Role of Humans versus Nature in Global Warming
Global warming, particularly of earths surface, is a reality admitted by all climatologists. Majority of them hold humans responsible for this phenomenon though some skeptics attribute global warming wholly to nature (Stevens, 2000, p. F1, F6). The role of humans versus nature in global warming forms the central point of this article. A perusal of arguments put forth by the majority and those of the skeptics as outlined in the article leads one to the conclusion that for global warming neither humans nor nature can solely be held responsible, together the two have caused the phenomenon (Stevens, 2000, p. F1, F6 GCRIO, 1997).
Greenhouse gases such as carbon-dioxide help in sustaining life by keeping the surface of the earth warm due to their heat trapping and retaining qualities. However, excess of these gases is fraught with negative consequences. According to scientific panel of the United Nations, the average surface temperature will rise by 2 to 6 degree Fahrenheit by 2100 if greenhouse emissions remain unchecked (Stevens, 2000, p. F1, F6). The panel predicts huge disruptions in climate, causing the global sea level to rise and flood many places. It is noteworthy that each individual year since 1992 has found mention in the list of 20 hottest years on record (Union of Concerned Scientists, 2006). By matching the observed and modeled patterns, scientists can now positively identify the human fingerprints associated with the changes which can be seen in the ocean, in the atmosphere, and at the surface(Union of Concerned Scientists, 2006). Present levels of atmospheric carbon dioxide are higher than those measured at any particular point of time during the last 650,000 years.
The Inter-government Panel on Climate reported in 2001, that human activities are responsible for most of the warming recorded over the last fifty years (Union of Concerned Scientists, 2006). By human activities is meant burning of coal, oil and natural gas for domestic, agricultural and industrial purposes, and deforestation. Land use changes, for example clearing land for logging, ranching and agriculture, also lead to carbon dioxide emissions (GCRIO, 1997). Due to these activities, boundary of troposphere, which contains earths weather, has lifted over the last twenty years by 900 feet (Union of Concerned Scientists, 2006).
The skeptics discount the reliability of the temperature samplings showing century long warming trends at the earths surface (Stevens, 2000, p. F1, F6). They point out that scientific models for measuring temperatures on earth have failed to reflect realities about upper atmosphere. The measurements supplied by earth satellites show negligent temperature change in most parts of the upper atmosphere. Dr. Gray and other skeptics believe that surface warming is wholly natural and opine that any future warming will be inconsequential or at the most near the low end of the range predicted by the UN scientific panel (Stevens, 2000, p. F1, F6). Solar energy changes, aerosols due to volcanic eruptions and snow or ice cover changes constitute main natural factors behind climate changes (Union of Concerned Scientists, 2006). Dr. Richard S. Lindzen, an atmospheric scientist and a skeptic, says that disparity of temperatures suggests that happenings at the surface are unrelated to greenhouse effect (Stevens, 2000, p. F1, F6). According to Dr. Michael Oppenheimer, the conclusion of National Research Council that surface warming is real, nullifies the key argument of the skeptics (Stevens, 2000, p. F1, F6).
Experts on both the sides agree about the imperfection of the climate models used (Stevens, 2000, p. F1, F6). The majority view concedes that size of human contribution has not been ascertained so far. In search of truth, the scientists are comparing the effects of man-made and natural factors on global warming by changing one variable at a time in their advanced models. The results indicate that human activities have enhanced heat trapping, retaining emissions and decreased ozone whereas solar energy changes have warmed both the troposphere and the stratosphere. With ozone depletion, lesser incoming sunlight is absorbed, leading to stratospheric cooling. A combined effect has produced an upward shift in tropopausal height, with 80 percent of the same being attributable to human activities (Union of Concerned Scientists, 2006).
All the climatologists agree that concentration of greenhouse gases is on the rise, for instance concentration of carbon dioxide has gone up by approximately 30 percent than what was before Industrial Revolution (Stevens, 2000, p. F1, F6). The substantial increase in global warming for the last twenty five years cannot be explained without taking into account the effect of greenhouse gases though the die-hard skeptics like Dr. Gray attribute it to changes in the movements of heat-bearing ocean currents, and hope that warming will be a few decade phenomenon and thereafter cooling will resume (Stevens, 2000, p. F1, F6).
The future climatic trends cannot be predicted with confidence as the inherent sensitivity of climate system to greenhouse effect is not known. Lack of knowledge about future rise in atmospheric levels of greenhouse gases further complicates the matters. Human efforts to improve efficiency will also impact the gas emissions and will interfere with any prediction about global warming. If one goes by the assertion that nature is wholly behind the phenomenon, not much can be humanly done to ameliorate the situation. Physicist Pablo F. Verdes analysis of data relating to strengths of solar radiations and volcanic activity for past 150 years, demonstrates that theses natural causes do not fully explain the observed warming (ScienceDaily LLC, 2007).
Inwardly, all the climatologists know that question of the causes behind global warming have not been conclusively decided as scientists have not been able to segregate the effect of greenhouse gases from natural climate fluctuations. As a study published in the American Meteorological Society has concluded, a combination of natural and human-made factors is responsible for warming (Stevens, 2000, p. F1, F6).
Global warming, particularly of earths surface, is a reality admitted by all climatologists. Majority of them hold humans responsible for this phenomenon though some skeptics attribute global warming wholly to nature (Stevens, 2000, p. F1, F6). The role of humans versus nature in global warming forms the central point of this article. A perusal of arguments put forth by the majority and those of the skeptics as outlined in the article leads one to the conclusion that for global warming neither humans nor nature can solely be held responsible, together the two have caused the phenomenon (Stevens, 2000, p. F1, F6 GCRIO, 1997).
Greenhouse gases such as carbon-dioxide help in sustaining life by keeping the surface of the earth warm due to their heat trapping and retaining qualities. However, excess of these gases is fraught with negative consequences. According to scientific panel of the United Nations, the average surface temperature will rise by 2 to 6 degree Fahrenheit by 2100 if greenhouse emissions remain unchecked (Stevens, 2000, p. F1, F6). The panel predicts huge disruptions in climate, causing the global sea level to rise and flood many places. It is noteworthy that each individual year since 1992 has found mention in the list of 20 hottest years on record (Union of Concerned Scientists, 2006). By matching the observed and modeled patterns, scientists can now positively identify the human fingerprints associated with the changes which can be seen in the ocean, in the atmosphere, and at the surface(Union of Concerned Scientists, 2006). Present levels of atmospheric carbon dioxide are higher than those measured at any particular point of time during the last 650,000 years.
The Inter-government Panel on Climate reported in 2001, that human activities are responsible for most of the warming recorded over the last fifty years (Union of Concerned Scientists, 2006). By human activities is meant burning of coal, oil and natural gas for domestic, agricultural and industrial purposes, and deforestation. Land use changes, for example clearing land for logging, ranching and agriculture, also lead to carbon dioxide emissions (GCRIO, 1997). Due to these activities, boundary of troposphere, which contains earths weather, has lifted over the last twenty years by 900 feet (Union of Concerned Scientists, 2006).
The skeptics discount the reliability of the temperature samplings showing century long warming trends at the earths surface (Stevens, 2000, p. F1, F6). They point out that scientific models for measuring temperatures on earth have failed to reflect realities about upper atmosphere. The measurements supplied by earth satellites show negligent temperature change in most parts of the upper atmosphere. Dr. Gray and other skeptics believe that surface warming is wholly natural and opine that any future warming will be inconsequential or at the most near the low end of the range predicted by the UN scientific panel (Stevens, 2000, p. F1, F6). Solar energy changes, aerosols due to volcanic eruptions and snow or ice cover changes constitute main natural factors behind climate changes (Union of Concerned Scientists, 2006). Dr. Richard S. Lindzen, an atmospheric scientist and a skeptic, says that disparity of temperatures suggests that happenings at the surface are unrelated to greenhouse effect (Stevens, 2000, p. F1, F6). According to Dr. Michael Oppenheimer, the conclusion of National Research Council that surface warming is real, nullifies the key argument of the skeptics (Stevens, 2000, p. F1, F6).
Experts on both the sides agree about the imperfection of the climate models used (Stevens, 2000, p. F1, F6). The majority view concedes that size of human contribution has not been ascertained so far. In search of truth, the scientists are comparing the effects of man-made and natural factors on global warming by changing one variable at a time in their advanced models. The results indicate that human activities have enhanced heat trapping, retaining emissions and decreased ozone whereas solar energy changes have warmed both the troposphere and the stratosphere. With ozone depletion, lesser incoming sunlight is absorbed, leading to stratospheric cooling. A combined effect has produced an upward shift in tropopausal height, with 80 percent of the same being attributable to human activities (Union of Concerned Scientists, 2006).
All the climatologists agree that concentration of greenhouse gases is on the rise, for instance concentration of carbon dioxide has gone up by approximately 30 percent than what was before Industrial Revolution (Stevens, 2000, p. F1, F6). The substantial increase in global warming for the last twenty five years cannot be explained without taking into account the effect of greenhouse gases though the die-hard skeptics like Dr. Gray attribute it to changes in the movements of heat-bearing ocean currents, and hope that warming will be a few decade phenomenon and thereafter cooling will resume (Stevens, 2000, p. F1, F6).
The future climatic trends cannot be predicted with confidence as the inherent sensitivity of climate system to greenhouse effect is not known. Lack of knowledge about future rise in atmospheric levels of greenhouse gases further complicates the matters. Human efforts to improve efficiency will also impact the gas emissions and will interfere with any prediction about global warming. If one goes by the assertion that nature is wholly behind the phenomenon, not much can be humanly done to ameliorate the situation. Physicist Pablo F. Verdes analysis of data relating to strengths of solar radiations and volcanic activity for past 150 years, demonstrates that theses natural causes do not fully explain the observed warming (ScienceDaily LLC, 2007).
Inwardly, all the climatologists know that question of the causes behind global warming have not been conclusively decided as scientists have not been able to segregate the effect of greenhouse gases from natural climate fluctuations. As a study published in the American Meteorological Society has concluded, a combination of natural and human-made factors is responsible for warming (Stevens, 2000, p. F1, F6).
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