Trump’s retreat on climate policies forces cities to step up efforts to protect at-risk populations from deadly summer heat waves.

Sweat, beads the size of pearls, bubbled on Malik’s face and rolled down his shirtless torso as he trudged through a downtown Washington, D.C. park on a recent afternoon. We locked eyes as our footfalls crossed a paved path.

“Brother, it’s hot out here, ain’t it?” he said. I nodded agreement and wiped my own sweating brow. The heat provided two strangers a moment of bonding in weather-related distress. Summer was a few days away from its sultry debut, but the mercury redlined at that moment above 95°F. That’s the magic number at which D.C. officials to declare a heat emergency and open cooling centers for people who need to escape the heat.

Malik told me he was homeless, living “all over, and nowhere specific.” On hot days, however, he sought refuge in the park because the trees were tall and shade expansive. “It’s as cool out here as anywhere I could be,” he said.

Hotter weather is coming, not only this summer but in years to follow. Deadly waves of summer heat are likely to be a grave concern in future decades, according to a recently published Nature Climate Change report. “An increasing threat to human life from excess heat now seems almost inevitable, but will be greatly aggravated if greenhouse gases are not considerably reduced,” the report stated.

What’s worse, the federal government is turning its back on erstwhile efforts to abate climate change, a development that almost guarantees that temperatures will continue to rise in future summers. As my ThinkProgress colleague Natasha Geiling noted in a recent article, the Trump administration has made it clear in word and deed that the environmental protections established during the Obama administration will not be maintained.

In a sweeping order issued in March, President Donald Trump reversed executive actions requiring federal agencies to both account for climate change and prepare for its impacts. The order also began the process of dismantling the landmark Clean Power Plan, an Obama-era policy that mandated emissions reductions from coal-fired power plants.

Since then, the administration has asked courts to delay arguments over a rule that prevents coal-fired power plants from releasing heavy metals, like mercury, into the environment, and delayed enforcement of a stricter ozone pollution standard. In June, Trump announced he was withdrawing the U.S. from the historic Paris climate agreement — a move that earned swift rebuke from cities across the country.

In short, the nation’s most vulnerable populations — the poor, homeless, elderly, and communities of color, who tend to be disproportionately concentrated in cities and already bear the brunt of pollution — could suffer the most because of Trump’s ignorant and mean-spirited polices.

There’s a term for this: the climate gap, defined as “the disproportionate and unequal impact of the climate crisis has on people of color and the poor” in a 2009 study by researchers at the University of Southern California. One shocking finding in the report noted that African Americans in Los Angeles, California have a projected heat-wave mortality rate that is nearly twice that of the average for all other city residents. The report concluded:

Policymakers have a clear choice: ignoring the climate gap could reinforce and amplify current as well as future socioeconomic and racial disparities. On the other hand, policymakers can proactively close the climate gap through strategies that address the regressive economic and health impacts of climate change, and that lift all boats by ensuring that everyone shared equally in the benefits of climate solutions, and no one is left bearing more than their fair share of the burdens.

Left without federal support, municipal officials across the United States say they’re doing all they can to protect residents. When temperatures boil over to mid- to high-90s, officials in Los Angeles County, New York City, Washington, D.C., Boston, and Phoenix told me they have plans to spring into action, opening cooling centers in publicly accessible government buildings, homeless shelters, and senior citizen centers to protect at-risk populations.

Magdalena Ayed, founder and director of The Harborkeepers, an environmental advocacy organization in East Boston, Massachusetts, said in an interview that municipal leaders have reason to be alarmed about the impact of climate change because so many people are threatened by summer’s heat. She said her organization was alarmed by the number of people who live in crowded into wooden, triple-decker houses — often five or six families together — through increasingly sweltering summers.

“Many of the people in my East Boston community are immigrants from Central America with language barriers, a lack of access to information about where cooling centers are located, or just an absence of general knowledge about how to stay cool in the summer,” Ayed said in an interview. “Their greatest vulnerability are the social and economic barriers that stem from not having the funds to retrofit houses with air conditioning or energy-efficient windows.”

“Climate change is not just about a problem that is going to happen in 50 years with rising sea levels or the like, but it’s happening now and all around us,” said Cari Olson, assistant commissioner for environmental surveillance and policy with the New York City Department of Health and Mental Hygene. “We are very conscious of this affecting residents in New York, who are facing some serious threats because of climate change.”

In New York City, Mayor Bill de Blasio announced in June a $106 million Cool Neighborhoods NYC program, designed to curb the effect of extreme heat in the city. This summer, health officials will begin awarding $60,000 grants to four community based organizations in a pilot program. Over the course of the two-year program, the city anticipates spending $240,000 in the South Bronx, Harlem, and Central Brooklyn, Olson said. The “Be A Buddy” program will make funding available for community-based organizations in the targeted neighborhoods to check on residents and assist them with getting air conditioning in their homes or making sure they’re comfortable when the heat reaches dangerous levels.

“We need to take these actions on the city level in the absence of federal leadership,” Olson said. “But more, much more needs to be done because local governments can’t reach all of the people in the city who need help.”

Like Malik.

My heat-suffering friend in that Washington park said it seemed to him that every summer seems hotter than the one before, but he said he didn’t have any idea why. It just seemed so to him. Our chance meeting was brief and I left him with a lingering concern of what lies ahead for him as the summer heat roars to its infernal zenith. Judging from his appearance at the start of this hot season, I feared the worse is to come.

“I don’t know about any programs or shit like that, man,” he told me. “I don’t know what else to do, but just stay in the shade and try to be cool.”