Most climate scientists agree the main cause of the current global warming trend is human expansion of the "greenhouse effect"
Certain gases in the atmosphere block heat from escaping. Long-lived gases, remaining semi-permanently in the atmosphere, which do not respond physically or chemically to changes in temperature are described as "forcing" climate change where as gases, such as water, which respond physically or chemically to changes in temperature are seen as "feedback's."[1]
Gases that contribute to the greenhouse effect include:
1.Water Vapor
2.Carbon Dioxide
3.Methane
4.Nitrous oxide
5.Chlorofluorocarbons
Climate change is becoming an ever more important issue in our lives. We have come to realise that the modern ways of man place a enormous amount of stress on the Earth that nature simply can not handle. Some of the climatic problems that are developing today, such as global warming, ozone depletion and El Nino, will have severe effects on reef ecosystems all around the world. Reefs might give us an early indication of the effects of global climate changes, as slight variations in sea temperature caused by climatic variations have already been shown to produce extreme responses from reef ecosystems.
The Earths' Life Support System.
The atmosphere is a gaseous envelope which surrounds the planet and revolves with it. It has a mass of about 5.15 x 1015 tons, and is held to the planet by gravitational attraction. The present day atmosphere is nearly uniform up to approximately 80 km above Earth's surface. The main constituents of the atmosphere are oxygen (21%), nitrogen (78%), and argon (0.93%). Other trace gases include water (0.01 - 1%), carbon dioxide (350 parts per million (ppm)), methane and nitrous oxide. The atmosphere plays a major role in controlling the planets' temperature. Only 58% of the energy crossing the outer edge of the atmosphere reaches the earth’s surface (on average) - more on a clear day at the equator. The rest of the incident radiation is either reflected (by clouds, vegetation) back into space or absorbed (by water (clouds), carbon dioxide and other gases). The energy that reaches the earth warms the land and oceans. To keep the system in balance, an equal amount of energy is radiated back out to space. The outgoing energy is of a different wavelength to the incoming energy, and greenhouse gases trap this energy more easily than sunlight, so some heat energy is retained (like under a blanket), and the earth stays at a temperature higher than space (lucky for us). Without the atmosphere, the average surface temperature of our planet would be -18°C. With the present day atmosphere, the average temperature is raised by approximately 33°C to 15°C. This is the Greenhouse Effect - the atmosphere acts like a blanket to hold in some heat. The problem we face today is the enhancement of the Greenhouse Effect, leading to global warming. This Enhanced Greenhouse Effect comes about because of the addition of huge volumes of greenhouse gases into the atmosphere throughout the industrial age. The increased levels of greenhouse gases means that more heat is retained, and temperature increases until a new equilibrium is achieved. The greenhouse gases are carbon dioxide (CO2), methane, nitrous oxide , water vapour, and CFC’s (Chlorofluorocarbons). The main sources of these greenhouse gases are combustion of fossil fuels, devegetation (clearing and burning of forests, urban development) and agriculture (eg cow farts).[2]
[1]https://www.google.com/#pq=whats+the+problem+climate+change&hl=en&cp=13&gs_id=1u&xhr=t&q=problem+of+climate+change&tok=DieqOzCK9FdrIWEImDus6w&pf=p&sclient=psy-ab&source=hp&pbx=1&oq=problem+of+cl&aq=0&aqi=g4&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=59a1bbd79307d996&biw=1280&bih=909
[2]http://www.reef.edu.au/contents/ps/fr_climate.html
By: Robert Rodriguez
No comments:
Post a Comment