SINGAPORE — Researchers from around the world meet in Denmark this week to discuss the latest scientific findings on climate change, following recent warnings that the severity of global warming this century will be much worse than previously expected and that changes to the climate will be difficult if not impossible to reverse for centuries to come.

The three-day international research congress at the University of Copenhagen is sponsored by a consortium of 11 research universities in Europe, the United States, Asia and Australia, including the University of Tokyo. It is part of the leadup to a conference of world leaders in Copenhagen in December to try to agree on a global treaty or framework to replace the Kyoto Protocol to combat global warming.

That protocol, which expires in 2012, has had limited impact partly because it only binds about three dozen developed economies to cut carbon dioxide and other greenhouse-gas emissions blamed by many scientists for causing an increase in temperature, more extreme weather, the spread of disease and rises in sea levels. The two biggest emitters, China and the U.S., are not in this group. Nor are emerging economies such as India, Indonesia and Brazil, whose recent growth and development have made them important emitters.