Washington, D.C. ? A new scientific study finds that the absolute worst of global warming can still be avoided if the entire world cuts emission of greenhouse gases the way President Barack Obama and Europe want.

A computer simulation by the National Center for Atmospheric Research in Boulder, Colo., looked at what would happen by the end of the century if greenhouse gas levels were cut by 70 percent. The result: The world would still be a warmer world but by about 2 degrees instead of 4 degrees. Arctic sea ice would shrink but not disappear, and sea level would rise less.

About half the temperature increases and changes in droughts and floods can be avoided compared with a scenario without emission cuts, according to the study, which will be published next week in the journal Geophysical Research Letters. Future heat waves would be 55 percent less intense. Thawing of permafrost in the far north would also be reduced.

The study is one of the first to use computer models to quantify how much of the effects global warming can be avoided, compared to a world if nothing is done about the problem.