El Nino - Pinatubo - Greenhouse Gases
– WHAT’S WRONG WITH 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. (This article was published in 90’s)
The full effects of the eruption of Mount Pinatubo 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.
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 1.7°C to 5°C 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’s 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 abie 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 if.
A. Mark the statements as True (T) or False (F).
1. Cümatologisîs have enough evidence to prove that there is a connection between global warming and weather variations.
2. The effects of a major voicanic eruption may be felt a year after it happens.
3. There was a fifty per cent increase in the level of heat-trapping gases when the industrial Revolution started.
4. The fact that temperatures have noi fallen despite the cooling effects of Pinatubo is probably because of the warming effects of Ei Nino.
B. Mark the best choice.
1. According to climatoiogists, .
a) weather variations are due to global warming
b) there isn’t a connection between global warming and weather variations
c) large-scale atmospheric events may be the cause of weather variations
d) weather variations cannot be caused by one atmospheric event
2. Which of the following is not correct about “El Nino”?
a) It is a climatological event which carries the name of a child.
b) It takes place every year around Christmas-time.
c) It starts in the western Pacific.
d) It leads to changes in weather patterns.
3. The gas and ash released by Mount Pinatubo .
a) have had the same effect as the smoke from the Gulf-war fires
b) have brought about a decrease in temperatures
c) trap sunlight and prevent it from reaching the earth
d) formed a layer of dust in the stratosphere
4. Weather prediction is a game of chance mainly because .
a) there is a complex interaction between atmospheric events
b) forecasters are not able to make accurate long-term predictions although they use supercomputers
c) not all the factors that affect weather patterns are natural
d) forecasters are not sure whether atmospheric events cancel out each other’s effects
5. Which of the following is not correct?
a) According to experts, it is now too early to determine the effects of human activities on the weather.
b) It is unlikely that there will be a rise in average temperatures in the coming years.
c) Policy-makers are not in favour of making any changes in the present trends.
d) Some measures should be taken against the change in weather patterns before it is too late