SPECIAL FEATURES:
Email
Greenhouse gases soared, but Asia's pollution cooled planet
World temperatures did not rise from 1998 to 2008 because pollution, specifically sulfur emissions from Asia, had a cooling effect.
Tue, Jul 05 2011 at 4:18 AM
Related Topics:
POLLUTION: Sulfur allows water drops or aerosols to form, creating hazy clouds that reflect sunlight back into space. (Photo: ZUMA Press)
LONDON - Smoke belching from Asia's rapidly growing economies is largely responsible for a halt in global warming in the decade after 1998 because of sulfur's cooling effect, even though greenhouse gas emissions soared, a U.S. study said on Monday.
The paper raised the prospect of more rapid, pent-up climate change when emerging economies eventually crack down on pollution.
World temperatures did not rise from 1998 to 2008, while manmade emissions of carbon dioxide from burning fossil fuel grew by nearly a third, various data show.
The researchers from Boston and Harvard Universities and Finland's University of Turku said pollution, and specifically sulfur emissions, from coal-fueled growth in Asia was responsible for the cooling effect.
Sulfur allows water drops or aerosols to form, creating hazy clouds which reflect sunlight back into space.
"Anthropogenic activities that warm and cool the planet largely cancel after 1998, which allows natural variables to play a more significant role," the paper said.
Natural cooling effects included a declining solar cycle after 2002, meaning the sun's output fell.
The study said that the halt in warming had fueled doubts about anthropogenic climate change, where scientists say manmade greenhouse gas emissions are heating the Earth.
"It has been unclear why global surface temperatures did not rise between 1998 and 2008," said the study published in the Proceedings of the National Academy of Sciences of the United States.
A peak in temperatures in 1998 coincided with a strong El Nino weather event, a natural shift which brings warm waters to the surface of the Pacific Ocean every few years.
Subsequent years have still included nine of the top 10 hottest years on record, while the U.N. World Meteorological Organization said 2010 was tied for the record.
A U.N. panel of climate scientists said in 2007 that it was 90 percent certain that humankind was causing global warming.
COAL
Sulfur aerosols may remain in the atmosphere for several years, meaning their cooling effect will gradually abate once smokestack industries clean up.
The study echoed a similar explanation for reduced warming between the 1940s and 1970s, blamed on sulfur emissions before Western economies cleaned up largely to combat acid rain.
"The post 1970 period of warming, which constitutes a significant portion of the increase in global surface temperature since the mid 20th century, is driven by efforts to reduce air pollution," it said.
Sulfur emissions are linked to coal consumption which in China grew more than 100 percent in the decade to 2008, or nearly three times the rate of the previous 10 years, according to data from the energy firm BP.
Other climate scientists broadly supported Monday's study, stressing that over longer time periods rising greenhouse gas emissions would over-ride cooling factors.
"Long term warming will continue unless emissions are reduced," said Peter Stott, head of climate monitoring at Britain's Met Office.
Copyright 2011 Reuters Environmental Online Report
You might also like:
Sign in with one of these accounts to add your comment.
EDITORS' PICKS
Advertisement
TODAY'S MOST POPULAR ON
- 15 famous people who mysteriously disappeared
- Spanish town sends dog poop back to irresponsible pet owners
- Too beautiful to be real? 16 surreal landscapes found on Earth
- 7 surprising things Pope Francis has done in his first 100 days
- Yurts: Everything you ever wanted to know but were afraid to ask
- 5 mind-bending facts about dreams
- 10 false facts most people think are true
- Henry Cavill's 'Man of Steel' workout and diet
- Henry Cavill's 'Man of Steel' workout video
- 13 natural remedies for the ant invasion
NEWSLETTER
Advertisement
Just another lame excuse to go right on growing the economy to sell to the growing human population. But the biosphere cannot survive the massive and growing garbage, sludge and junk dumped everywhere, but mostly in the ocean To survive, we need to live in balance by safely recycling 100% of our trash and waste, and peacefully reduce our human population with family planning education.