Climate - Oct 11
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Study: Rise in humidity caused by humans
Seth Borenstein, Associated Press
WASHINGTON - With global warming, the world isn't just getting hotter - it's getting stickier, due to humidity. And people are to blame, according to a study based on computer models published Thursday.
The amount of moisture in the air near Earth's surface rose 2.2 percent in less than three decades, the researchers report in a study appearing in the journal Nature.
"This humidity change is an important contribution to heat stress in humans as a result of global warming," said Nathan Gillett of the University of East Anglia in the United Kingdom, a co-author of the study.
(10 October 2007)
Zero emissions needed to avert 'dangerous' warming
Catherine Brahic, New Scientist
Only the total elimination of industrial emissions will succeed in limiting climate change to a 2°C rise in temperatures, according to computer analysis of climate change. Anything above this target has been identified as "dangerous" by some scientists, and the limit has been adopted by many policymakers.
The researchers say their study highlights the shortcomings of governmental plans to limit climate change.
A warming of 2°C above pre-industrial temperatures is frequently cited as the limit beyond which the world will face "dangerous" climate change. Beyond this level, analysis suggests the continents will cease to absorb more carbon dioxide than they produce. As the tundra and other regions of permafrost thaw, they will spew more gas into the atmosphere, adding to the warming effect of human emissions.
The end result will be dramatic ecological changes, including widespread coastal flooding, reduced food production, and widespread species extinction.
In January 2007, the European Commission issued a communication stating that "the European Union's objective is to limit global average temperature increase to less than 2°C compared to pre-industrial levels".
Andrew Weaver and colleagues at the University of Victoria in Canada say this means going well beyond the reduction of industrial emissions discussed in international negotiations.
(11 October 2007)
Recommended by contributor Bill Henderson.
'Global-cooling' scare of the 1970s.
Tony Azios, The Christian Science Monitor
Global-warming skeptics: Is it only the news media who need to chill?
Some who discount humans' role in altering Earth's climate point to the 'global-cooling' scare of the 1970s.
In the 1970s, mainstream media outlets published stories about a coming age of "global cooling" and the climate disaster it would trigger. Headlines of the time proclaimed "The Cooling World" (Newsweek, 1975), "Scientists Ask Why World Climate Is Changing: Major Cooling May Be Ahead" (The New York Times, 1975), and "Earth Seems to be Cooling Off Again" (The Christian Science Monitor, 1974).
Today, skeptics of global warming sometimes point to what they call the "global-cooling scare" of the 1970s as a reason to discount what they hear now. If the news media 30 years ago hyped "global cooling" and were wrong, skeptics say, doesn't it follow that "global warming" coverage might prove equally wrong?
But those who have looked closely at the two eras or have been part of the scientific community then and now say the comparison is unfair. William Connolley, a sort of self-appointed historian of the global-cooling theory, says that although global cooling was briefly but prominently covered in some speculative news articles, the idea never got much traction within the scientific community. New data and research over the decades has convinced the vast majority of scientists that global warming is real and under way.
(11 October 2007)
Atlanta's Lake Lanier has three months of water storage left
Stacy Shelton, Atlanta Journal-Constitution
Lake Sidney Lanier, metro Atlanta's main source of water, has about three months of storage left, according to state and federal officials.
That's three months before there's not enough water for more than 3 million metro Atlantans to take showers, flush their toilets and cook. Three months before there's not enough water in parts of the Chattahoochee River for power plants to make the steam necessary to generate electricity. Three months before part of the river runs dry.
"We've never experienced this situation before," state Environmental Protection Division Director Carol Couch said of the record-breaking drought and fast-falling lake.
(11 October 2007)
The Big Melt
Lessons from the Carbon Summer of 2007 (PDF)
David Spratt, CarbonEquity
- Climate change impacts are happening at lower temperature increases and more quickly than projected.
- The Arctic's floating sea ice is headed towards rapid summer disintegration as early as 2013, a century ahead of the International Panel on Climate Change (IPCC) projections.
- The rapid loss of Arctic sea ice will speed up the disintegration of the Greenland ice sheet, and a rise in sea levels by even as much as 5 metres by the turn of this century is possible.
- The Antarctic ice shelf reacts far more sensitively to warming temperatures than previously believed.
- Long-term climate sensitivity (including "slow" feedbacks such as carbon cycle feedbacks which are starting to operate) may be double the IPCC standard.
- A doubling of climate sensitivity would mean we passed the widely accepted 2°C threshold of "dangerous anthropogenic interference" with the climate four decades ago, and would require us to find the means to engineer a rapid drawdown of current atmospheric greenhouse gas.
- Carbon dioxide (CO2) emissions are now growing more rapidly than "business-as-usual", the most pessimistic of the IPCC scenarios.
- Temperatures are now within ?1°C of the maximum temperature of the past million years.
- We must choose targets and take actions that can actually solve the problem in a timely manner.
- The object of policy-relevant advice must be to avoid unacceptable outcomes and seemingly extreme or alarming possibilities, not to determine just the apparently most likely outcome.
- The 2°C warming cap is a political compromise; with the speed of change now in the climate system and the positive feedbacks that 2°C will trigger, it looms for perhaps billions of people and millions of species as a death sentence.
- To allow the reestablishment and long-term security of the Arctic summer sea ice it is likely to be necessary to bring global warming back to a level at or below 0.5°C (a long-term precautionary warming cap) and for the level of atmospheric greenhouse gases at equilibrium to be brought down to or below a long-term precautionary cap of 320 ppm CO2e.
- The IPCC suffers from a scientific reticence and in many key areas the IPCC process has been so deficient as to be an unreliable and dangerously misleading basis for policy-making.
The Carbon Equity Project has a lot of good information, though it lacks an "About Us" page. The website does list its principles. A talk/slides by author Spratt at a 2007 conference in Melbounde is available here.
Recommended by Gail Tverberg at The Oil Drum who writes:
"... a truly worry-some report. Besides the arctic melt, it talks about the possibility of Greenland melt and Antarctic melt. The graph shown above [below] is amazing."
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