The catastrophic outcome of last November's U.S. presidential election is now clear. President Donald Trump's indifference to the risk of climate change, and the actions he is taking because of that indifference, are likely to have consequences that dwarf the significance of his executive order on immigration, his nomination of an arch-conservative to the Supreme Court and, should he manage to achieve it, his repeal of the Affordable Care Act ("Obamacare").

With the exception of launching a nuclear war, it is hard to think of anything a U.S. president could do that is liable to harm more people than last month's order canceling rules issued under former President Barack Obama to freeze the construction of new coal-fired power plants and shut down many old ones. Trump's order followed his pledge to rescind stricter fuel-efficiency standards for cars and trucks, and his announcement that he wants to slash spending on climate science.

Although Trump did not announce the withdrawal of the U.S. from the Paris climate agreement, his actions are likely to prove incompatible with the U.S. government's pledge to reduce greenhouse gas emissions to 26 percent below 2005 levels by 2025. The Paris Agreement, signed by 195 countries, is our last real chance of keeping global warming to less than 2 degrees Celsius above pre-industrial levels. Even 2 degrees is too much for the inhabitants of low-lying island states. Many of these states were pleading for a 1.5-degree limit — without which some will disappear beneath the ocean.