In the wake of House passage of energy and climate legislation, the big question confronting the Senate is whether to act this year — which will no doubt involve much effort and compromise on all sides — or whether to wait.

[IMGCAP(1)]Those who urge delay argue that maybe when the economy gets better — then we can deal with climate (even though limits on CO2 would not begin until 2012 in a better economy). Maybe if we delay, they suggest, the science will show that things aren’t as bad as we thought. (In fact, the science shows quick action is needed or impacts and costs will get much worse.) Maybe if we delay, we will develop a better approach that taxes industry by eliminating free allocations. (Just wait for that tax bill with no loopholes.)

But waiting won’t work this time, because the climate and energy debate is now fundamentally different in three respects.

First, Congress no longer faces the choice of acting on climate change — or having nothing happen. Since the Supreme Court ruling of 2007 that CO2 is a pollutant under the Clean Air Act, the question is whether climate change will be addressed by Congressional action or Environmental Protection Agency regulation. There is widespread agreement that Congressional action is preferable, but President Barack Obama has made it clear that the EPA will regulate emissions on the basis of science if Congress does not act. And the EPA’s existing regulatory authorities are much too blunt to deliver a solution as cost-effective as the proposed cap-and-trade model.

Second, major business interests have embraced specific mandatory legislation this year. The Edison Electric Institute, representing the nation’s major electricity providers, essentially backed the House bill, as have many other major U.S. companies. They know the rest of the world is moving on energy technology innovation — spurred into use by carbon markets — and we can’t be left behind.

Companies also need certainty to make much-delayed investments in long-term energy generation, investments stimulating job creation that is desperately needed during this economic downturn. This new coalition can only support legislation that provides access to the least cost reduction opportunities — which can only be seized through a cap-and-trade approach with international and domestic offsets.

Senators are taking notice of this major new business coalition favoring climate legislation. But unfortunately, most press accounts misread this industry support. Too many reporters took the bait of the far left that decried the House bill as riddled with “giveaways— and “loop-holes— for industry. As Harvard’s Dr. Rob Stavins has pointed out, free allocation of a good portion of allowances to minimize ratepayer impacts and regional differences is a legitimate policy choice — and it is no giveaway or loophole, as the reduction targets still require significant action and investment.

Third, the science continues to show that there are serious climatic and economic risks if we delay longer. Impacts are already in evidence across the U.S., from stronger hurricanes in the Gulf of Mexico to melting permafrost in Alaska to dying forests in the Rockies among many other impacts. Delay not only exposes our children to higher risks of adverse impacts from climate change — it also saddles them with a much harder, more expensive problem to clean up. Climate change is different from most air pollution issues in that the main problem is not just daily or yearly emissions — it is rather the buildup of concentrations in the atmosphere over time.

Annual emissions add to historic concentrations, which are the culmination of decades and even a century of emissions. This facet of climate science has profound implications for policy: The longer we wait, the more we have to do to correct the problem, and the more expensive the cleanup will be. Delay isn’t free — it just hurts our children more, because they will end up paying the tab.

This year, America faces a historic international opportunity to restore our leadership. The key to gaining developing country commitments in Copenhagen is whether we are willing to demonstrate bold action at home before December.

The Senate has an unprecedented opportunity to lead — not just the nation but the world — in establishing a new era for clean energy growth and addressing climate change. It is up to the Senate now.

Dirk Forrister was chairman of the White House Climate Change Task Force under President Bill Clinton and is now managing director of Natsource, an environmental fund management company.