Nov. 24, 2009— -- There's even less time for humanity to try to curb global warming than recently thought, according to a new in-depth scientific assessment by 26 scientists from eight countries.
Sea level rise, ocean acidification and the rapid melting of massive ice sheets are among the significantly increased effects of human-induced global warming assessed in the survey, which also examines the emissions of heat-trapping gases that are causing the climate change.
"Many indicators are currently tracking near or above the worst-case projections" made three years ago by the world's scientists, the new Copenhagen Diagnosis said.
The scientists also calculate that the world's emissions of heat-trapping gases must peak in less than 10 years and then dive quickly to nearly zero, if warming of more than another 2 degrees Fahrenheit above the current annual global temperature is to be prevented after 2050.
Any warming of more than 2 degrees F above current temperatures has been generally agreed among governments around the world to be "dangerous," though what "dangerous" means is still debated.
This is the first comprehensive update of leading peer-reviewed climate science in the three years since the last report of the intentionally thorough and slow-paced Intergovernmental Panel on Climate Change was finalized.
That report is now widely recognized to be out of date in important ways.
This is because over the past three years, hundreds of new scientific field accounts of global warming's impacts, as well as improved peer-reviewed analyses of global warming itself in both the deep past and the very near future, have depicted earth's atmosphere as far more "sensitive" to the invisible CO2, methane and other human-sourced greenhouse gases than had been hoped.
"Mother nature puts a limit on how long you can dither and procrastinate," climatologist Richard Somerville, one of the study's authors, told ABC News.
"We found that several vulnerable elements in Earth's climate system -- like the Amazon and other big rain forests, like the great ice sheets that have so much sea level locked up in their ice -- could be pushed toward abrupt or irreversible change if we go on toward 2100 with our business-as-usual increase in emissions of greenhouse gases," he said.
Global Warming Report Out in Time for Copenhagen Summit
Because the next IPCC report is not due before 2013, there had been a growing concern among many of the world's climate scientists that an update of the latest solid data would be needed, he said, if negotiations by the 192 nations gathering at the Copenhagen climate summit, scheduled for Dec. 7-18, were to be based on reality.
By phone from his base at Scripps Institution of Oceanography in California, Somerville told ABC News that the 26 authors of the survey all donated their time and expertise.
"The money we needed for basic transportation to get us to and from our big global review session in Copenhagen in March and for basic communication expenses turned up from the Live Earth philanthropy," Somerville said.
Live Earth, founded by producer Kevin Wall, in partnership with former Vice President Al Gore, is a for-profit company that uses concerts, media and other events to encourage awareness worldwide about environmental issues.
"They've had no influence or involvement of any kind with the report itself," he said. "That is entirely under the control of the 26 authors from the eight countries, all widely respected -- and many of them are lead authors of IPCC studies. They're known quantities in the peer-reviewed science world."
Though this report is not "officially" from the IPCC, which makes no provisions for comprehensive mid-term reports halfway through its five- or six-year reporting cycle, Somerville said he and his fellow authors expect that it will be accepted by their peers in climate research around the world.
"This report is firmly based on more than 200 recent peer-reviewed papers clearly listed in the report," he said.
The authors said they were aiming not only at policy makers, but also at the general public.
Common misconceptions about global warming are dealt with in separate side-bar boxes, explaining why, for example, the human-induced warming has not slowed or paused, contrary to some recent headlines.
The authors also give a relatively reassuring assessment about the chances of an uncontrollable "runaway" global temperature rise in the near future.
Their findings include:
It could well be around three feet before the year 2100, says the report. Just a fraction of that increase in sea level could displace many millions of people and greatly increase vulnerability to storms.
A sea-level rise of 6 ½ feet is now considered by the scientists to be a reasonable "upper bound" of estimates -- a distinct possibility.
Global Warming Report: Ice Sheets, Glaciers Melting Faster Than Predicted
Scientists are at constant pains to point out that recent (or any) slight and brief emissions drops in a few countries cause no reduction of the greenhouse gas concentrations in the atmosphere that set the global temperature thermostat.
This is because CO2 emissions stay in the air, on average, for hundreds of years.
Somerville and other scientists say they frequently have to make sure people they talk to understand the difference between "emissions" -- the amount of additional heat-trapping gas humanity puts in the atmosphere per year, and "concentrations" -- the amount of those gases that has piled up in the atmosphere and goes on hanging there for a long time.
Concentrations, which are measured in parts per million, have been rising steadily since the beginning of the industrial age some two centuries ago.
By what appears to be a devilish coincidence, this same molecule that warms the atmosphere, CO2, happens, when combined with H20, to form carbonic acid.
Scientists report the sea is already 30 percent more acidic than it was at the start of the industrial age.
A wide range of studies and reports of damage to sea life as a result of this rise in acidity is now coming in from the world's marine biologists.
Relative Good News: 'No Strong Evidence' Overall Tipping Point
There is one piece of relatively good news from the scientists in this report, in regard to what it calls "much talk in the popular media" about the possibility of "runaway" climate change.
It says this would be what's sometimes called "a global tipping point," in which many amplifying feedbacks around the world produce a cumulative effect in which Earth enters a "change in state, carried by its own internal dynamics."
Many amplifying feedbacks are closely monitored by scientists, including thawing tundra and dying forest releasing massive amounts of heat-trapping CO2, and the way in which the growing amount of darkened land absorbs more of the sun's heat, thus further warming the ground and air.
Such a "change of state" could be uncontrollable, and possibly, some have worried, so fast that food supplies and human civilization in general would collapse.
Of this most frightening prospect, the report says clearly: "There is as yet no strong evidence that the Earth as a whole is near such a threshold. Instead 'amplified' climate change is a much better description of what we currently observe and project for the future."
In other words, though painful changes are apparently coming in the next few decades and before there is a chance of getting Earth's rising annual global temperature to level off, there is still time, according to the latest science, to avoid the very worst.
At least, it says, "there is as yet no strong evidence" that such an overall threshold "is near."