. Downtown Sacramento was navigable only by boat, requiring the temporary relocation of the state’s capital to San Francisco. Scientists believe that the state will see more of this in the future: These are the kinds of heavy-precipitation inland flooding events that are becoming more frequent with climate change.

What the ARkStorm scenario does is take these historical extremes and reimagine them in a future on a warming planet. Thanks to the foresight of hundreds of scientists, economists, engineers, emergency managers, and social scientists, California can now make a more informed decision about which spillways to open and when to tell residents to evacuate. Making the wrong decision about Oroville—or being unprepared for the next voluminous wave of rain the state was about to receive—could have resulted in the type of catastrophic flooding that paralyzed the state 150 years ago.

“It’s only been in the last 20 years that we have been able to see what an atmospheric river is, and forecast it, and tie it to a whole range of geologic and engineering and social impacts,” says Dale Cox, SAFRR’s project manager and one of the ARkStorm scenario authors.

Much of that is thanks to the 20 satellites that have been designed and dispatched by NASA’s Jet Propulsion Lab, in some of the Earth Science missions specifically cited for defunding by Trump. NASA has become a global leader in tracking climate change data like atmospheric carbon dioxide levels and sea level rise. But its satellites now measure regional indicators like soil moisture, groundwater, and snowpack coverage, too—critical tools for California’s water management—and help scientists track atmospheric rivers from space. That’s a vastly different approach to monitoring extreme weather that’s been pioneered just in the last few years.

Without this kind of federally funded research, cities won’t have the data that can help them prepare for the next superstorm—or redesign their aging reservoirs to respond to the new era of extremes.

Without this kind of federally funded research, cities won’t have the data that can help them prepare for the next superstorm—or redesign their aging reservoirs to respond to the new era of extremes. And with a cabinet and agency administrators who won’t declare that these events are going to get worse, there’s less urgency to help cities address these issues before they become deadly disasters.

Just as Trump was elected president, scientists around the world were focusing their attention on a single, terrifying chart. It showed the amount of Arctic sea ice. And it showed that instead of growing, as it normally does in late fall, it was shrinking. Not just melting. Dropping to historic lows, tumbling precipitously, then plunging off the charts.

“This is happening now,” tweeted meteorologist Eric Holthaus, who has posted the chart dozens of times over the last three months with an increasing message of urgency. “Not in 50 or 100 years—now.”

That’s something scientists have been saying a lot lately. During the last decade in the U.S., summers have been hotter, precipitation patterns have been more unpredictable, storms have been more intense, wildfires have been more devastating. Climate change is already affecting cities: flooding expensive real estate in Florida, tainting water sources with toxic algae blooms in Ohio, and changing the way crops grow in California. This is happening now.

In the last few weeks, as climate denial ascended to the highest reaches of U.S. government, the world has entered uncharted territory. The tens of thousands of scientists who study our planet agree what is happening now is not normal. They also agree about what needs to be done to address the threat. They have organized a march on Washington to bring attention to the “politicized” science that Trump’s administration refuses to fund—or even acknowledge. They are warning him that his actions will kill many people and disrupt many more lives.

At the American Geophysical Union’s meeting in San Francisco last December, an interview with California Governor Jerry Brown turned to the presidential administration’s response to climate change—specifically the threat to the federal funding that helps gather the state’s essential climate science. "If Trump turns off the satellites, California will launch its own damn satellite,” he said, to loud applause. "We're going to collect that data."

During the first time that he served as California’s governor in the 1970s, Brown was ridiculed when he floated the idea of a state satellite network—it’s why he was given the nickname “Governor Moonbeam.” But Brown was remarkably prescient. While he may not need to deploy California’s own satellites now, his call to listen to scientists has been echoed by leaders nationwide.

In a critical moment for our uncertain future, when the White House has abandoned the cause, the partnerships between local lawmakers and scientists may be the best hope we have to save our cities. The rallying cry could be heard as Brown addressed the standing-ovation crowd of geophysicists last December: “We've got the scientists, we've got the lawyers—and we're ready to fight.”