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WHAT’S WRONG WİTH THE WEATHER?
Although climatologists believe that global warming may eventually trigger extreme weather variations like the ones we are experiencing, they say it is too early to prove a direct connection. The outbreak of freakish weather could also have been partly caused by one or more of the following large-scale atmospheric events:
EL NINO
To meteorologists, the weather phenomenon named after a child is not a theory, but a recognisable and recurrent climatological event. Every few years around Christmas-time, a huge pool of warm sea water in the western Pacific begins to expand eastward toward Ecuador and disrupts weather patterns across half the earth's surface. The El Nino that began last year and is now breaking up has been linked to the flooding in Latin America, the unseasonably warm winter in North America and the droughts in Africa.
PINATUBO
The full effects of the eruption of Mount Pin atubo in the Philippines last June - probably the largest volcanic explosion of the 20th century - are starting to be felt this year. The volcano released 20 million tons of gas and ash into the stratosphere, where they formed a layer of dust that will scatter sunlight and could lower temperatures - by a quarter of a degree Celsius - for the next three or four years. Smoke from the Gulf-war fires, by contrast, never reached the stratosphere and had no measurable effect on the world's weather.
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GREENHOUSE GASES
It is known that the level of carbon dioxide, methane and other heat-trapping gases in the atmosphere has increased 50% since the start of the Industrial Revolution. Measurements also indicate that the world's average temperature has increased just over half a degree Celsius over the past 100 years. Computer models suggest that as the build-up of greenhouse gases continues, average temperatures could jump 1 .70C to 50C over the next 60 years. Some scientists speculate that even a small rise in average temperatures could lead to greater extremes in weather patterns from time to time and place to place.
The problem with sorting out these influences is that they interact in complex ways and may, to some extent, cancel each other Out. Pinatubo's cooling effects could counteract the warming caused by greenhouse gases, at least over the short term. At the same time, El Nino' 5 warming influence seems to have suppressed the early cooling effects of Pinatubo.
Predicting the weather is, in the best of circumstances, a game of chance. Even with the most powerful supercomputers, forecasters will never be able to see ahead more than a couple of weeks with any accuracy. The main reason is that some of the influences that shape our weather are man-made. Experts say it could be 20 or 30 years before they know for certain what effect the build-up of greenhouse gases, the destruction of ancient forests or the depletion of the ozone layer have had. Policy-makers looking for excuses not to halt those trends will always be able to point to scientific uncertainty. As climatologist Schneider puts it, "We're insulting the system at a faster rate than we can understand." The risk is that by the time we understand what is happening to the weather, it may be too late to do anything about it.
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