TBO.com - TBO is Tampa Bay Online

Rising Seas, Suffering Forecast As Earth Warms

ADVERTISEMENT

By DOUG STRUCK, The Washington Post

Published: November 18, 2007

The world will have to end its growth of carbon emissions within seven years and become mostly free of carbon-emitting technologies in about four decades to avoid killing as many as a quarter of the planet's species from global warming, according to top United Nations scientists.

The stark choices laid out Saturday by the agency's Intergovernmental Panel on Climate Change describe the daunting task if the world is to avoid the consequences of a planet heated up by more than 3.6 degrees Fahrenheit since 2000.

The panel, which distilled research from about 2,500 scientists, avoided moral conclusions about how much global warming is too much.

"The scientists now have done their work. I call on political leaders to do theirs," U.N. Secretary-General Ban Ki-moon said upon formally receiving the report Saturday in Valencia, Spain.

The tables laid out in the report describe mounting grim consequences for each degree of atmospheric heating of the planet and the difficult steps that must be taken to avoid even the worst of those consequences.

To avoid heating the globe by the minimum possible, an average of 3.6 degrees Fahrenheit, the world's spiraling growth in greenhouse gas emissions must end no later than 2015, the report said, and must start to drop quickly after that peak. By 2050, carbon dioxide and other atmospheric polluting gases must be reduced by 50 percent to 85 percent, according to the estimates.

That would require a drastic reworking of industrial processes, transportation, agricultural practices and even the buildings people live in, according to the report's calculations.

"We may have already overshot that target," said David Karoly, one member of the core team that wrote the report. Current emissions already are nearing the limit required in 2015 to limit the warming to 3.6 degrees Fahrenheit, he said.

Even at that threshold, the seas will continue to swell for centuries from thermal expansion and melt water from ice caps and glaciers, the oceans will turn more acidic, most coral reefs will become lifeless expanses, floods and storms will increase, and millions of people will be short of the water they need, the report said.

If the world misses that target, however, and does not stabilize carbon dioxide emissions until 2030, for example, the planet's temperature will increase by as much as 6.3 degrees Fahrenheit above 2000 temperatures, the report said.

That level of warming would result in widespread extinctions of species, a slowing of the global currents, decreased food production, loss of 30 percent of global wetlands, flooding for millions of people and higher deaths from heat waves.

Policymakers in Europe and other governments generally have regarded the 3.6-degree Fahrenheit rise as the maximum the world should tolerate. The Bush administration has resisted making such a judgment.

In a final speech to the delegates, Ban described how impressed he was on recent trips to the Amazon jungle and Antarctica, both of which would be severely threatened, he said, if mankind does not curb global warming.

"If the panel's most severe projection comes through, much of the Amazon rain forest will transform into savannah," he said. "These things are as frightening as science-fiction movies. But they are even more terrifying, because they are real."

TROUBLED CLIMATE

The following are some key findings in a report issued Saturday by the United Nations Intergovernmental Panel on Climate Change:

•Temperatures have risen 1.3 degrees Fahrenheit in the past 100 years. Eleven of the last 12 years are among the warmest since 1850. Sea levels have gone up by an average seven-hundredths of an inch per year since 1961.

•About 20 percent to 30 percent of all plant and animal species face risk of extinction if temperatures increase by 2.7 degrees Fahrenheit. If the thermometer rises 6.3 degrees Fahrenheit, 40 percent to 70 percent of species could disappear.

•Human activity is largely responsible for warming. Global emissions of greenhouse gases grew 70 percent from 1970 to 2004. The concentration of carbon dioxide in the atmosphere is far higher than the natural range over the past 650,000 years.

•Extreme weather conditions will be more common. Tropical storms will be more frequent and intense. Heat waves and rainstorms will raise the risk of wildfires and the spread of diseases. Elsewhere, drought will degrade cropland and spoil the quality of water sources. Rising sea levels will increase flooding and salination of fresh water, and threaten coastal cities.

•Even if greenhouse gases are stabilized, the Earth will keep warming and sea levels rising. More pollution could bring "abrupt and irreversible" changes, such as the loss of ice sheets in the poles, and a corresponding rise in sea levels by several yards.

The Associated Press

Share this:

Loading Comments...

Email Print

ADVERTISEMENT