Reporters, photographers and television crews gather around a TV monitor to listen as U.S. President Barack Obama address delegates at the final day of the UN Climate Change Conference on Friday, Dec. 18, in Copenhagen, Denmark. President Barack Obama plunged into an unscheduled meeting Friday with representatives of nearly 20 nations as world leaders, pressed for time, struggled to reach an agreement on how to curb heat-trapping gasses.
U.S. President Barack Obama speaks during a plenary session at the Bella Center in Copenhagen on Friday.
A German climate activist cries as her hair is cut outside the venue of the Climate Summit in Copenhagen, Denmark on Friday.
Snow and ice are cleaned off a globe on Dec. 17 in Copenhagen, Denmark. The globe is part of an art exhibit set up as nations here seek an agreement to curb greenhouse gas emissions.
Protestors with a group called Lobbyists for Profitable Climate Solutions, one holding fake dollar bills, another holding a sign reading "Stop Global Whining," heckle other demonstrators near the venue of the U.N. climate talks in Copenhagen on Dec. 16.
Danish riot police push back protestors outside the venue of the U.N. Climate Conference in Copenhagen on Dec. 16.
A demonstrator hit by pepper spray receives help outside the U.N. talks on Dec. 16. Hundreds of climate demonstrators marched to the summit venue to show their anger over the slow progress being made by nations towards a climate deal.
A police officer uses his baton on activists trying to get into the U.N. talks on Dec. 16.
An activist shouts at police as he and others try to get into the U.N. talks in Copenhagen on Dec. 16. More than 200 people were arrested when they overran the police barricade to the summit conference hall.
A Danish riot policeman clubs an activist who climbed on top of a police vehicle outside the U.N. talks on Dec. 16.
An officer wipes his eyes after police used pepper spray against protesters on Dec. 16.
World Wide Fund for Nature (WWF) activists plant hand-shaped signs with the words "Tackle climate change!" outside the foreign ministry in Berlin, Germany, on Dec. 16.
Several hundred government delegates and environment ministers from around the world attend a plenary session on Dec. 16. The success of the U.N. climate conference is hanging in the balance as China and the U.S. deadlocked over whether Beijing will allow the world to check its books and verify promised cuts in greenhouse gas emissions.
Greepeace activists scale Australia's Sydney Opera House on Dec. 15 to make a climate statement urging nations to reach a treaty agreement. The activists were later arrested and charged with trespassing.
In Copenhagen, Denmark, climate activists have held daily rallies, including this one on Dec. 15. Copenhagen is the host city for the U.N. Climate Change Conference.
Riot police clash with climate activists in Copenhagen on Dec. 14. Between Dec. 12 and 14, police arrested nearly 1,300 activists.
Visitors to the National Mall in Washington, D.C., on Dec. 14 check out a mock ark meant to symbolize the lack of a backup plan if nations fail to agree to a climate treaty. One consequence of runaway warming would be rising seas and widespread flooding.
Several hundred protesters march during a climate protest in Copenhagen on Dec. 14.
Climate activists shout slogans during a march in Copenhagen on Dec. 14.
Former U.S. Vice President Al Gore speaks at a presentation Dec. 14 on melting Arctic ice at the U.N. Climate Change Conference in Copenhagen.
A member of Greenpeace demonstrates during a 'Climate No Border' protest in Copenhagen on Dec. 14. The activist is dressed as 'Death', one of the Four Horsemen of the Apocalypse.
People get ready before the start of a 'Climate No Borders' march together with several hundred protesters in Copenhagen.
Activists dressed as polar bears stage a protest at the U.N. Climate Summit in Copenhagen.
A protester looks out from inside a police vehicle following her arrest in Copenhagen on Sunday, Dec. 13. Ministers from 48 countries met behind closed doors amid fresh protests a day after police arrested nearly 1,000 demonstrators.
Archbishop Desmond Tutu gestures while speaking on stage during a "Time for Climate Justice" public event at Radhuspladsen in Copenhagen.
With emissions from a local factory behind it, a take-off on the Statue of Liberty that was erected by climate activists stands tall on Dec. 12, near the U.N. climate talks in Copenhagen, Denmark.
Climate activists taking part in a mass rally in Copenhagen on Dec. 12 hug a police officer standing guard.
Police in Copenhagen on Dec. 12 arrest some of the tens of thousands who marched downtown.
More than 600 people were detained as night fell in Copenhagen on Dec. 12.
A large globe featuring an interactive display sits in a central square in Copenhagen on Dec. 10.
In New Delhi, India, activists on Dec. 10 prepare to release sky lanterns to express their hopes for the climate conference.
A demonstrator taunts Danish riot police during a protest in Copenhagen on Dec. 11.
This ice sculpture of a polar bear set up in Copenhagen had nearly melted by Dec. 10.
This coal-fired power plant in Macedonia, seen on Dec. 10 as pigs feed on a nearby trash dump, is one of thousands around the world that emit large quantities of carbon dioxide.
Delegates gather on Dec. 10 before a plenary session at the 12-day U.N. climate summit in Copenhagen.
Activists dressed as aliens on Dec. 10 roam the halls where the U.N. climate summit is being held.
A woman walks past one of the dozens of exhibits at the climate summit on Dec. 10.
Thick smoke from a coal-fired oven fills the air in this neighborhood of Calcutta, India, on Dec. 9. Coal burning is a key source of manmade carbon dioxide emissions.
Climate activists throw lifesize inflatable dolls into the reflecting pool on the National Mall in Washington, D.C., on Dec. 9. Wearing t-shirts that say "CO2 Kills," the dolls are supposed to represent people who die from climate-related illness.
This balloon with a message sits near Copenhagen’s City Hall on Dec. 9.
Iceberg B17B, top left, floats in the Ross Sea near Antarctica after it broke off from the Ross Ice Shelf nearly 10 years ago. The monster iceberg, at 12 miles long and 5 miles wide nearly twice the size of Hong Kong, has been slowly drifting toward Australia in what scientists call a once-in-a-century event. It is now about 1,100 miles southwest of Australia. Accelerated glacial and ice shelf melt and collapses have been tied to global warming.
Lisa Jackson, the head of the U.S. Environmental Protection Agency, speaks at a news conference at the U.N. Climate Change Conference 2009 in Copenhagen on Dec. 9.
Climate change conference participants walk in front of a display of pictures on Dec. 9 in the Bella Center in Copenhagen, the venue of the 12-day meeting. Negotiators at the U.N.-organized marathon sought to calm emotions after developing countries blasted an early draft proposal that they said favored rich carbon emitters and sidelined the poor.
A man walks through heaps of ash outside a thermal power plant in the village of Doburjian in the northern Indian state of Punjab on Dec. 9. A 20 percent cut in greenhouse gases by rich nations would be a "pretty good" result for a U.N. climate summit, even though it falls short of developing nations' hopes, the head of the U.N. climate panel said during the meeting’s opening days.
Members of environmental activist group Greenpeace unfurl a banner from Rome's Colosseum on Dec. 9.
Emissions-producing diesel trucks and cars pass non-polluting windmills that stand along the I-10 freeway near Banning, Calif., on Dec. 8. Sustained global warming shows no sign of letting up, according to a new analysis by the World Meteorological Organization and made public at the climate talks in Copenhagen. Although global temperature fluctuates from year to year, overall the decade of the 2000s is likely the warmest in the last 150 years covered by the report. This decade is warmer than the 1990s which were warmer than the 1980s, and so on. The conclusions are in line with independent analysis by the National Climatic Data Center and NASA.
Delegates answer journalists' questions in front of the Bella Center in Copenhagen on the second day of the U.N. climate conference on Dec. 8. Talks hit turbulence on their second day, as developing countries, green groups and activists attacked an early draft of a compromise deal proposed by Denmark, the conference chair. The leaked document – dated Nov. 27 – was criticized as a backroom deal that favored rich countries on the key issues of emissions curbs and financing.
An activist outside the climate summit in Copenhagen on Dec. 8 makes a point about Europe not retreating from its aggressive targets for CO2 emissions reductions.
Mankind's reliance on fossil fuels, including these commuters in Taipei, Taiwan, on Dec. 7, is tied to the sharp increase in CO2 since the start of the industrial age.
Global actions to lobby for curbing greenhouse gas emissions include this rally by children, some dressed as trees, in Sidon, Lebanon, on Dec. 8.
This globe is part of the "Cool Globes" art installation on display in Copenhagen during the climate talks.
This furnace is part of a steel plant in Kazakhstan. The 1960s-era factory is Central Asia's biggest steel producer -- and one of its biggest emitters of CO2 and other greenhouse gases.
Commuters walk beneath a "Hopenhagen" banner in Copenhagen on Dec. 7. The climate summit is not expected to live up to original expecations of a global climate treaty with mandatory emissions reductions. That is now being talked about as a 2010 goal.
In London, England, activists camped out in Trafalgar Square over the weekend of Dec. 5 after taking part in a mass march through the city.
Power stations like this one in Hadera, Israel, have been a part of economc development but they are also key sources of CO2.
People watch an illuminated "CO2" cube in the water of St. Jorgens Lake in Copenhagen on Dec. 7. The cube represents the amount of carbon dioxide produced by an average person in one month.
Workers cut down trees as part of a road extension project in the southern Indian city of Chennai on Dec. 7. Officials at the climate talks in Copenhagen warned of the dangers of desertification and rising seas.
Sculptures are illuminated as they stand in water outside the climate conference in Copenhagen on Dec. 7.
Demonstrators block the entrance of Chevron Corp. in San Ramon, Calif., on Dec. 7 to coincide with the climate talks.
Journalists at work Dec. 7 at the climate conference in Copenhagen. Some 100 world leaders are expected to gather at the historic meeting on Dec. 18.
The U.N.'s top climate official, Yvo de Boer, left, and John Ash, chairman of a key summit committee, listen to a reporter's question at a press conference in Copenhagen on Dec. 6. De Boer held out hope for concrete action to curb emissions, but few expect a new treaty to replace the existing 1997 Kyoto pact.
Garbage is scattered across a ship repair yard in Mumbai, India, on Dec. 3. Rising seas is one issue before the climate conference in Copenhagen.
A cyclist stops to look at one of the "Cool Globes" in Copenhagen on Dec. 7.