Delegates to a climate conference in Stockholm said on Friday that a long-awaited report on global warming had been cleared line-by-line by the Intergovernmental Panel on Climate Change (IPCC) after overnight talks. The guide, intended for international decision-makers as a main reference document, concludes that is it "extremely likely" that humans caused more than half the warming observed over the past 60 years.
"Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased," said Qin Dahe, co-chair of the group that wrote the report.
It is the first of four reports about impacts and remedies for global warming entitled "Physical Science Basis." The full 2,000-page report to which 800 scientists contributed is due out on Monday. A 30-page summary of the report was released Friday.
In the report, scientists raised the probability that most global warming is man-made to 95 percent, up from 90 percent in a contentious IPCC report in 2007, which included an exaggeration on the melting rate of Himalayan glaciers.
As expected, the IPCC raised its projections of the rise in sea levels to 10-32 inches (26-82 centimeters) by the end of the century. The 2007 report predicted a rise of 7-23 inches.
Delegates warned that a recent slowdown in warming is unlikely to last, with more heat waves, droughts and floods, unless urgent action is taken to cut greenhouse gas emissions from burning fossil fuels.
Already, almost 200 governments have agreed in principle to limit global warming to a maximum rise of 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times and to work out a UN deal to limit their emissions accordingly by the end of 2015.
Temperatures have already risen about 0.8 Celsius and many leading scientists have said the 2-degree target is slipping out of reach.
In May, the UN's new climate chief Christiana Figueres said the world has entered a "new danger zone" with levels of Earth-warming carbon dioxide in the atmosphere by breaching the CO2 threshold of 400 parts per million (ppm) - a level never experienced by humankind.
From New York late on Thursday, Figueres said the latest IPCC report would be a wakeup call.
"It will tell us again that everything that we thought we knew on climate change has actually been underestimated," she told reporters at the UN General Assembly.
The IPCC is due to issue an overall synthesis report in late 2014 when a summit called by UN chief Ban Ki-moon is due. A UN summit in Copenhagen in 2009 failed to work out a global agreement.
Last year in Doha, Qatar, the European Union, Australia, Switzerland and eight other industrialized nations signed up for binding emission cuts until 2020 under an extension of a previous framework, the Kyoto Protocol. Together, however, these countries represent only 15 percent of global emissions.
The United States, China and India, which are the world's biggest emitters of CO2, have no binding targets.
US Secretary of State John Kerry called the report "yet another wakeup call."
"Those who deny the science or choose excuses over action are playing with fire," he said adding that the US would work with its allied on "ambitious actions to reduce emissions, transform our energy economy, and help the most vulnerable cope with the effects of climate change."
ipj/hc (Reuters, AP, AFP)