Notice! Care2 will go offline for site maintenance July 28 at 9pm PST. Thanks
START A PETITION 25,136,189 members: the world's largest community for good
START A PETITION
x
Jan 29, 2006

Warming debate shifts to ‘tipping point’

Some scientists worry it’s too late to reverse climate change

By Juliet Eilperin
The Washington Post
Updated: 11:31 p.m. ET Jan. 28, 2006
Now that most scientists agree human activity is causing Earth to warm, the central debate has shifted to whether climate change is progressing so rapidly that, within decades, humans may be helpless to slow or reverse the trend.


This "tipping point" scenario has begun to consume many prominent researchers in the United States and abroad, because the answer could determine how drastically countries need to reduce their greenhouse gas emissions in the coming years. While scientists remain uncertain when such a point might occur, many say it is urgent that policymakers cut global carbon dioxide emissions in half over the next 50 years or risk the triggering of changes that would be irreversible.


There are three specific events that these scientists describe as especially worrisome and potentially imminent, although the time frames are a matter of dispute: widespread coral bleaching that could damage the world's fisheries within three decades; dramatic sea level rise by the end of the century that would take tens of thousands of years to reverse; and, within 200 years, a shutdown of the ocean current that moderates temperatures in northern Europe.


‘We've got to do something’

The debate has been intensifying because Earth is warming much faster than some researchers had predicted. James E. Hansen, who directs NASA's Goddard Institute of Space Studies, last week confirmed that 2005 was the warmest year on record, surpassing 1998. Earth's average temperature has risen nearly 1 degree Fahrenheit over the past 30 years, he noted, and another increase of about 4 degrees over the next century would "imply changes that constitute practically a different planet."

"It's not something you can adapt to," Hansen said in an interview. "We can't let it go on another 10 years like this. We've got to do something."

Princeton University geosciences and international affairs professor Michael Oppenheimer, who also advises the advocacy group Environmental Defense, said one of the greatest dangers lies in the disintegration of the Greenland or West Antarctic ice sheets, which together hold about 20 percent of the fresh water on the planet. If either of the two sheets disintegrates, sea level could rise nearly 20 feet in the course of a couple of centuries, swamping the southern third of Florida and Manhattan up to the middle of Greenwich Village.


While both the Greenland and the Antarctic ice sheets as a whole are gaining some mass in their cold interiors because of increasing snowfall, they are losing ice along their peripheries. That indicates that scientists may have underestimated the rate of disintegration they face in the future, Oppenheimer said. Greenland's current net ice loss is equivalent to an annual 0.008 inch sea level rise.

The effects of the collapse of either ice sheet would be "huge," Oppenheimer said. "Once you lost one of these ice sheets, there's really no putting it back for thousands of years, if ever."


Small shift may key big changes

The report concludes that a temperature rise of just 1.8 degrees Fahrenheit "is likely to lead to extensive coral bleaching," destroying critical fish nurseries in the Caribbean and Southeast Asia. Too-warm sea temperatures stress corals, causing them to expel symbiotic micro-algae that live in their tissues and provide them with food, and thus making the reefs appear bleached. Bleaching that lasts longer than a week can kill corals. This fall there was widespread bleaching from Texas to Trinidad that killed broad swaths of corals, in part because ocean temperatures were 2 degrees Fahrenheit above average monthly maximums.


Many scientists are also worried about a possible collapse of the Atlantic thermohaline circulation, a current that brings warm surface water to northern Europe and returns cold, deep-ocean water south. Hans Joachim Schellnhuber, who directs Germany's Potsdam Institute for Climate Impact Research, has run multiple computer models to determine when climate change could disrupt this "conveyor belt," which, according to one study, is already slower than it was 30 years ago. According to these simulations, there is a 50 percent chance the current will collapse within 200 years.


Some scientists, including President Bush's chief science adviser, John H. Marburger III, emphasize there is still much uncertainty about when abrupt global warming might occur.

"There's no agreement on what it is that constitutes a dangerous climate change," said Marburger, adding that the U.S. government spends $2 billion a year on researching this and other climate change questions. "We know things like this are possible, but we don't have enough information to quantify the level of risk."

Visibility: Everyone
Tags: ,
Posted: Jan 29, 2006 12:14pm

 

 
 
Content and comments expressed here are the opinions of Care2 users and not necessarily that of Care2.com or its affiliates.

Author

Jenn Castori
, 3
Citrus Heights, CA, USA
Shares by Type:
All (1) | Blog (1)
Jenn's Tags:
global, warming
SHARES FROM JENN'S NETWORK
Feb
7
(0 comments  |  discussions )
http://www.thepetitionsit e.com/688/328/809/reviewl -obamas-executive-orders- for-constitutionality/Thi s a call for Congress to review and put an end to the Executive Orders made by Obama that allow us to be killed, Jailed, and detained forever, without ...
(0 comments  |  discussions )
The Susan B Kohmen foundation was caught misappropriating funds. Google it for proof. Also, mammograms cause cancer and the folks pushing them on us turn out to own stock in the machines themselves. Please search herbal remedies and cure yourself natu...
Sep
13
(0 comments  |  discussions )
(NaturalNews) The CDC has released a new zombie apocalypse preparedness campaign, and at one level, it almost begins to be useful. The \\\"Preparedness 101 Zombie Apocalypse\\\" novella is viewable online, connecting with the public through a pop culture ...
(0 comments  |  discussions )
(NaturalNews) It has been more than 50 years now since German drug giant Grunenthal unleashed for medical use the infamous horror drug known as thalidomide in 1957. The controversial morning sickness medication was quickly withdrawn worldwide in 1961 ...
(1 comments  |  discussions )
(NaturalNews) Genetically engineered wheat contains an enzyme suppressor that, when consumed by humans, could cause permanent liver failure (and death). That\\\'s the warning issued today by molecular biologist Jack Heinemann of the University of Canter...
(0 comments  |  discussions )
(NaturalNews) A growing number of Americans are already outraged over the government\\\'s use of high-powered, ultra-revealing and potentially dangerous backscatter x-ray machines at a growing number of the nation\\\'s airports, and as bad as that problem...
Sep
11
(1 comments  |  discussions )
\\nA Sheep No More\\r\\n7 \\\"Secret\\\" Ways We Are Being PoisonedThe objectivism of the scientific method seems to have been hijacked by corporations who often pay for scientists to support their products, as well as politicians who move through the revolv...
(0 comments  |  discussions )
\\r\\nA Sheep No More\\r\\nConstitutionali sts Labeled as Terrorists for Speaking Out Against the GovernmentSusanne Posel - Occupy CorporatismIn August, Brian Loftus, commercial fisherman and member of Oathkeepers, was harassed by local police for purchasi...
(0 comments  |  discussions )
(NaturalNews) A doctor at the Walter Reed Army Institute of Research (WRAIR) in Silver Spring, Maryland, the same locale where the U.S. Food and Drug Administration (FDA) coordinates its own tyrannous operations, has been awarded a $5 million grant to...
(0 comments  |  0 discussions )
(NaturalNews) Like Chicken Little running around screaming, \\\"the sky is falling,\\\" too many mainstream media and doctors have issued dire warnings about deadly bacteria that are no longer susceptible to antibiotics, leaving people virtually helpless ...