Over the past one hundred years, Earths average surface temperature has increased by approximately 0.74 degrees Celsius and for the past 16 years from 1995-2010, 15 of those years were among the warmest years in the instrumental record of global surface temperatures since 1850. (IPCC, 2007) It has been shown that since the start of the Industrial Revolution, atmospheric carbon dioxide concentrations have risen exponentially and steadily as a result of the combustion of fossil fuels as an energy source for industrialized nations and developing nations alike. Apart from that, deforestation also play a major role in global warming as forested lands are typically cleared and burned for farming.
The sea levels have as a result of the associated thermal expansion of ocean waters and melting of glaciers, shown to rise at a rate of 1.8 millimeters per year in the past century. A rise in sea levels will have serious implications on coastal environments or small islands from the perspectives of both natural ecosystems and human populations as a large portion of the human population live in coastal areas. There would be direct inundation of low-lying wetlands and dryland areas, increased salinity of estuaries and aquifers, heightened storm surges and floods.
Apart from that, changes in the global climate patterns will exacerbate an already increasing problem of feeding the world population, which is predicted to increase to approximately 9 billion from the current 7 billion by 2050. Dominant food crops like corn, rice, wheat, are likely subjected to abnormal changes in temperature and moisture that control growth, survival, and reproduction. Shifts in the geographic range of some crop species may result in significant changes in regional land use patterns that come with social and potentially hefty economic costs. According to a major study conducted by the Environmental Change Unit at Oxford University which carried out a collaborative study with agricultural scientists from 18 countries to examine the regional and global implications of climate change, there would be an up to five percent reduction of global production of cereal crops and the current disparity in cereal crop production between developed and developing countries will be extended further.
Results of the study, in general, showed that agricultural production in developed countries, which are mostly located in the temperate regions, would increase while agricultural production in developing countries as a whole, would decrease by approximately ten percent, exacerbating the widespread hunger issue common in those countries. As cultivation shifts polewards, plant growth and production would be largely affected by changes in the distribution of rainfall and the increase of ultraviolet radiation, and aggravated problems of salinity, erosion, and desertification. Extreme climatic events would also occur more frequently. Warmer temperatures may cause some crops to grow faster than usual and reduce yields during the summer time when the temperature goes above the optimum growing temperature.
Aside from that, more extreme weather events like floods and droughts with extreme temperature and precipitation changes can prevent cereal crops from harvest at all. Take for instance, in 2008, the Mississippi River flooded just prior the harvest period for several crops, resulting in a massive loss of revenue for farmers. Also, pests, weeds and fungi favored by a warmer climate would continue to proliferate and build up resistance through sexual recombination, to pose an even greater threat to current domesticated crop varieties. Many pest, weeds and fungi thrive under warmer, wetter climates with increased carbon dioxide levels. Currently, farmers spend billions of dollars every year to combat these threats and with the changes in climate, it is predicted that the ranges of weeds and pests are likely to expand northward, potentially creating new problems for farmers crops previously unexposed to these species.
In order to combat climate change from an agricultural standpoint, farmers can adapt by adjusting planting patterns, practice soil management techniques in response to the changing weather patterns. There are various methods like contour and strip cropping and no-till reduced tillage that can help prevent soil loss due to wind and water erosion. Similarly, farmers could consider planting trees and shrubs for the purpose of providing wind barriers to reduce soil erosion. Apart from that, crop rotations like the planting of corn for a growing season and soybean the next growing season, limits the likelihood that pests can proliferate and potentially reduce use of nitrogen fertilizers.
Farmers could also apply manure or leguminous cover crops in place of chemical fertilizers. While such methods are useful to combat climate change, some of the methods may not be feasible in certain areas and even if they are feasible, the yields will not necessarily match the amount of conventional farming.
As the climate changes, the demand for Federal risk management programs may increase and farmers could potentially invest in the development of droughttolerant varieties and even consider biotechnology. Genetically modified crops, made for the purpose of higher yields and little to no use of chemicals, may potentially negate the effects of climate change to a large extent if it is easily made and widely implemented. Unfortunately, there are limitations in each technology and it takes a variety of ecosystems to make changes that will cause a significance, in reducing the impact of climate change.
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