The study by researchers at the National Center for Atmospheric Research and the University of Colorado warns continuing economic and technological disparities will make it more difficult than anticipated for developing countries to reduce greenhouse gas emissions, and that underscores the challenges that poorer nations face in trying to adapt to global warming.

"There is simply no evidence that developing countries will somehow become wealthier and be in a position to install more environmentally friendly technologies," said Patricia Romero Lankao, an NCAR sociologist and lead author of the study. "We always knew that reducing greenhouse gas emissions was going to be a challenge, but now it looks like we underestimated the magnitude of this problem."

As a result, most industrialized nations, as well as developing countries with growing economies, are increasing their emissions of carbon dioxide, the researchers said. Overall, global emissions grew at an annual rate of 1.3 percent during the 1990s and at 3.3 percent from 2000 to 2006.

The study, funded by the National Science Foundation, appears in the journal Climate Research.