UN climate report offers stark warnings, hope

Climate Report Sets Deadline for Zero Carbon Emissions

COPENHAGEN, Denmark (AP) - Climate change is happening, it's almost entirely man's fault and limiting its impacts may require reducing greenhouse gas emissions to zero this century, the U.N.'s panel on climate science said Sunday.

The fourth and final volume of the Intergovernmental Panel on Climate Change's giant climate assessment didn't offer any surprises, nor was it expected to since it combined the findings of three earlier reports released in the past 13 months.

But it underlined the scope of the climate challenge in stark terms. Emissions, mainly from the burning of fossil fuels, may need to drop to zero by the end of this century for the world to have a decent chance of keeping the temperature rise below a level that many consider dangerous. Failure to do so, which could require deployment of technologies that suck greenhouse gases out of the atmosphere, could lock the world on a trajectory with "irreversible" impacts on people and the environment, the report said. Some impacts are already being observed, including rising sea levels, a warmer and more acidic ocean, melting glaciers and Arctic sea ice and more frequent and intense heat waves.

"Science has spoken. There is no ambiguity in their message. Leaders must act. Time is not on our side," U.N. Secretary-General Ban Ki-moon said at the report's launch in Copenhagen.

Amid its grim projections, the report also offered hope. The tools needed to set the world on a low-emissions path are there; it just has to break its addiction to the oil, coal and gas that power the global energy system while polluting the atmosphere with heat-trapping CO2, the chief greenhouse gas.

"We have the means to limit climate change," IPCC chairman Rajendra Pachauri said. "All we need is the will to change, which we trust will be motivated by knowledge and an understanding of the science of climate change."

The IPCC was set up in 1988 to assess global warming and its impacts. The report released Sunday caps its latest assessment, a mega-review of 30,000 climate change studies that establishes with 95-percent certainty that nearly all warming seen since the 1950s is man-made.

Today only a small minority of scientists challenge the mainstream conclusion that climate change is linked to human activity.

Sleep-deprived delegates approved the final documents Saturday afternoon after a weeklong line-by-line review in Copenhagen that underscored that the IPCC process is not just about science. The reports must be approved both by scientists and governments, which means political issues from U.N. climate negotiations, which are nearing a 2015 deadline for a global agreement, inevitably affect the outcome.

The rift between developed and developing countries in the U.N. talks opened up in Copenhagen over a box of text that discussed what levels of warming could be considered dangerous. After a protracted battle, the delegates couldn't agree on the wording, and the box was dropped from a key summary for policy-makers to the disappointment of some scientists.

"If the governments are going to expect the IPCC to do their job," said Princeton professor Michael Oppenheimer, a lead author of the IPCC's second report, they shouldn't "get caught up in fights that have nothing to do with the IPCC."

The omission of the box meant the word "dangerous" disappeared from the summary altogether. It appeared only twice in a longer underlying report compared to seven times in a draft produced before the Copenhagen session.

But the less loaded word "risk" was mentioned 65 times in the final 40-page summary.

"Rising rates and magnitudes of warming and other changes in the climate system, accompanied by ocean acidification, increase the risk of severe, pervasive, and in some cases irreversible detrimental impacts," the report said.

World governments in 2009 set a goal of keeping the temperature rise below 2 degrees C (3.6 F) compared to before the industrial revolution. Temperatures have gone up about 0.8 C (1.4 F) since the 19th century.

Meanwhile, emissions have risen so fast in recent years that the world has already used up two-thirds of its carbon budget, the maximum amount of CO2 that can be emitted to have a likely chance of avoiding 2 degrees of warming, the IPCC report said.

"This report makes it clear that if you are serious about the 2-degree goal ... there is nowhere to hide," said Alden Meyer of the Union of Concerned Scientists, an advocacy group. "You can't wait several decades to address this issue."

U.S. Secretary of State John Kerry called the report "another canary in the coal mine."

"The bottom line is that our planet is warming due to human actions, the damage is already visible, and the challenge requires ambitious, decisive and immediate action," Kerry said in a statement. "Those who choose to ignore or dispute the science so clearly laid out in this report do so at great risk for all of us and for our kids and grandkids."

Pointing to the solution, the IPCC said the costs associated with mitigation action such as shifting the energy system to solar and wind power and other renewable sources and improving energy efficiency would reduce economic growth only by 0.06 percent annually.

And Pachauri said that cost should be measured against the implications of doing nothing, putting "all species that live on this planet" at peril.

The report is meant as a scientific roadmap for the U.N. climate negotiations, which continue next month in Lima, Peru. That's the last major conference before a summit in Paris next year, where a global agreement on climate action is supposed to be adopted.

"Lima should be the place where we put the pieces together so we can move toward success" in Paris, said Peruvian Environment Minister Manuel Pulgar-Vidal.

The biggest hurdle is deciding who should do what, with rich countries calling on China and other major developing countries to take on ambitious targets, and developing countries saying the rich have a historical responsibility to lead the fight against warming and to help poorer nations cope with its impacts. The IPCC carefully avoided taking sides in that discussion, saying the risks of climate change "are generally greater for disadvantaged people and communities in countries at all levels of development."

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Climate Change March - New York - 9/21/2014
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UN climate report offers stark warnings, hope
Marchers make their way across Central Park South during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Musician Sting walks down 6th Avenue during the People's Climate March on September 21, 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Marchers come down 6th Ave during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Actor Leonardo DiCaprio walks down 6th Avenue during the People's Climate March on September 21, 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Children run underneath a large banner with demonstrators gathered for the People's Climate March in New York, U.S., on Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
Marchers come down 6th Ave during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Demonstrators hold signs on a street next to Central Park during the People's Climate March in New York, U.S., on Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators hold signs during the People's Climate March in New York, U.S., on Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
NEW YORK, NY - SEPTEMBER 21: Sting attends The People's Climate March on September 21, 2014 in New York City. (Photo by Rob Kim/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
Marchers come down 6th Ave during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
Actor Leonardo DiCaprio walks down 6th Avenue during the People's Climate March on September 21, 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Marchers come down 6th Ave during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
Marchers come down 6th Ave during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
A demonstrator holds a sign during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators hold signs during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators hold signs during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
A demonstrator holds a sign during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators hold signs during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
A demonstrator wears a flag as a cape during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators roll a model of the planet Earth down the street during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators hold signs during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
A demonstrator plays a guitar while others hold signs during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators march during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Demonstrators hold an Adbusters.org American flag during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
A demonstrator holds up a sign during the People's Climate March in New York, U.S., on Sunday, Sept. 21, 2014. The United Nations 2014 Climate Summit is scheduled for Sept. 23. Photographer: Timothy Fadek/Bloomberg via Getty Images
Marchers come down 6th Ave during the People's Climate March on September 21 2014, in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders . AFP PHOTO/Timothy A. Clary (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)
French Foreign Minister Laurent Fabius takes part in the 'People's Climate March' on September 21, 2014 in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders. AFP PHOTO/Don Emmert (Photo credit should read DON EMMERT/AFP/Getty Images)
United Nations Secretary-General Ban Ki-moon and his wife Yoo Soon-taek take part in the 'People's Climate March' on September 21, 2014 in New York. Activists mobilized in cities across the globe Sunday for marches against climate change, with one of the biggest planned for New York, where celebrities, political leaders and tens of thousands of people were expected. The march comes before the United Nations Secretary-General Ban Ki-moon convenes a climate change summit of 120 world leaders. AFP PHOTO/Don Emmert (Photo credit should read DON EMMERT/AFP/Getty Images)
NEW YORK, NY - SEPTEMBER 21: United Nations Secretary General Ban Ki-Moon participates in the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: (L-R) Primatologist Jane Goodall, Former U.S. Vice President and environmental activist Al Gore, New York City Mayor Bill deBlasio and United Nations Secretary General Ban Ki-Moon participates in the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, NY - SEPTEMBER 21: People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)
NEW YORK, UNITED STATES - SEPTEMBER 21: Illuminated UN headquarters is seen during a ceremony ahead of climate march at the UN headquarters in New York, United States on September 21, 2014. The Hollywood star was named United Nations Messenger of Peace on Climate Change. (Photo by Selcuk Acar/Anadolu Agency/Getty Images)
NEW YORK, UNITED STATES - SEPTEMBER 21: Illuminated UN headquarters is seen during a ceremony ahead of climate march at the UN headquarters in New York, United States on September 21, 2014. The Hollywood star was named United Nations Messenger of Peace on Climate Change. (Photo by Selcuk Acar/Anadolu Agency/Getty Images)
NEW YORK, UNITED STATES - SEPTEMBER 21: Illuminated UN headquarters is seen during a ceremony ahead of climate march at the UN headquarters in New York, United States on September 21, 2014. The Hollywood star was named United Nations Messenger of Peace on Climate Change. (Photo by Selcuk Acar/Anadolu Agency/Getty Images)
NEW YORK, UNITED STATES - SEPTEMBER 21: Illuminated UN headquarters is seen during a ceremony ahead of climate march at the UN headquarters in New York, United States on September 21, 2014. The Hollywood star was named United Nations Messenger of Peace on Climate Change. (Photo by Selcuk Acar/Anadolu Agency/Getty Images)
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