“Greenhouse gas emissions from tectonic movements, anthropogenic activities, etc.” (Britanica.com) leads to “greenhouse effect” such as alteration of the global climate. The greenhouse gases leads to increased temperatures within the earth’s atmosphere. Due to the increased temperature, as the greenhouse effects increases, climate change occurs. Climate change is the gradual and steady change of climate over a long period of time. One of the effects of climate change is drought. Drought has several definitions depending on the area or profession in question. In general, drought comprises of a prolonged periods of low precipitation in areas that usually have high precipitation. It thus leads to shortage of water, crop failures, and reduction of forested regions (Craig D. Allen and David D. Breshears, 1998). In this paper, the causes, effects and solutions to the causes of drought are discussed briefly.
Drought is caused by wind. It happens when dry air blows over a region swept by moisture laden air. The dry wind carries away the moisture leaving the region with dry air. Air with moisture in the atmosphere is important in the condensation and formation of rain or snow. Therefore, when it is blown away and replaced with dry air, condensation does not take place. Therefore, the region does not receive the required amount of precipitation. Ocean currents are entirely wind, when they blow from the ocean they contain some moisture, which rises up to condense and form rain or snow. When dry air blows across the ocean, the currents are forced to change direction thus, the region surrounding the ocean remains with dry air. This air and the sun facilitate evaporation of the remaining moisture in plants and the ground resulting to dryness in the environment. If such blowing of ocean current is prolonged, the region is prone to suffer from drought (CRS report, 2014).
The third cause of drought is anthropogenic factors. Human activities contribute significantly to the occurrence of drought. For example, clearing of forests for both settlement and agricultural activities reduces the vegetation cover in a region. With continued increase of population (Chapter 3, IPCC, special report) and the demand for land for settlement and farming, large tracts of land are cleared to pave way for both settlement and agriculture. The results of such activities are little vegetation cover leading to minimal transpiration. Although the temperature rises due to accumulation of greenhouse gasses, precipitation would be little due to the reduced transpiration.
Excessive extraction for irrigation, domestic use as well as industrial use leads to reduction of surface water. When many farmers install water pipes that direct water into the plantations without correct regulation may result to water wastage and depletion in lakes and rivers. Water in lakes and rivers evaporates during hot seasons, rises and condenses to form rain or snow and the region experiences regular rainfall, but when the streams are dried through excessive irrigation, evaporation does not take place and rain is not formed thus, irregular rainfall and drought are experienced (California Department of Water Resources, California’s Drought of 2007-2009)
There are several solutions to drought. The first solution is through afforestation and re-afforestation programs. Through afforestation, the regions that do not have trees in a country or region are planted with different species of trees. Increased vegetation cover reduces greenhouse gasses by acting as carbon sinks. Therefore, mitigation in areas where climate change is caused by increased greenhouse gases would reduce significantly. Again, increases vegetation cover would increases the evapotranspiration in the area and hence increase the amount of precipitation experienced in a region.
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http://www.britannica.com/EBchecked/topic/683450/greenhouse-gas on June 30, 2014.
Craig D. Allen and David D. Breshears (1998). Drought-induced shift of a forest–woodland ecotone: Rapid landscape response to climate variation. vol. 95 no. 25 pp. 14839–
14842. Retrieved from http://www.pnas.org/content/95/25/14839.full on June 30, 2014.
Chapter 3, IPCC Special Report on Emissions Scenarios, 2000. Intergovernmental Panel on Climate Change. 2000. Retrieved from
http://www.grida.no/publications/other/ipcc_sr/?src=/Climate/ipcc/emission/049.htm on June 30, 2014.
Congressional Research service (2014). Drought in the United States: Causes and Current
Understanding. Retrieved from http://fas.org/sgp/crs/misc/R43407.pdf on June 30, 2014.
California Department of Water Resources, California’s Drought of 2007-2009—An Overview