With the mix of bluster and incompetence that is fast becoming its trademark, the Trump administration recently unveiled its newest executive order, which was intended to slap down the climate-change programs initiated by Barack Obama. The bluster showed in the president’s spiteful, symbolic decision to unveil this order at the Environmental Protection Agency. The incompetence showed in its failure to hit its own targets. Indeed, for all Donald Trump’s railing about the efforts to curb climate change, nobody in his administration seems to have paid any attention to what they actually are. Obama issued a slew of executive orders about climate change during the eight years of his presidency. Inexplicably, President Trump revoked about half of them but left the other half in place. Since Obama’s orders were intertwined, it’s unclear exactly what applies. Perhaps later executive orders will clarify the executive order that revokes the executive orders, but for now . . . well, let’s say that when I called an environmental lawyer to ask what the net effect will be, he simply laughed. In more nerdy detail: Trump’s order revoked Obama’s Executive Order 13653 of November 1, 2013, which directed federal agencies to “develop, implement, and update comprehensive plans that integrate consideration of climate change into agency operations.” But Trump’s mandate says nothing about, for example, the former president’s Executive Order 13693 of March 19, 2015, which directs federal agencies to integrate climate considerations into their own operations. Or other orders outlining federal agencies’ duties to prevent ocean acidification (caused by rising carbon-dioxide levels), help alleviate climate problems in poor nations, and so on. Possibly the most notable omission is any mention of the U.S. commitment under the Paris climate agreement to reduce emissions. All of these obviously overlap. Which part goes where—nobody knows. Similarly, the Defense Department has been worried about climate change for decades. It has taken many steps toward confronting the issue, culminating in a 2014 roadmap for climate action. Trump’s Defense Secretary, General James Mattis, insisted in his confirmation hearings in January that he regarded climate change “as a challenge that requires a broader, whole-of-government response” and would “ensure that the Department of Defense plays its appropriate role within such a response.” And while Trump revoked Obama’s executive order instructing the Defense Department to prepare for climate change, his own order doesn’t mention the roadmap—or Mattis’s stated policies—which presumably are still applicable.

The second main target of Trump’s executive order is Obama’s Clean Power Plan, which Trump wants to expunge because he suggests that it is unfairly targeting the coal industry. “My administration is putting an end to the war on coal,” he promised on Wednesday. But Trump’s order doesn’t actually rescind the plan. Instead, it begins the process by instructing the E.P.A. to review it. What’s unclear is, (a) whether the Trump administration actually can rescind the plan, and (b) whether it will make any difference if the administration does. It is hard to explain this without getting deep into the weeds. The bad news about this is that you will have to spend a few paragraphs wading through some basic information about procedure. The good news is that at the end of doing so, you will know more about how the government works than the president of the United States does. Here goes: The legal fight over climate change begins in the United States with the Clean Air Act Amendments of 1977. Under the Act, the E.P.A. is required to publish a list of “stationary sources” of air pollution, of which the most important are power plants. Once a facility is on the list, the E.P.A. is required—again, mandated by law—to force the plant to install and use “the best system of emission reduction” that has been “adequately demonstrated.” Video: How Climate Change Could Drown New York City In 2007, the Supreme Court held that greenhouse gases—carbon dioxide, mostly—must be counted as pollutants for the purposes of the Clean Air Act. The decision was contentious, because the drafters of the Clean Air Act obviously did not have climate change in mind (the law was passed before anybody on Capitol Hill had ever heard of it), and because the kind of harm caused by climate change (sea-level rise, droughts) is different from the kind of harm (asthma, cancer) caused by ordinary air pollutants. Nonetheless, the Supreme Court decided that carbon dioxide fell under the purview of the Clean Air Act, which meant that the E.P.A. was legally obliged to deal with it. How the E.P.A. would deal with it was governed by another law, the Administrative Procedure Act of 1946. You know how in movies the new president comes in and promises to perform sweeping actions with a stroke of a pen? The Administrative Procedure Act is designed to thwart this sort of maneuver. The first thing the E.P.A. had to do according to the Administrative Procedure Act was figure out the severity of the issue. It therefore created the Interagency Working Group on the Social Cost of Carbon. This sounds—and is!—super-bureaucratic, but it was also really important. The Interagency Working Group produced a complicated, eye-glazingly dull Technical Support Document that quantified the harm caused by carbon dioxide. With this document in hand, the E.P.A. in 2009 issued an “endangerment finding” that said, basically, that carbon dioxide is bad. Having quantified the harm, the agency now had to regulate carbon dioxide—again, a statutory requirement. The Clean Power Plan was the result. Trump can’t simply wipe out the Clean Power Plan, indeed, because the Supreme Court has declared carbon dioxide to be a pollutant, and therefore the E.P.A. must regulate it. That means the agency can’t throw out the old Clean Power Plan—it has to write an entirely new one. In other words, it has go through the entire process all over again. What’s the first step? Creating a new group that evaluates the severity of the problem. What’s in Section 5(b) of Trump’s executive order? Disbanding the Interagency Working Group on the Social Cost of Carbon and consigning all of its works to the pit of hell. Indeed, the executive order explicitly tells federal agencies to disregard the costs of carbon dioxide. But the first thing the new regulators will have to do is . . . figure out the costs of carbon dioxide. Presumably, the Trump administration will put a good face on this by reconstituting the group under a new name.