 |
|
|
|
by Cheryl L. Jenkins PhD
Scientists now have indisputable evidence that our climate is changing. Experts predict a sharp and sustained increase in average global temperatures, melting of the polar ice caps and rising seas. They only thing they cannot be certain of is how quickly these changes will occur.
Climate change is a very complex phenomenon with many contributing factors. In order to fully understand the implications of climate change scientists must have a sound understanding of those factors that increase global temperatures, and those that decrease global temperatures. Since the late 1800s scientist have been recording changes to our climate and carefully considering those factors, both natural and those caused by humans, that affect our climate and developing ways to simulate, and therefore predict their long-term effects on the world we live in. The Greenhouse Effect and Our Carbon Footprint The suns radiation falls upon the earth’s surface where it is absorbed and later radiated as heat towards space that warms the atmosphere. The greenhouse effect is a natural process that prevents some of this heat escaping into space; it remains in the earth’s atmosphere resulting in increased temperatures. Gases that prevent heat escaping from the earth’s atmosphere are known as greenhouse gases, these include carbon dioxide and methane. It is clear that human activity since pre-industrial times has changed the composition of the atmosphere and increased the levels of carbon dioxide contributing to the greenhouse effect. The effect on earth’s ecosystems of the increased temperatures caused by our carbon dioxide gas emissions is known as our carbon footprint. Rising Global Temperatures The Hadley Centre, a UK research centre for the Met Office, has reported that since the mid-1930s the average global near-surface temperatures have increased continuously. Current climate simulations predict that if we do not reduce our carbon footprint - by cutting harmful gas emissions - the average increase in global temperatures will be between 1.5 and 5.8°C by 2010. Increases in temperature will be subject to regional variations with areas such as India, Africa, South America and the northern Polar Ice Caps being subject to the highest increases in temperature. Rising Sea Levels Increases in global temperatures, particularly those affecting the Polar Regions, will result in melting of ice regions around the globe. Evidence of retreating glaciers, ice and snow regions have been recorded; since 1850 20% of alpine glaciers have retreated. Glaciers are also reported to be retreating in the Himalayas and the Andes. The snowcap of Mount Kilimanjaro in Africa is predicted to disappear in 20 years.
Sea levels are predicted to rise as a consequence of melting ice and the increase in ocean volume caused by higher ocean temperatures. Change in the sea level will be much greater in the 21st Century than in the 20th Century. These levels will continue to rise for millennia even after stabilization of atmospheric conditions. Eventually, cities such as London, Liverpool and Hull may have to be abandoned. Changes in sea levels may also influence ocean currents, which can have a critical impact on our climate. Climate Change in the UK Remember the heat wave of 2003 when temperatures in the UK reached 38.5°C? If current simulations are correct our summer temperatures are set to continue increasing until this becomes the typical UK summer. Without changes to our greenhouse gas emissions and practices that are damaging the environment these temperatures will continue rising and 2003 will be a cool summer in comparison. For some of us in UK the prospect of a warmer climate might sound rather pleasant; however, the reality may be somewhat different. When seawater freezes close to Greenland some salt is left behind which makes the surrounding water heavier. This heavy water falls to the ocean floor and draws warm water from the south to replace it. This creates the Gulf Stream current, which warms our climate. As a result of increasing temperatures, ice is melting around Greenland, diluting the salt and weakening this process, which may slow or perhaps even stop the current. As yet, scientists do not fully understand what effects this may have on our weather and our climate. Our Climate, Our Problem Global temperatures are increasing, ice is retreating, seas are rising and ocean currents are changing. This in turn will change the weather we experience; storms, droughts and heat waves will become more frequent. Consequently, air quality will decrease and no doubt our health, let alone that of future generations, will suffer. Our environment is responding to our actions. We are all responsible for climate change so we should all be part of the solution.
|
See Also:
|
|||||
|
||||||
