cheers

Good news that an asteroid didn't cause the massive extinctions, what with one bearing down on us in the near future.

Global Warming Nears Critical Point of No Return, Group Says
By Ed Johnson
Associated Press
posted: 24 January 2005
05:32 pm ET

LONDON (AP) -- Global warming is approaching the critical point of no return, after which widespread drought, crop failure and rising sea-levels would be irreversible, an international climate change task force warned Monday.

The report, "Meeting the Climate Challenge,'' called on the G-8 leading industrial nations to cut carbon emissions, double their research spending on green technology and work with India and China to build on the Kyoto Protocol.

"An ecological time-bomb is ticking away,'' said Stephen Byers, who co-chaired the task force with U.S. Republican Senator Olympia Snowe, and is a close confidant of British Prime Minister Tony Blair. "World leaders need to recognize that climate change is the single most important long term issue that the planet faces.''

The independent report, by the Institute for Public Policy Research in Britain, the Center for American Progress in the United States and The Australia Institute, is timed to coincide with Blair's commitment to advance international climate change policy during Britain's G-8 presidency.

Byers said it was vital Blair secured U.S. cooperation in tackling climate change. U.S. President George W. Bush has rejected the Kyoto accord, arguing that the carbon emission cuts it demands would damage the U.S. economy.

"What we have got to do then is get the Americans as part of the G-8 to engage in international concerted effort to tackle global warming,'' said Byers. "If they refuse to do that then other countries will be reluctant to take any steps.''

According to the report, urgent action is needed to stop the global average temperature rising by 2 degrees Celsius above the level in 1750 -- the approximate start of the Industrial Revolution when mankind first started significantly polluting the atmosphere with carbon dioxide.

Beyond a 2 degrees rise, "the risks to human societies and ecosystems grow significantly'' the report said, adding there would be a risk of "abrupt, accelerated, or runaway climate change.''

It warned of "climatic tipping points'' such as the Greenland and West Antarctic ice sheets melting and the Gulf Stream shutting down.

No accurate temperature readings were available for 1750, the report said, but since 1860, global average temperature had risen by 0.8 percent to 15 degrees Celsius.

The two degrees rise could be avoided by keeping the concentration of carbon dioxide in the atmosphere below 400 parts per million (ppm). Current concentrations of 379 ppm "are likely to rise above 400 ppm in coming decades and could rise far higher under a business-as-usual scenario,'' the report warned.

The task force urges all G-8 countries to agree to generate a quarter of their electricity from renewable sources by 2025 and to shift agricultural subsidies from food crops to biofuels.

The report recommends wider international use of emission trading schemes which are already in use in the European Union, under which unused carbon dioxide quotas are sold. The profit motive is expected to drive investment in new technology to cut emissions further.

The task force of senior politicians, scientists and business figures was established in March 2004. Its chief scientific adviser is Dr. Rajendra K. Pachauri, chairman of the U.N.'s Intergovernmental Panel on Climate Change.

The British government welcomed the report, which mirrors many of the suggestions already floated by Blair in the build up to Britain's G-8 presidency.

Blair has acknowledged the importance of U.S. cooperation, but conceded Washington is unlikely to sign up to Kyoto. Instead he is pursuing international commitment to developing new environmentally friendly technology.

Tendrils of condensation that mark the paths of high-flying jets sometimes form a loose lacework of man-made clouds in the upper atmosphere. The extra blanket of atmospheric insulation from these spreading contrails, as they are called, could accelerate global warming, studies have shown.

Now a group of researchers says something should be done. Their proposal would lengthen the typical airline flight.

High-altitude cirrus clouds, both natural and jet-induced, are unlike thicker low-altitude clouds, which block sunlight from reaching the surface. The thinner cirrus, which float in the sky at 20,000 feet or higher, act like a see-through blanket – letting sunlight pass in, while trapping reflected heat.

A rise in contrail formation -- and therefore blanketing -- is expected in the future, because air travel is growing at 3 percent to 5 percent a year, and cargo transportation by air is increasing by 7 percent a year.

In a recent investigation of air traffic trends, researchers at the Imperial College London came up with guidelines for minimizing the climate impact from contrails. They propose setting ceilings on the altitude that jets can fly: 31,000 feet in the summer and 24,000 feet in the winter.

On long flights, most jets cruise at about 35,000 feet. This conserves fuel, since there is less drag through the thinner, high-altitude air. But the environmental benefit of better fuel efficiency may be offset by the warming aspect of contrail formation.

"We'd like this research to inform government policies, not just in the UK but throughout the [European Union] and the rest of the world so that decision makers can take all the environmental issues into account and do the right thing," said Robert Noland, leader on the investigation.

Contrail effects are not now included in governmental assessments of the impact from air travel.

Heat-trapping web

Condensation trails -- contrails -- form when hot, humid air coming out of a jet engine mixes with the colder surrounding air of the atmosphere. Water in the air condenses around particles in the exhaust.

Depending on how much moisture is in the air, contrails can be long-lived, spreading out to look more like the wispy cirrus clouds made by Nature.

Because the atmosphere becomes generally colder at higher altitudes, it is easier for contrails to form behind higher-flying aircraft. Therefore, imposing a maximum altitude for commercial flights could reduce contrail formation.

The impact from jet exhaust became evident in the days after the Sept. 11, 2001, terrorist attacks, when most air traffic in the United States was halted.

During the stoppage, astronaut Frank Culbertson, on the International Space Station, told flight controllers, "Normally when we go over the U.S., the sky is like a spider web of contrails. And now the sky is just about completely empty."

During this period, a study found that daily temperatures became one degree Celsius (1.8 degrees Fahrenheit) lower when the skies were clear of contrails.

A more recent report from NASA documented a 1 percent per decade increase in cirrus cloud cover over the United States, presumably due to increased air travel. The researchers claimed that this extra cloudiness could account for a warming trend of half a degree Fahrenheit per decade in the years between 1975 and 1994.

Policy changes

Requiring planes to cruise at lower altitudes would cause longer flights and require more fuel. But in weighing the two possibilities, Noland and his collaborators conclude that a rise in the number of contrails would be worse for the environment.

"There is little more that aircraft designers can do to increase engine fuel efficiency at high altitude," Noland said, "but designing new aircraft that can be as fuel efficient flying at 20,000 feet, as today's aircraft are at 35,000 feet, would help eliminate contrails."

Besides altitude, the researchers discovered that weather conditions affect the likelihood of contrails. In fact, there are days when the atmospheric conditions make it almost impossible to avoid forming the spindly clouds. The ultimate strategy might entail day-to-day decisions to avoid air masses that are susceptible to contrail formation. Moreover, simple software could be developed to warn a pilot when his or her plane is leaving a "jetprint" in the sky.

Instead of making them fly lower, I say we just restrict all flights to October through March and require them to fly over North Dakota, regardless of where they are going.

I think Kofi is waiting for a little palm grease before freeing up the UN's global warming credits. Lubricating the UN appears to have worked for Saddam, maybe governor Hoven can swing something for North Dakota as well, like free curling lessons, a lutefisk and lefse dinner, or an ice fishing vacation.