To advocates of action on global warming, the Copenhagen summit represents the last, best chance to slow and eventually reverse the growth in greenhouse-gas emissions before climate change begins to spin out of control. To skeptics of climate change, many of whom will attend the conference, Copenhagen is the last defense of another kind — against the growing global momentum to reduce greenhouse-gas emissions, an undertaking they think could cripple the international economy. Either way, it is likely to be the most important international environmental conference in history, its importance bolstered by President Barack Obama’s decision to appear at the end of the summit (initially he had planned to arrive at the start), when the most significant discussions occur and a deal might actually be made.

1. Will the U.S. lead? The U.S. delegation to climate summits under former President George W. Bush played the spoiler. Not only were American diplomats generally opposed to building a global consensus on reducing carbon emissions, they actively seemed to enjoy gumming up the works, walking out in the middle of negotiations during the Montreal summit in 2005, for instance, and nearly torpedoing the entire process two years ago in Bali.

2. Will China and India follow? Historically, the U.S. may be the world’s biggest carbon emitter — responsible for more than a quarter of the man-made CO2 in the atmosphere — but developing nations led by China and India will be responsible for the majority of future emissions. At the same time, those nations still have low per capita emissions, and under the Kyoto Protocol, they haven’t been required to take any verifiable actions to control emissions. Until recently, they haven’t shown much interest in doing so, but that may now be changing.

3. The two-step tango. Back in 2007 on the sunny Indonesian island of Bali, negotiators worked out the “Bali road map,” a series of steps toward a successor to the Kyoto Protocol that would guarantee a new global climate treaty by the 2009 conference in Copenhagen. Well, road map or not, the international community got a bit delayed — in part due to the fact that Obama has had less than a year to turn around U.S. climate policy — and no one expects an actual treaty to be negotiated and signed in Copenhagen.

4. Seeing REDD on deforestation. The loss of tropical forests plays a major role in climate change, contributing about 15% of global greenhouse gases, according to the most recent estimate. But deforestation has an environmental impact that goes beyond climate change — tropical forests are home to a wealth of diverse species, and when the trees are lost, wildlife follows.

5. Financing adaptation. Combating climate change isn’t just about reducing carbon emissions. Global warming is coming even if we do act fast, and developing nations will bear the brunt of the impact. That’s why another leg in the global treaty will address funding to help developing nations adapt to climate change — whether that means the building of seawalls, aid for agriculture during increasing droughts or the ability to better respond to natural disasters. “We need clarity on long-term finance for developing countries,” says de Boer.

As the talks begin in Copenhagen, there’s reason for climate-change advocates to feel optimistic — for the first time world leaders will be sitting down to focus solely on global warming — and reasons to worry that everything will collapse. The one thing we know is that this summit will help decide whether the world takes on climate change, or continues risking business as usual. “This is our last chance to avoid a dangerous 2°C of warming,” says Dan Lashof, the director of the Natural Resource Defense Council’s Climate Center. One way or another, now is the time to act.

Source: Time