Global warming is the gradual increase in the average temperatures of Earth caused by an increase in Greenhouse Gases (GHG) in Earth's atmosphere. An unprecedented increase in GHG has induced the warming up of Earth. Since global warming impacts entire biosphere and ecosystems, watersheds are also distorted through warming of climate. The paper defines watersheds, their role in ecosystem, and explanation of changes that have taken place in Wabash watershed. Wabash watershed is composed of smaller watersheds such as Upper Wabash Watershed, Lower Wabash, Little Wabash Watershed, Middle Wabash-Busseron, and Middle Wabash-Little Vermilion Watershed. Human agency has caused the global warming to increase over a period of last two decades, though its signs are obvious much before that. Increases in average lower temperatures, precipitation, and stream runoff are some evident outcomes of global warming. Wildlife, water resources, agriculture, and human health will have an adverse impact in Wabash watershed area due the climatic warming phenomenon.
The unprecedented increase in human population and resulting economic activity has taken place at the cost of unsustainable use of natural resources. Water is one such natural resource that has been impacted by this activity. A watershed is such basin like geographical area in which all water, whether under it or flowing above, is drained to same low-lying area. In fact watersheds range from largest to smallest of sizes. Wesley Powell defines watershed a 'bounded hydrologic system' in which all species, humans as well as animals, are make one community based on water source. Watersheds do not have definitive shape or size, they cross cities, states, and even national boundaries. Wabash watershed is also one of the largest watersheds of State of Indiana whereby the watershed covers the cities of Muncie, Bloomington, Lafayette, Wabash valley, Anderson and Terre Haute. Wabash River is the main tributary in which the water of Wabash watershed flows, that in turn drains into the Ohio River.
Recreation, wildlife maintenance, and natural resources availability are all dependent on areas that form the watersheds (Gregersen, Ffolliott & Brookes, 2008). The essay is composed of five parts including the introduction. Part II will describe the watersheds and their relationship with our ecosystem. Evidence of global warming and resulting impact on watersheds will be highlighted in section II. Section III will highlight the Wabash watershed area with respect to change in biosphere of area. Evapotranspiration, surplus/deficit conditions and runoff/stream flow will also be highlighted. Section IV will describe the role human agency plays in distorting the environment. This section also highlights the potential impact of global warming in Wabash area with a succinct discussion on improvement measures being initiated. The report will conclude by stating the implications of study and reporting the lessons learned.
Watersheds and relationship with Global warming
In order to maintain the effectiveness of our natural ecosystems, plentiful drinking as well as agricultural water is made available through watersheds. In total Wabash watershed is composed of following smaller watersheds. Upper Wabash Watershed, Lower Wabash, Little Wabash Watershed, Middle Wabash-Busseron, and Middle Wabash-Little Vermilion Watershed. Since human use of land and water impacts the way that watersheds holds and disseminate the water, the issue of managing watersheds has come in limelight due to the phenomenon of 'global warming'. Excessive erosion due to de-forestations, un-sustainable water use, water pollution, and increase in downstream sedimentation has caused irreparable damage to watersheds. The gradual warming of climate, with rise in average temperatures of Earth is known as global warming. Stream discharge is main feature of watersheds that impacts all the downstream populations. Global warming causes increase in stream discharge, thus making the watersheds become detrimental to ecosystem itself during the rainy season (McCabe & Wolock, 1999). The Intergovernmental Panel on Climate change presented its fourth assessment report in which it was conceded that 0.74 "C increase in global average temperature had been recorded in period during past 100 years. The ice cover in great lakes of Midwestern region, of which Wabash watershed is part of, is observed to have got uncovered since 1970 to 2010 from being 90% to 50% respectively.
Increase in precipitation and minimum temperatures
The environment protection agency (EPA USA) denotes the geographical area that includes Indiana, Ilion's, and Ohio as Region 5 composed of Midwestern States. The impacts and vulnerabilities of global warminghave increased with every passing year. The fourth assessment report of IPCC observed that the number of hot days and nights have increased during the last 100 years and the trend is likely to continue in the future (IPCC, 2013). The maximum threshold temperatures have also got raised with a decrease in number of cold days. The natural ecosystems and crops cultivation will be impacted by such changes whereby the number of frost days also decrease with passage of each year. Precipitation is also reported to have increased in high latitude areas whereas a decrease of precipitation in medium latitude areas. Intensification in rainfalls will likely impact the high latitude areas with frequent occurrences of large scale and flash floods. Melting of snowpack and glaciers will also be early in the summer season in higher latitude areas with severe climate impact on low lying areas. Midwest region in which the states of Indiana and Ilion's lie, home to Wabash watersheds, temperatures during last decades have increased. With frequent heat waves and fewer cold waves, the regions are one of the most effected by global warming and distortion of Wabash watershed. Precipitation levels have also increased two fold as compared to the last century. Further, average temperature in the regions is estimated to increase by 3°F and could increase to 10°F on average. Illinois and Michigan will have summers similar to that of Texas (Karl, Melillo and Peterson,2009; EPA, 2013). Loss of species and natural habitats is expected as an outcome of this warming up of climatic temperatures.
With an increased levels of average temperatures in Indiana, Ilion's, and Ohio, increased illness due to heated temperatures and heavy precipitation along with occasional droughts will be the main impact that Wabash watershed areas will go through. The quality and availability of water in Wabash watershed areas will also be potentially impacted by the gradual rising of temperatures. These changes will not come unaccompanied but bring more disruptions in agricultural productivity, recreation, and shipping industry. The lakes will become more inundated with water whereas rivers will have less average water in them. In summers, amount of floods and droughts will also increase. All the changes in ecosystem are interconnected. The increase in levels of precipitation, from 37 inches in 1961 to 55 inches in 1991, the annual change in precipitation has been abrupt. The five-year change in precipitation level is vital to understand the change. From 38 inches in 1963, the level increased to 40 inches in 1968. Year 1989 recorded only 35 inches of rainfall whereas in 1991 this increased to 55 inches. Thus the scientists observed that frequent droughts and floods will appear as a consequence of temperature and precipitation changes are verifies.
Run off and annual temperatures increase
The data of annual average temperatures in the Wabash Valley indicate that there is an increase in the temperature since 1980. From being 61.5°F in 1980, the temperature has got raised to 63.5°F, a net increase of 2°F over a period of 10 years. The annual runoff in the area also represents an increase from 12 inches in 1963 to 17 inches in 1984. The last reported year 1991 had 22 inches of annual runoff in the area whereas in 1987 it was only approximately 5 inches. This abrupt but gradually increasing runoff will result in increased stream discharge. Early snow melting is also an outcome of increase in average annual temperatures, both lower and higher end temperatures. Westerling, Hidalgo, Cayan & Swetnam (2006) conducted an investigation regarding wildfires in the Western part of the U.S. And concluded that rather than land use, the wildfires were associated to early snow melting and increased temperatures in summers and spring. The climatic changes have induced the natural catastrophes in many regions of the world. Flash floods in Queensland in Australia as well as in Brazil and China in recent years have raised the issue on a worldwide scale. The U.S. is not the only causality of such unprecedented change in climate. More temperatures in summer coupled with less precipitation in summer is an anticipated outcome in years to come, those around 2050-2080 (Karl, Melillo and Peterson, 2009).
The accelerated cycle of precipitation and runoff will result in an increased flow into the oceans of the world. The global warming will as well induce the glacial melting and combination of both these factors will result in increasing the level of oceans. It has also been reported by some researchers that 18% more water was fed into oceans in 2006 as compared to 1994 due to the fast melting of polar ice and increased river flow in oceans. On an annual basis, the increment of ocean water is reported…