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President Trump presents himself as a climate skeptic, but perhaps he doesn’t even know what climate change is. That’s a possibility raised by my colleague Philip Bump this week after Trump, on a visit to Britain, responded to a question about climate change by emphasizing his concerns for “very, very crystal clear, clean water and clean air.” He also spoke about companies and countries elsewhere polluting the oceans.

Scanning his record of remarks about climate change, Bump concluded that Trump “may not actually understand the mechanism that is warming the planet” and that he routinely conflates the concerns of environmentalism, writ large, with concerns over carbon emissions warming the planet. (Never mind, of course, that his administration has set about gutting environmental protections and regulations, as well.) “Trump’s suggestion that clean air and clean water are ‘a big part of climate change’ is accurate only with a remarkably generous interpretation of his comments,” Bump noted.

Trump’s obtuseness came the same day a new report confirmed that 2019 marked a record year in global greenhouse gas emissions. After a gradual decline, the United States’ energy-related CO2 emissions rose 2.7 percent last year, a consequence of Trump’s rollback of Obama-era climate regulations.

None of this is surprising for a president who turned his back on the landmark Paris climate accord and who will leave climate conspicuously off the agenda when he hosts the Group of Seven summit next year. The White House’s rejection of collective climate action casts a huge shadow over the politicians, policymakers and scientists convening in Madrid this week and next for a U.N. conference on climate change. Some activists have branded Trump and other climate-skeptic, right-wing nationalists such as Brazilian President Jair Bolsonaro as enablers of “ecocide.” Other U.S. officials are still attempting to fill the breach: House Speaker Nancy Pelosi (D-Calif.) is slated to lead a congressional delegation to the talks, though it will have no formal role in the proceedings.

“Congress’s commitment to action on the climate crisis is iron-clad,” Pelosi said in a statement. “This is a matter of public health … of our children, of the survival of our economies, of the prosperity of the world, of national security, justice and equality. We now must deliver deeper cuts in emissions.”

The apocalyptic warnings are once more being sounded in Madrid. U.N. Secretary-General António Guterres scolded the world’s major economies for their “utterly inadequate” steps in reducing emissions and declared over the weekend that humanity faced a “point of no return,” a warning that echoed a recent U.N. report that called for dramatic and drastic action by governments. According to the report, global greenhouse gas emissions need to start falling by 7.6 percent each year starting next year — a rate that’s nowhere in sight, not least because of a lack of White House leadership on climate.

In the meantime, international organizations are calling attention to climate change’s many victims. The humanitarian group Oxfam calculated that, on average, more than 20 million people were displaced by extreme weather events each year of the past decade. “Today, you are seven times more likely to be internally displaced by cyclones, floods and wildfires than by earthquakes and volcanic eruptions, and three times more likely than by conflict,” Oxfam said in a report published this week.

The math for calculating the scale of a putative global climate refugee crisis is a bit fuzzy. Estimates forecast that the number of environmental migrants by 2050 could range from 140 million to as many as 1 billion people. In a recent Democratic presidential debate, Sen. Bernie Sanders (I-Vt.) pointed to “hundreds of millions of climate refugees” in the “years to come.”

Whatever the case, it is already apparent that a changing climate is stoking more extreme weather patterns, which in turn are displacing or crippling countless vulnerable communities around the world. A study by Save the Children concluded that, in east and southern Africa this year, floods, landslides, drought and cyclones contributed “to at least 33 million people in the region — or 10% of the population across ten countries — being at emergency levels of food insecurity or worse.” That includes more than 16 million children.

Environmental and development groups are hoping to push wealthier countries to build a fund that can support poorer nations afflicted by climate disaster. But, in an era of climate crisis, many communities may need wholesale resettlement. Drought and shifts in weather have fomented migration crises from Syria to Central America. Recognizing this, House Democrats put forward legislation that would create a federal program that would take in a minimum of 50,000 climate refugees every year in the United States.

It’s a bill that will never pass under Trump, who has reduced U.S. refugee resettlement to record-low levels and even thwarted temporary protected status for citizens of the Bahamas fleeing the ravages of Hurricane Dorian this year. Given the Trump administration’s hostility to migrants and skepticism of climate change, there may be no more forlorn a plight than that of a climate refugee.