The researchers called the finding a ``smoking gun'' discovery that validates forecasts of global warming.

They said the findings confirm that computer models of climate change are on target and that global temperatures will rise 1 degree Fahrenheit this century - even if greenhouse gases are capped immediately. If carbon dioxide and other heat-trapping emissions instead continue to grow, as expected, things could spin ``out of our control,'' especially as ocean levels rise from melting Greenland and Antarctic ice sheets.

The findings were in a study published in the journal Science - the latest report on growing certainty about global-warming projections.

More than 1,800 technology-packed floats, deployed in oceans worldwide beginning in 2000, are regularly diving more than a kilometer to take temperatures and other readings.

Researchers led by James Hansen of the US National Aeronauticals and Space Administration

found that for every square meter of surface area, the planet is absorbing almost one watt more of the sun's energy than it is radiating back to space as heat - a large imbalance. Such absorbed energy will steadily warm the atmosphere.