But he disappointed European governments and environmentalists in his own country by declining to say by how much - or how quickly.
With the speech at the Earth Summit Plus Five event in New York, President Clinton began a battle to change public opinion in his own country. With only 4 per cent of the Earth's population, the US emits more than 20 per cent of the world's man-made greenhouse gases. That has to change, he said. As the north- east of the US sweltered under a heatwave, President Clinton said the scientific evidence that humanity was changing the climate was clear and compelling. It threatened rises in the sea level, more severe droughts and floods, forest loss and the spread of infectious diseases.
He said the federal government would back a programme to install one million solar roofs on US buildings by 2010. Sunshine will then be used to heat water and generate electricity instead of fossil fuels, which produce carbon dioxide, the principal greenhouse gas.
American output of carbon dioxide has risen by 13 per cent since 1990, even though the US joined with other developed nations at the Rio Earth Summit five years ago in pledging to stabilise annual emissions between 1990 and 2000.
This week, at UN headquarters in New York City, where the follow-up meeting to the Earth Summit is being held, UN nations and green groups have criticised the US. Tony Blair headed the charge on Monday.
But the White House faces intensive lobbying from politicians and fossil- fuel industries at home who claim that curbing emissions would severely damage the US economy. They question whether the threat of climate change is real and suggest that the American way of life, which depends on heavy consumption of oil, coal and gas, is at stake.
While the European Union has pledged to cut its overall emissions by 15 to 20 per cent by 2010, other big industrialised nations have not announced what curbs they are offering. The US is the biggest player in these negotiations, and it was hoped that President Clinton's speech would propose a specific target rather than an unnumbered reduction.
President Clinton also told the UN that for the next five years at least pounds 100m of foreign aid would be directed towards projects which helped developing countries cut their emissions of greenhouse gases.
Mr Clinton will hold a conference in the White House on climate change in the autumn. In the meantime, he will talk to business leaders, trades unions and universities to help him assess what curbs in greenhouse gas emissions the US can offer the world.
Mr Clinton said: "The science is clear and compelling; we are changing the global climate ... we can expect more deaths from heat stress. No nation can evade its responsibility. I applaud the European Union for its strong focus on the issue ... here in the United States, we must do better."Reuse content