Among the many pressing issues that President-elect Barack Obama will face when he takes office in January is climate change, which he has called an “immediate threat” and warned has made Earth a “planet in peril.” In an effort to prevent and reverse the problem, he supports a so-called cap-and-trade scheme similar to one now in effect in the U.S. Northeast and the European Union.

Under such a plan, the government sets an overall limit on the amount of pollution allowed and polluters, such as power companies, are sold or given permits to pollute. Those who emit less pollution thanks to a new wind farm, for example, can then sell their excess pollution permits to other companies struggling to meet their quotas. That ensures that the industry stays within the overall emission limit, which declines over time.

On the stump, Obama outlined such a system to cut U.S. emissions of carbon dioxide (CO2) and other greenhouse gases to 1990 levels by 2020 and to 80 percent below 1990 levels by 2050; the plan also included using monies raised by auctioning these so-called permits to pollute to fund renewable energy alternatives and other infrastructure upgrades.

In fact, renewable energy seems to be the linchpin of the Obama climate change plan: he has called for 10 percent of all U.S. electricity to come from renewable resources, such as the wind, sun and hot rocks (the U.S. derives 8 percent of its electricity needs from such resources presently, if hydroelectric dams are counted) by the end of his first term. All told, he has pledged $150 billion over 10 years as part of a renewable energy package (that also might double as a stimulus package).

According to the Obama plan, such an investment could create at least 5 million “green collar” jobs to replace industrial “blue collar” jobs lost in recent decades as steel mills and factories closed. In published interviews, he has referred to such a move as his “number one priority. ”

Obama has made clear, though, that he's not entirely opposed to the old way of doing things. He supports offshore oil exploration in areas where it is already allowed but that oil companies have yet to drill. He opposes  exploration in pristine areas such as the Arctic National Wildlife Refuge (ANWR).

Obama has also  indicated that  he wants to help out coal producing regions in West Virginia, Wyoming and other states by speeding the development of carbon-capture-and-storage technology. Such “clean coal” technology works by first capturing the CO2 from the coal and then storing it deep underground. The initial U.S. effort, dubbed FutureGen and planned to be built in Mattoon, Ill., the president-elect’s home state, was cancelled in February due to high cost.

Obama’s Illinois roots may also prompt  his continued support for corn-based ethanol, something he has called a good “transition technology” away from fossil fuels. Critics note, however, that it takes almost as much fossil fuel (in the form of fertilizers and tractors) to grow the corn for ethanol as the fuel yields—and threatens to pit gas tanks of the haves against the stomachs of the have nots. Some of his campaign indicate that he's also likely to raise federal fuel efficiency requirements and to push American automakers to re-tool to make plug-in electric-gas hybrids and other alternative fuel vehicles.

Of course, climate change and renewable energy aren’t the only environmental issues the new administration must tackle. There’s also the matter of dwindling numbers of mammals, amphibians and a whole host of other animals worldwide. There’s global deforestation. And there’s the  matter of environmental justice: placing toxic waste dumps and other hazardous operations in areas where people are too economically disadvantaged to resist or don't because they hold the promise of much-needed jobs. Poorer communities pay a disproportionate price for environmental catastrophes, whether the aftermath of Hurricane Katrina or the burden of living atop polluted land from the Alaskan Arctic to Alabama. How an Obama administration will address such issues remains to be seen.

Meanwhile, the Bush administration still has a few months to push through its own environmental agenda, including weakening the Endangered Species Act and allowing more pollution from power plants. And Obama can count on opposition as he tries to move forward with any energy or climate regulations from conservative Republicans, including the likes of Sen. James Inhofe, who won re-election in Oklahoma and has called climate change the “greatest hoax ever perpetrated on the American people.”

Obama has pledged  to make energy transformation a top priority and will likely re-engage the U.S. in international negotiations to combat climate change. He’ll be starting out in the climate change hole (thanks to all the CO2 spewed as part of his campaigning) but even engaging the issue would be a big change from the past eight years.