Sometimes things don’t work out the way we expect. New York Mayor Michael Bloomberg today announced a $50 million gift to the Sierra Club. His motive? “Coal is a self-inflicted public health risk…and the leading cause of climate disruption.”

But what will actually come out of the Bloomberg gift?

1) The Sierra Club is likely to be more effective in attacking the U.S. coal industry;

2) U.S. coal production will therefore not reach the level it might have without the gift;

3) U.S. coal exports are then unlikely to reach the level they might have;

4) Top importers, such as China and India, will have to mine more of their own coal or import more from non-American sources;

5) Top exporters, such as Indonesia and Russia, are likely to export more.

There are other important implications of American coal production, like job growth and cheaper electricity. But the environmental component is the one most often based on wish fulfillment. Just because you don’t like coal, Mr. Mayor, doesn’t mean it will go away.

The punch line: Coal production in China, India, Indonesia, and Russia (as well as some other major producers) is dirtier than American production. Cut our output and raise theirs and you get more “climate disruption” and other environmental consequences.

One result of the Bloomberg gift to the Sierra Club: greater ecological risk.