The White House has threatened a veto of the US$27.6 billion bill because its overall spending would exceed President George W. Bush's request by about US$2 billion. The Senate has not yet debated the bill.

The bill also would require oil companies to renegotiate faulty drilling contracts issued by the government in 1998 and 1999 that have allowed them to avoid paying billions in royalties, or be barred from receiving any new leases to drill for oil in the Gulf of Mexico.

The White House "strongly opposes" the provision, saying it could produce legal challenges that might delay future lease sales and would set a bad precedent coming nearly a decade after the government signed the contracts.

By inserting a declaration in the bill that climate change is a "reality," the Democratic-controlled House was trying to move US policy-makers beyond a debate, long stimulated by the Bush administration, over whether there was scientific proof that global warming really is occurring.

A leading promoter of that debate has been Oklahoma Republican Sen. James Inhofe, who has referred to global warming as a "hoax." He chaired the Senate Environment and Public Works Committee until Republicans lost control of Congress this year.

Many scientists worry global warming will produce a series of environmental catastrophes, from more violent storms and the collapse of many species, to worsening food shortages and diseases in some regions.

The climate change commission envisioned by the House bill would make its first recommendations by July 1, 2008 and the panel's work would end in 2009.

A White House statement said the Bush administration was committed to addressing "the important issue of climate change," but that the commission would duplicate government efforts already under way.

Environmental groups have lambasted the Bush administration on global warming, saying it has slowed international progress on controlling emissions thought to cause the buildup of greenhouse gases.