In a June 3 speech declaring victory over Sen. Hillary Clinton for the Democrat presidential nomination, Barack Obama's rhetoric peaked in a line for the ages: "This was the moment when the rise of the oceans began to slow and our planet began to heal," he said of what Americans will tell their children generations from now.

Critics pounced on the statement, some quoting satirically from the Gospels: "Who is this man that even the wind and waves obey him?"

But John McCain's rhetoric on halting the effects of climate change is not far behind. The Republican presidential nominee has suggested that an act of Congress to curb carbon emissions in the United States could "prevent catastrophic global warming."

Indeed, both candidates outline plans on their respective campaign websites for dramatically reducing the country's greenhouse gas emissions in the interest of avoiding worldwide calamity. Obama's plan calls for 80 percent reductions by 2050. McCain's only slightly less ambitious strategy aims for a 66 percent drop in that same time frame.

The primary method for accomplishing such radical change in the nation's emission levels: cap-and-trade. A dirty word in many conservative circles, the cap-and-trade system gives corporations incentives to find and implement carbon-reducing innovations on their own. It assigns hard caps to large businesses and allows the sale of so-called carbon credits should any business manage to preserve some of its allotted quota.

The idea is meant to foster gradual reductions with minimal strain on the economy. Companies able to reduce their carbon footprint can profit by selling off credits to those that cannot. Trouble is, it doesn't work.

Throughout Europe, the cap-and-trade system has raised energy costs, stunted economic growth, and promoted outsourcing of emissions and jobs to cap-free nations like China or India. The result: Global emissions remain unchecked, while some European countries absolve their guilt with a false sense of environmental piety.

Both Obama and McCain recognize the problem of emissions outsourcing but believe the United States must model climate change policy to convince China and India to follow. Never mind that western cap-and-trade programs are a boon to developing economies, providing greater incentive to avoid all environmental regulation.

What choice then does the American voter have? The candidates from both major parties are intent on passing cap-and-trade legislation. Still, there are differences.

Obama's environmental stance contains measures in line with the hard green constituency within the Demo-cratic Party. For example, he opposes the U.S. Energy Department's application for a license to operate the nuclear waste dump at Nevada's Yucca Mountain. The Illinois senator has not ruled out future development of nuclear power, but he has expressed sufficient squeamishness about nuclear waste to indicate a less than enthusiastic approach to the one existing technology that could dramatically reduce carbon emissions.

McCain, on the other hand, has set a goal to build 45 new nuclear reactors by 2030, the ultimate aim being 100 new plants to complement the existing 104 plants in the country now. He has called the technology safe and clean, and he points to other nations like France and Belgium, where nuclear power supplies more than half of the energy needs. The Arizona senator supports the use of Yucca Mountain to store the resulting nuclear waste.

Such a push for nuclear power underscores a foundational, even philosophical, difference between the McCain and Obama environmental programs. Whereas Obama's green agenda reflects suspicion of big business and devotion to planetary preservation for its own sake, McCain's environmental positions put economy over ecology. The policy proposals of the respective candidates on environmental matters beyond climate change consistently reflect that distinction.

In the recent debate over offshore drilling, McCain reversed his longtime support of a federal moratorium on the practice in light of market realities. Rising prices at the gas pump led him to declare emphatically that the country must tap its oil reserves off the coasts of Florida and California.

By contrast, Obama vowed this past June that as president he would keep the moratorium in place due to his desire to "protect our coastline." Faced with overwhelming public opinion that the coastline needs no such "protection," the Democratic nominee has since shifted his position, praising a bipartisan Senate energy plan that includes offshore drilling. But he remains reluctant to back the strategy without equivocation: "What I will not do, and this has always been my position, is to support a plan that suggests this drilling is the answer to our energy problems."

Indeed, Obama is much more enamored with the prospects of alternative energy sources like wind and solar. Included within his energy plan is an ambitious goal to generate 25 percent of the country's energy needs from "renewable sources" by 2025. McCain, likewise, supports developing alternative energy sources, but only as part of an "all of the above" approach that includes expansion of domestic drilling.

But McCain's call for tapping U.S. oil supplies is not comprehensive. He remains opposed to drilling in Alaska's Arctic National Wildlife Refuge, a position that puts him at odds with much of the Republican base and even his own running mate, Alaska Gov. Sarah Palin. McCain's defense: "ANWR is a pristine place, and if they found oil in the Grand Canyon, I don't think I'd drill in the Grand Canyon."

Many residents of Alaska believe a shift in McCain's position is only a matter of time now that their governor has joined the ticket. Palin, whose reputation as an unbending bulldog is outdone only by her penchant for winning political debates, is a fierce advocate of drilling in ANWR. She says the environmental impact would be minimal, effectively equivalent to a person sticking their big toe into the yard of a typical residential lot.

Having Palin in his ear could move McCain in more ways than one on environmental issues. She led Alaska into suing Interior Secretary Dirk Kempthorne last month over the Bush administration's decision to list polar bears as a threatened species under the Endangered Species Act. Palin believes the listing unnecessary and detrimental to oil and gas development on the state's North Slope.

On the record

Climate change

Obama: Proposes cutting greenhouse-gas emissions 80 percent by 2050 with an economy-wide cap-and-trade program.

McCain: Proposes cutting greenhouse gas emissions 66 percent by 2050 with a cap-and-trade program; small businesses would be exempt.

Domestic drilling

Obama: Considers drilling an environmental detriment that cannot solve energy problems, but has grudgingly halted his opposition to it in light of the public's overwhelming support; still opposes drilling in ANWR.

McCain: Favors drilling offshore due to high gas prices; still opposes drilling in ANWR, but has stated he will "go back and look at it again" due to "this changed economic environment."

Alternative energy

Obama: Proposes spending $150 billion over the next decade to promote development of clean energy and to create 5 million jobs; open to nuclear power as part of the solution but opposes storing waste at Yucca Mountain.

McCain: Proposes building 45 new nuclear plants by 2030 and reopening Yucca Mountain for storage of the waste; plans to auction off emissions permits and use the proceeds to fund the development of low-carbon technologies.