President Obama didn’t do enough at Copenhagen to meet the legitimate demands of developing nations, especially the poorest of the poor. And while he deserves credit for moving the United States back in a positive direction on global warming after eight years of the know-nothingism of George W. Bush, he has adopted some of Bush’s scolding-parent tone.

The Obama administration has its own self to blame for much of the acrimony in Copenhagen.

His administration flat-out rejected the idea of the industrialized nations paying reparations to the rest of the world for the damage they’ve inflicted on the planet.

Nor did the Obama Administration offer nearly enough to developing nations to encourage them to use non-polluting technologies. Obama promised $10 billion by the year 2012. That comes to just 0.28 percent of the U.S. budget for next year.

Then, seeming to act in a generous manner while actually behaving like a bully, he said he would “engage in a global effort to mobilize $100 billion in financing by 2020, if – and only if –it is part of a broader accord” to his liking.

As he did in Oslo for the Nobel Peace Prize, in Copenhagen Obama talked about the United States doing the right thing not just because it’s right but because it’s in Washington’s “self-interest.”

In Oslo, he said rebuilding Europe, Japan, and South Korea after World War II was in the “enlightened self-interest” of Americans.

In Copenhagen, he said, “We’re convinced, for our own self-interest, that the way we use energy . . . is essential to our national security.”

Yet there comes a time when doing the right thing can’t always be squared with American selfishness. That time is now.

It was, after all, American selfishness and gluttony that polluted much of the earth. And now, American stinginess is preventing the kind of cleaning up that is necessary.

On global warming, the United States should do what is just – and not simply what is in its “self-interest.”

Washington should pay reparations to those nations that contributed least to global warming but that are suffering, and will be suffering, the most because of it. This sum should exceed the measly $10 billion Obama has offered developing nations to go green and go clean.

If Obama had made such a generous offer, he would have been greeted more favorably in Copenhagen.