Last month, deep in a 500-page environmental impact statement, the Trump administration made a startling assumption: On its current course, the planet will warm a disastrous seven degrees by the end of this century.
A rise of seven degrees Fahrenheit, or about four degrees Celsius, compared with preindustrial levels would be catastrophic, according to scientists. Many coral reefs would dissolve in increasingly acidic oceans. Parts of Manhattan and Miami would be underwater without costly coastal defenses. Extreme heat waves would routinely smother large parts of the globe.
But the administration did not offer this dire forecast, premised on the idea that the world will fail to cut its greenhouse gas emissions, as part of an argument to combat climate change. Just the opposite: The analysis assumes the planet’s fate is already sealed.