Washington ? The Bush administration acknowledges that global warming poses serious problems, but senior officials speaking at a climate-change policy conference Tuesday said there still are numerous uncertainties about global warming’s cause and effects. They urged caution in committing the country to long-term solutions that might hurt the economy.

The three-day, administration-sponsored conference takes place in a year that has seen several global warming scares. An Antarctic ice shelf the size of Rhode Island shattered and collapsed into the sea in March, and Bolivian Andes glaciers are melting at an alarming pace.

Administration officials say the nation shouldn’t panic and make unwise decisions. President Bush has called for a decade of research before the government commits to anything more than voluntary measures to stem carbon dioxide and other greenhouse gas emissions from industry and vehicles that have been closely tied to global warming.

“I don’t think there’s any disagreement that human activity has substantially contributed to the amount of CO2 (carbon dioxide) in the environment,” said John Marburger, the White House science and technology adviser. “What we are arguing is that we need more information to have a clearly articulated regulatory policy that is practical, that’s affordable and doesn’t put the economy at risk.”

But some environmentalists say there is more than enough scientific data from a variety of credible panels to make informed policy decisions.

They questioned whether the conference was simply window dressing for an administration that has decided to oppose any mandatory limits on industrial greenhouse gas emissions, such as those contained in the Kyoto Protocol, an international global warming treaty, or an attempt to put off tough decisions until after Bush leaves office.

“This would have been a good program if it were still 1990,” said Jennifer Morgan, a climate change expert with the World Wildlife Fund. “Over a decade of research has been done in the United States and internationally to make the case for climate change action, so we don’t need to wait for further science to take action. The U.S. is working in a time warp.”

Over the past decade, the UN-sponsored Intergovernmental Panel on Climate Change has produced three comprehensive studies on the cause and effect of global warming, warning of the potential for large-scale and irreversible changes.

They include reductions in the Greenland and West Antarctic ice sheets as well as a substantial slowing of the circulation of warm water in the North Atlantic.

The Clinton administration prepared a National Assessment on Climate Change that provided a region-by-region assessment of the potential effect of global warming on the United States.

In June 2001 the National Academy of Sciences concluded in a review of existing data that global warming was a real problem caused, at least in part, by man-made pollution that could well have a “serious, adverse” impact by the end of the century.