Global Warming and Drought in The Southwestern U.S. Essay

Pumphrey (2008) rightly observed that until f nervous strainly recently, no one would bought the idea that the realitys mode was changing, let exclusively that it was been influenced by human activities. The first insight into what is today known as spheric change was first conceived by the Swedish scientist Arrhenius, who, late in the 19th century, suggested that the activities of the rapidly developing industries could answer the major planet to warm up. such(prenominal)(prenominal) ideas were often ignored, but everywhere the course of the 20th century, opinions ab outdoor(a) temper change, even rapid humor change were becoming more transparent (Pumphrey, 2008, p.1). As things stand now, there appears to be a growing plenitude of irrefutable evidences that point to the fact that human activities ar affecting the hot up/energy exchange between the earth, the airwave and space (Justus and Susan, 2006). The primary instance of orbicular climate change has been att ributed to the accumulation of carbon dioxide and other air pollutants in the earths atmosphere. These green house gases, as they are now known, form a blanket over the earth atmosphere, and then trapping the suns take fire inside the planet and causation it to warm up (National Resources Defense Council, 2007).A substantial population of the worlds scientist hold up addd that human activities, especially the burning of fogey fuels, sop up increased atmospheric concentrations of carbon dioxide (CO2) by 36% from pre-industrial levels of 280 part per million (ppm) to 380 ppm over the past 150 years, leading to an increase in global average temperature of 0. 9oF over the past 100 years. Consequently, there has been considerable increase in global average temperature and ocean levels, comes of sea water ice in the Artic and melting of the planets continental ice sheets and mountain glaciers (Justus and Susan, 2006).More frightening, however, is the assertion by scientists tha t if green house gases carry on to accumulate at the act rates, more rapid and devastating consequences could dissolver within a short pointedness of time. While scientists largely agree on the evidences pointing to a warming planet, the ghastliness and ramifications of its consequences is often a pillow slip of controversy, doubts and heated debates. The drouth in the Southwestern U. S posits one such example of the controversies and uncertainties surrounding the consequences of global warming. In the history of the Southwestern U.S. , drouth has been a relatively periodic occurrence, due to climate variability that characterizes this role. For example, afterwards reviewing the history of climate changes in the piece, Thompson and Anderson (2005) concluded that over the long term, the climate of the percentage is constantly changing and that in the 18,000 years since the last flash-frozen maximum the southwestern linked States has experienced conditions that ranged fr om practically colder to approximatelywhat tepid than today. Moisture conditions contribute also varied, both through time and crosswise the office (Thompson and Anderson, 2005).However, despite these assertions, scientists through several studies have pointed out that the present multi-year drouth in the region is non another result of climate variability but a consequence of climate change. They assert that the present climate situation might be the raw climate of the region and that thirsty and more sever drouths lies ahead if urgent measures are not taken. The proposed study intends to support and add weight to the contention that climate changes is already impacting the region and that increasing global warming allow increase the severity of drouth in the Southwestern U.S. Purpose Statement McNab and Karl (2003) observe that drouth is a complex phenomenon that can be very difficult to restrain. They contend that the problem with defining drought derives partially f rom the fact that the term could be approached from different perspectives. That, notwithstanding, the central theme that underlie any definition of drought is the absent or deficiency of water. However, they point out that to completely define drought, the component(s) of the hydrologic cycle affected by the water deficit and the time period associated with the deficit, must be specified.The Southwestern U. S is a region vulnerable to droughts due to its variable climatology that derives from its peculiar topography. The entire Southwestern states of the unify States fall into a climatic region generally known as the subtropics. These regions are known to be dry and susceptible to drought because the atmosphere moves water out of those regions into higher(prenominal) planes (Thompson, 2007). It is argued that the evaporation is higher in subtropics and the moist air from here is raptureed to temperate regions at higher latitudes.This climatic condition sometimes causes excessive sobriety (drought) in these regions. The infamous dust bowl conditions of the 1930s and the severe droughts of the 1950s are exemplary examples. Pointing out the vulnerability of the region, Davis (2007) observe that in some years, exceptional drought has engulfed the entire Plains from Canada to Mexico in other years, crimson conflagrations on weather maps have crept down the Gulf Coast to Louisiana or crossed the Rockies to the national Northwest (Davies, 2007).Based on this argument, it is convenient to describe the present drought in the region as a result of such climatic variability. Unfortunately, recent data on global warming indicate otherwise. Scientists have shown that this time, the drought in the region is not just a release phase in climatic conditions, it is a reality that has come to stay. It is evident that this time, it is the base climate that is changing and dire consequences looms ahead.Supporting the argument that the aridness in the Southwestern U. S is di fferent this time, Davis (2007), point out that Lake Powell had move by nearly eighty feet in three years, and crucial reservoirs on the Rio Grande were barely more than mud puddles. The Southwestern winter of 2005-06, meanwhile, was one of the driest on record, and Phoenix went 143 days without a single drop of rain.Noting that some scientists have regarded the present situations as the worst drought in five hundred years and with the several scientific evidences showing the link between global warming and severe drought, Davis concluded that the present climate condition is not simply episodic drought but the regions new normal weather (Davies, 2007). Statement of the Problem Both global warming and droughts omen grave dangers for both the region and the world at large. Despite the sometimes dissenting voices in the science world, there is unanimous certainty that the planet is warming up.The Intergovernmental Panel on Climate Change (IPCC) in its 2007 root stated that it is unequivocal that the planet is heating up and that, with utmost certainty, the warming is caused by human activities. It is clearly understood that increased global temperatures will facilitate the propagation of certain deadly bacteria and the spread of diseases. For example, Kolivras and Andrew (2004) carried out a study that revealed that the presence and spread of four diseases hantavirus, plague, dengue and coccidiomycosis in the Southwestern U. S could be attributed to the increased in temperature in this region.Again, it is clear that higher global temperatures will lead to increase in the incidence and severity of droughts which will affect agricultural production, causing global food crisis. Also, the melting of continental and Artic ice, due to global warming, will cause flooding and other devastating problems that will affect millions of people globally. sour drought, on the other hand, also severely impacts a society. Besides the shortfall of food and water that charac terizes drought conditions, Davis (2007) also point out that drought rapidly destabilizes the natural ecosystem.Buttressing this fact, he observed that, without sufficient moisture to produce protective sap, millions of acres of pinyon and ponderosa pine have been ravaged by plagues of bark beetles these dead forests, in turn, have helped to chivy the firestorms that have burst into the suburbs of Los Angeles, San Diego, Phoenix and Denver, as well as destroyed part of Los Alamos (Davies, 2007). However, despite the frightening consequences of droughts and/or global warming, the real bed here is the mis understanding of the problem at hand.A clear understanding of the real cause and nature of the drought in the Southwestern United States will greatly help in containing the problem before it dumbfound out of hand. In a study for the Lamont Doherty Earth Observatory, Columbia University, Richard Seager and other scientists point out that all the models used for the third Assessm ent propound of the Intergovernmental Panel on Climate Change (IPCC) indicated a general decrease in rainfall in the subtropics during the 21st century and slack drying up of the region with increasing concentrations of atmospheric carbon dioxide (Seager et al, 2007).The present drought in the region is therefore, evidently a consequence of a much bigger problem, the realization of this fact is important in shaping familiar attitudes and opinions required for finding a lasting solution to the problem. Theoretical poser The states of the Southwestern United States fall in a climatic region known as the subtropics. The climate in these regions is characteristically dry because the atmosphere moves water out of these regions. Moist air from these regions is often transported to temperate regions at higher latitudes.This phenomenon is referred to as the Hadley cell (Thompson, 2007). This campaign of moist air away from subtropics induces rising air over the equator and descending a ir over the subtropics. The descending air over the subtropics suppresses precipitancy, which further increase dryness of the regions. With global warming, the blanket of greenhouse gas in the atmosphere heat up the air over the subtropics enabling it to carry and transport more moisture away from the region.Furthermore, with increasing global temperatures, Hadley cell (the flow of air out of the subtropics) expands pole ward, bringing the United States Southwestern region under the increasing influence of descending air, further compromising precipitation and further worsening drought. The link between reduced precipitation and drought was established by McNab and Karl (2003) who asserted that precipitation can be considered to be the carrier of the drought signal and stream flow and ground-water levels can be considered to be the last indicators of the occurrence of a drought (McNab and Karl, 2003).It has been argued that whilst past droughts in the region was because La Nina bro ught cooler ocean temperatures to the equatorial Pacific, which resulted in drier conditions over North America, the present drought is caused by changing climatic conditions characterized by increasing global temperatures that enable more moisture to be transported out of the region and suppressed precipitation.