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Global Warming Worries the Scientific Community PDF Print E-mail
Saturday, 05 April 2008

By: Dr. Sultan Ahmad

Since the signing of Kyoto Protocol on 11 December, 1997; no significant action has yet been noticed by the world community to deal with the problem of global warming. The ozone layer acts to protect life on Earth by blocking harmful ultraviolet rays from the sun. The "ozone hole" is a severe depletion of the ozone layer high above Antarctica. It is primarily caused by human-produced compounds that release chlorine and bromine gases in the stratosphere.

NASA and National Oceanic and Atmospheric Administration (NOAA) scientists report this year's (2007) ozone hole in the polar region of the Southern Hemisphere has broken records for area and depth.

"From September 21 to 30, the average area of the ozone hole was the largest ever observed, at 10.6 million square miles," said Paul Newman, atmospheric scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. If the stratospheric weather conditions had been normal, the ozone hole would be expected to reach a size of about 8.9 to 9.3 million square miles, about the surface area of North America. 

The Ozone Monitoring Instrument on NASA's Aura satellite measures the total amount of ozone from the ground to the upper atmosphere over the entire Antarctic continent. This instrument observed a low value of 85 Dobson Units (DU) on Oct. 8, in a region over the East Antarctic ice sheet. Dobson Units are a measure of ozone amounts above a fixed point in the atmosphere. The Ozone Monitoring Instrument was developed by the Netherlands' Agency for Aerospace Programs, Delft, The Netherlands, and the Finnish Meteorological Institute, Helsinki, Finland. 

"These numbers mean the ozone is virtually gone in this layer of the atmosphere," said David Hofmann, director of the Global Monitoring Division at the NOAA Earth System Research Laboratory. "The depleted layer has an unusual vertical extent this year, so it appears that the 2006 ozone hole will go down as a record-setter."

The temperature of the Antarctic stratosphere causes the severity of the ozone hole to vary from year to year. Colder than average temperatures result in larger and deeper ozone holes, while warmer temperatures lead to smaller ones. The NOAA National Centers for Environmental Prediction (NCEP) provided analyses of satellite and balloon stratospheric temperature observations. The temperature readings from NOAA satellites and balloons during late-September 2006 showed the lower stratosphere at the rim of Antarctica was approximately nine degrees Fahrenheit colder than average, increasing the size of this year's ozone hole by 1.2 to 1.5 million square miles.

The Antarctic stratosphere warms by the return of sunlight at the end of the polar winter and by large-scale weather systems (planetary-scale waves) that form in the troposphere and move upward into the stratosphere. During the 2006 Antarctic winter and spring, these planetary-scale wave systems were relatively weak, causing the stratosphere to be colder than average.

As a result of the Montreal Protocol and its amendments, the concentrations of ozone-depleting substances in the lower atmosphere (troposphere) peaked around 1995 and are decreasing in both the troposphere and stratosphere. It is estimated these gases reached peak levels in the Antarctica stratosphere in 2001. However, these ozone-depleting substances typically have very long lifetimes in the atmosphere (more than 40 years).

As a result of this slow decline, the ozone hole is estimated to annually very slowly decrease in area by about 0.1 to 0.2 percent for the next 5 to 10 years. This slow decrease is masked by large year-to-year variations caused by Antarctic stratosphere weather fluctuations. 

The recently completed 2006 World Meteorological Organization/United Nations Environment Program Scientific Assessment of Ozone Depletion concluded the ozone hole recovery would be masked by annual variability for the near future and the ozone hole would fully recover in approximately 2065. 

"We now have the largest ozone hole on record for this time of year," said Craig Long of NCEP. As the sun rises higher in the sky during October and November, this unusually large and persistent area may allow much more ultraviolet light than usual to reach Earth's surface in the southern latitudes.

A climate change report by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) found global warming in the Asia Pacific region could cause sea levels to rise by up to 16 cm (six inches) by 2030 and up to 50 cm (19 inches) by 2070. Rising temperatures will also result in increased rainfall during the summer monsoon season in Asia and could cause more intense tropical storms, inundating low-lying coastal villages. 

Millions of people could become homeless in the Asia-Pacific region by 2070 due to rising sea levels, with Bangladesh, India, Vietnam, China and Pacific islands most at risk, says Australia's top scientific body.

"The coastlines of Asia-Pacific nations are generally highly vulnerable to the effects of climate change, particularly sea-level rise caused by rising global temperatures," said the CSIRO report released on Monday. "Vast areas of the Asia-Pacific are low lying, particularly the small-island states, as well as the large river deltas found in India and Bangladesh, Southeast Asia and China." Sea level rise from 30 to 50 cm (11 to 19 inches) would affect more than 100,000 km (62,140 miles) of coast, particularly China's Pearl Delta and Bangladesh's delta, said the report. 

The effect of climate change on the Asia-Pacific region is demonstrated by the effect of deadly Tsunami in Indonesia and the costal regions. Moreover, the two floods and subsequent typhoon Sidr in Bangladesh last year has caused serious damager to not only crops and lives of people, but also left a devastating effect on the biggest mangrove, Sundarban, Bangladesh.    Moreover, unusual snow storm in the US and draught in Australia and abrupt climatic disasters all over the world is nothing but the result of global warming. The economic cost of these climatic changes will be enormous. The loss of human lives, which can not be measured in economic terms, will also be tremendous.

"As sea level rise exceeds half a meter, the area affected in the Asia-Pacific region rises to over half a million square kilometers, affecting hundreds of millions of people," it said.  "Large areas of Bangladesh, India, Vietnam are inundated and Kiribati, Fiji and the Maldives are reduced to just a small fraction of their current land area." The report also said rising sea levels and increased rainfall would spread infectious diseases in the region, leaving millions more at risk of dengue fever and malaria. 

Sir Nicholas Stern, a former chief economist with the World Bank, warn that governments need to tackle the problem head-on by cutting emissions or face economic ruin. The findings will turn economic argument about global warming on its head by insisting that fighting global warming will save industrial nations money. The United States is the largest emitter of greenhouse gases, most notably carbon dioxide. But Bush pulled the country out of the 160-nation Kyoto Protocol in 2001, arguing that the treaty's mandatory curbs on emissions would harm the economy.

Speaking at a climate change conference in Birmingham, Sir Stern said: "All of [Stern's] detailed modeling out to the year 2100 is going to indicate first of all that if we don't take global action we are going to see a massive downturn in global economies." He added: "If no action is taken we will be faced with the kind of downturn that has not been seen since the great depression and the two world wars."

If we're to have a high chance of preventing global temperatures from rising by 2C (3.6F) above pre-industrial levels, we need, in the rich nations, a 90% reduction in greenhouse-gas emissions by 2030. The greater part of the cut has to be made at the beginning of this period.

Climate change is not just a moral question: it is the moral question of the 21st century. There is one position even more morally culpable than denial. That is to accept that it's happening and that its results will be catastrophic, but to fail to take the measures needed to prevent it. The recommendations are based on stabilizing carbon dioxide and other greenhouse gas levels in the atmosphere at between 450 and 550 parts per million - which would still require a cut of at least 25 per cent in global emissions, rising to 60 per cent for the wealthy nations.

A leading US climate researcher says the world has a 10-year window of opportunity to take decisive action on global warming and avert catastrophe. NASA scientist James Hansen, American climate researchers, said governments must adopt an alternative scenario to keep carbon dioxide emission growth in check and limit the increase in global temperatures to 1 degree Celsius (1.8 degrees Fahrenheit). If the world continues with a "business as usual" scenario, Hansen said temperatures will rise by 2 to 3 degrees Celsius (3.6 to 7.2 degrees F) and "we will be producing a different planet." On that warmer planet, ice sheets would melt quickly, causing a rise in sea levels that would put most of Manhattan under water. The world would see more prolonged droughts and heat waves, powerful hurricanes in new areas and the likely extinction of 50 percent of species.

Moreover, Countries like China and India that constitute about 40 per cent of the world population must also act cautiously to prevent this disaster. World leaders who value human lives over dollar and prosperity must take immediate steps to curb down the causes of global warming without further delay.

Author: Freelance columnist.
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