Indeed, the early record of this administration has left our allies with the impression that the president is almost hostile to the notions of protecting the global environment and seemingly divorced from the reality that decisions we make today will have long-term, irreversible, and potentially dangerous consequences.

In March, the White House asked the National Academy of Sciences to evaluate concerns over global climate change and its impact on our environment - apparently to reignite a debate over science rather than solutions.

In an unequivocal rebuke of administration doubts, the scientific verdict has now been reaffirmed: Despite the inherent uncertainty in understanding any system as complex as the global climate, human industry - primarily fossil fuel pollution and deforestation - is causing greenhouse gases to accumulate in the atmosphere and raising global temperatures.

This report offered a compelling assessment that should not be ignored in the president's policy agenda: National policy decisions made now and in the longer-term future will influence the extent of any damage suffered by vulnerable human populations and ecosystems later in this century.

This warning must be a mandate for action, and it comes just in time for President Bush's summit with European leaders - an opportunity to demonstrate leadership previously absent and join our allies in an international effort to protect the environment.

To advance that effort requires more than words abroad about our commitment to addressing global warming - it demands significant changes in the president's agenda here at home.

Only weeks after entering office, the president reversed his campaign promise to cap carbon dioxide pollution from power plants. Accounting for nearly a third of US emissions, they are among the primary causes of global warming.

This reversal dealt a blow to a promising, bipartisan proposal and reinforced the widely held notion among other nations that pressure from polluting industries makes America unwilling to take even modest steps to cut emissions. It's time to renew that promise - and keep it.

The administration must also correct its declaration that the Kyoto Protocol - an international agreement to reduce pollution - is dead on arrival. While many in the international community believe that the Kyoto Protocol is flawed, they also believe it is incomplete and that the administration should improve it at the negotiating table.

The president cast the treaty and the international effort aside with almost no analysis of the situation, eschewing a decade's work by more than 160 nations; now he must commit to the tougher challenge of fixing it. Ultimately, that commitment must be demonstrated in our national policies.

The president has offered the nation a budget and energy plan that by his own forceful statements does not address global environmental concerns. It slashes funding for clean energy technologies, a vital component of any serious plan to address climate change and issues of America's energy independence, setting limits on America's ability to innovate, rather than inspiring technological advances to help our economy and our environment.

By one estimate, the Bush plan will increase our greenhouse gas pollution by as much as 35 percent. This plan must be changed dramatically to meet the challenges of global warming.

When President Bush speaks before European leaders, he should chart a new and responsible course by setting out a framework on climate change that can guide the nation. He should assure us that national policy will be based on science and that he understands that the threat of global climate change is real, recognize that we must lead by cutting emissions at home, state his commitment to crafting an international agreement based on mandatory emission caps, and bring to the table all stakeholders, particularly the private sector and the corporate community - to find the least intrusive, least expensive, and most effective solutions.

Bush should reverse course on the Kyoto Protocol by declaring his intention to finalize the agreement. It is in America's national interest to craft a successful Kyoto Protocol - and to make it work at home and around the world. Significant elements of this international treaty are incomplete and unsettled; so too is the Bush record on global warming, energy, and the environment.

Neither the Kyoto treaty nor the Bush record is lost. Both are today unsatisfactory, both can be rescued - and the successful resolution of the former depends heavily on how history will judge the latter.

Bush would be wise to finish the job on Kyoto and do what his predecessors failed to do. It would be an act of true leadership, with a dramatic impact on the environment for which we are all responsible.