The Greenhouse Effect By Prof. Liwayway Memije-Cruz We can debate this or that aspect of climate change, but the reality is that most people now accept our climate is indeed subject to change as a result of greenhouse gas emissions -. Tony Blair The world is warming up because carbon dioxide from smoke and car exhausts collect in the atmosphere and traps some of the heat going back to space, like greenhouse. Carbon dioxide and other greenhouse gases are expected to raise global temperature by an average of 2 degrees Centigrade by the year 2100 causing the polar ice caps to melt, sea levels to rise and freak weather conditions which may cause millions of deaths. Solar radiation interacts with the earth’s surface in several ways. Some portion of this energy is reflected back into space by the Earth’s atmosphere, another portion is dispersed and scattered by the molecules in the atmosphere and a large portion penetrates through the Earth’s atmosphere to reach the surface of the Earth. The radiation reaching the earth’s surface is largely absorbed resulting in surface warming. Much of this absorbed energy is eventually re-radiated in longer infrared wavelengths. As it leaves the Earth, it once again interacts with the atmosphere. Some of this re-radiated energy escapes to space, but much of this is reflected back to the Earth’s surface by molecules in the Earth’s atmosphere. The molecules responsible for this phenomenon are called greenhouse gases. These are water (H2O), nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2). They are called greenhouse gases because they act like the glass in the greenhouse, trapping re-radiated energy. Without these gases most life on Earth would not be possible, as the surface temperature of the Earth would likely be about 60 degrees Fahrenheit colder. The so-called greenhouse gases (GHGs) are naturally occurring gases that keep the Earth warm enough for plants and animals to live in. They are by natural processes like the water cycle, growth and death of plants and animals, decaying of wood and other biodegradable materials, volcanic activities, etc. In the last two centuries, it has been noted that human activities have increased the production of these gases: · Methane (CH4), primarily from agricultural activities such as intensive livestock raising and flooding of rice paddies and also from waste dumps, coal beds and leaks from gas pipelines · Carbon dioxide (CO2), from machines and motors that use coal, oil, and natural gas, and also from deforestation · Nitrous Oxide (N2O), from intensive agriculture · Ozone (O3), in lower atmosphere, indirectly from automobile exhaust fumes · Chlorofluorocarbons (CFCs), from industrial processes · Water vapor is also one of the greenhouse gases. However, it is produced from the naturally occurring water cycle. In essence, greenhouse gases act as an insulator or blanket above the Earth, keeping the heat in. Increasing the concentration of these gases in the atmosphere increases the atmosphere’s ability to block the escape of infrared radiation. In other words, the Earth’s insulator gets thicker. Therefore too great a concentration of greenhouse gases can have dramatic effects on climate and significant repercussions upon the world around us. Climates suitable to human existence do not exist simply above some minimum threshold level of greenhouse gas concentration; rather they exist within a finite window – a limited range of greenhouse gas concentrations that makes life, as we know it possible.
Posted on: Wed, 13 Aug 2014 00:17:20 +0000
Trending Topics
Recently Viewed Topics
© 2015