Leading environmentalists in Washington are ecstatic about most of President-elect Barack Obama’s newly announced cabinet choices, though a closer look suggests that greens may soon be unhappy with the Obama administration’s positions on greenhouse gas emission cuts, nuclear power, so-called “clean coal” and other key issues.

More than any president in US history, Obama seems to understand both the threat global warming poses and the economic opportunities it presents. Obama gave the climate issue unprecedented emphasis during his campaign, most notably on election night, when he called “a planet in peril” one of the three biggest problems awaiting him as president (giving it equal billing with “the greatest economic crisis in our lifetimes” and the wars in Iraq and Afghanistan). As president-elect, he has promised “a massive effort” to invest in green energy as a way to heal both the economy and the atmosphere, as well as a vigorous return of US leadership on international climate negotiations. Now, with his cabinet selections, Obama has given some indication of how he hopes to pursue these ambitions.

The most important picks so far include Hillary Clinton as secretary of state, from which post she will oversee America’s participation in the negotiations in Copenhagen next December on creating a successor to the Kyoto treaty; Stephen Chu as secretary of energy, an agency whose budget is mainly devoted to nuclear weapons but that takes the lead on energy policy; Carol Browner as a special assistant to the president, who will have the job of coordinating energy and climate change policy across the administration; Lisa Jackson as administrator of the environmental protection agency, which is responsible for enforcing US environmental laws and regulations; Ken Salazar as secretary of the interior, who will oversees public lands and endangered species issues; and Bill Richardson as secretary of commerce, who will play an important role in Obama’s green economic policies.

Green activists have been far more enthusiastic about these picks than their counterparts in the spheres of economics and foreign policy have been. Obama chose a “Green Dream Team,” gushed Gene Karpinksi, the president of the League of Conservation Voters. Anna Aurilio, the director of the DC office of Environment America, told the environmental website Grist, “It’s pretty clear that President-elect Obama’s picks represent a 180-degree change in terms of what direction they’re going to be heading on critical issues facing the country.” Referring to Browner, who was the EPA administrator during the Clinton administration and before that a close aide to Senator Al Gore, Aurillio said, “[Obama] couldn’t have picked a better person.” Joseph Romm, a former department of energy official who now writes the indispensable blog Climate Progress, was equally enthusiastic about Chu, calling him “a terrific choice” because of Chu’s strong views on climate change, his experience at running the Lawrence Berkeley Lab, the most important renewable energy lab within the DoE, and his reported skepticism about coal’s future in a carbon-constrained world.

Karpinski, Aurillio and Romm are three of the most tough-minded but level-headed environmentalists in Washington; their endorsements are worth heeding. And it’s certainly true that Obama’s green team promises a major shift in direction from what Bush and Cheney have pursued, a point Obama seemed to underline in his announcement of Chu, saying that his selection showed that US government policy on energy and climate would “respect science.” But so far, Obama’s positions on climate change–though far, far better than the Bush administration’s–remain at odds with what science suggests is necessary to give the world a fair chance of avoiding catastrophic climate change. Although Obama supports an 80 percent reduction in greenhouse gas emissions by 2050 compared to 1990s levels, he has not made the more important near-term pledge to join the European Union in reducing emissions by 20 percent by 2020. Obama plans only to return to 1990 emission levels by 2020, which will make 80 percent reductions by 2050 unattainable. Nor has Obama embraced Al Gore’s call for a crash program to generate all of America’s electricity from non-carbon sources by 2018; Obama says he wants 25 percent of US electricity to be green by 2025. The biggest question concerns coal. As a candidate, Obama spoke passionately about the need to develop “clean coal,” a phrase invented by the coal industry that has no basis in reality: coal is the dirtiest fossil fuel there is. Nevertheless, Heather Zichal, who will serve as Browner’s deputy in the White House, said on Obama’s behalf as recently as October that Obama is “dedicated” to making clean coal part of America’s future energy mix.

Obama’s pledge that his administration will respect science could, however, shift his policies. No one gives the administration more scientific credibility than Chu, a a Nobel Prize winner (for Physics, in 1997) who ranks among the world’s most decorated scientists. Chu seems likely to ask hard questions about coal, which he has called “my worst nightmare.” He has termed energy “the single most important problem that science has to solve,” adding that while it “would be tragic” if science does not solve such well-funded problems as heart disease and cancer, life would still go on. Energy is different, he said: “If we don’t solve [the energy] problem, life could really change.” According to Romm, Chu understands that better energy efficiency should be the first priority. Most discussion of global warming solutions focuses on solar, wind and other sources of new supply. But as Romm and others have demonstrated, improved efficiency actually provides the fastest, cheapest and most potent alternative to the effect of fossil fuels. If Chu can target government policy accordingly, his impact could be substantial.

But a grounding in science can cut both ways, and environmentalists may be dismayed by some of Chu’s other opinions: he believes nuclear power must be part of the nation’s energy mix. He also supports genetic engineering and nanotechnology as possible solutions. These views place Chu in the scientific mainstream, but they may also reflect his appreciation of the looming prospect of peak oil. Speaking in 2004, he said he expected world oil supplies to plateau within ten to forty years. (The International Energy Agency, the voice of the global energy establishment, announced last week that it expects peak oil to arrive by 2020, while outside analysts believe it will come much sooner, if it hasn’t already arrived.) Chu said better energy efficiency could delay the arrival of peak oil by twenty to eighty years, but “the fundamental problem remains.” To keep the world’s vehicles running, Chu seems drawn to solutions based on solar power and nonfood biofuels, which he explored through the Helios Project during his years at Berkeley.

With one exception, the other Obama picks appear to be consistent with but more promising than those of the Clinton administration, which was long on rhetoric but short on results. Gore blamed the administration’s shortcomings on resistance from the Republican-dominated Congress of the 1990s; now that Democrats control Capitol Hill, Obama’s team has a chance to show more spine and progress. Not reassuring on that front is Obama’s selection of Ken Salazar, Democratic senator from Colorado, as interior secretary. Environmentalists wanted him to choose representative Raul Grijalva of Arizona, a progressive Latino who had fought the Bush administration’s campaign to dismantle conservation laws and regulations. Salazar has compiled an 81 percent lifetime voting record from the League of Conservation Voters, so he’s no Gail Norton. But he endorsed Bush’s selection of Norton to run interior in 2001, according to a statement by the Center for Biological Diversity, the nation’s leading NGO on endangered species. The CBD also accused Salazar of having voted in Congress against better fuel efficiency, for off-shore drilling along the Florida coast and for continued subsidies for ranchers, miners and other commercial interests exploiting public lands.

In the end, though, Obama is the president. What he believes and desires matters more than who he appoints to advise and assist him. And on the defining issue of our time–global climate change–Obama seems to “get it”: he respects the science, he understands how dangerous our present course is, and he has good ideas for how to turn the ship of state around. If his crew serves him well, if he thinks big enough, and if he is pushed by public pressure, Obama could achieve amazing things, and not a moment too soon.