Senators trying to craft bipartisan climate legislation offered a revised proposal Thursday that would add incentives for building nuclear power plants and open the way for expanded oil and gas drilling off the nation's coastlines in hopes of attracting wider support.

The new framework for a Senate climate bill would ease back requirements for early reductions of greenhouse gases. It calls for cuts in the range of 17 percent by 2020, instead of 20 percent, similar to reductions already approved by the House and what Obama will call for at an international climate conference in Copenhagen.

"We would like to underscore the fact that the framework we are releasing today is a starting point for our negotiations going forward," said Sen. John Kerry, D-Mass.

The framework provided only a broad view of what a compromise bill would include with details to emerge early next year. But it reflects a widespread view that the climate bill that advanced out of committee in early November would need to be significantly revised for any hope of getting bipartisan support from at least 60 senators.