Is Human Activity A Substantial Cause Of Global Climate Change? Introduction
There is a big debate with seriously opposing views regarding the cause of global climate change. The United States Academies of science together with NASA and The National Oceanic And Atmospheric Administration lead the pack of organizations, which feel that human activity, has play a big role in contributing to climate change. Activities like, fuel combustion, and clearing of forests have caused have resulted in considerable carbon dioxide increase in the atmosphere, therefore causing global warming. This has been evidenced by melting sea ice, glacial retreat, and extreme weather like intense heat waves, droughts and powerful hurricanes. This group hence suggests that there needs to be an urgent international action taken to restrain human destruction and the resulting dismal consequences. The opposing view has been that, human activities generate greenhouse emissions but they are too infinite to cause climate change. This pack is led by organizations including the Heartland Institute, the American Association of petroleum geologists among others. Their argument is that the earth’s carbon sinks, the oceans and vegetation are able to absorb all of the carbon dioxide emitted by human activities as the emission are small and insignificant. The global warming thus must have resulted from natural causes like fluctuating sun’s heat and oceanic currents. Human Activity is not Substantial
The past 3000 years have had an average variation of temperature of -/+ 5°F. Therefore, looking at the temperature rise in the 20th and 21st centuries, its 1-1.4°F thus falls in this range. It is easy to conclude that there has not been any considerable climatic change (Soon, & Baliunas, 2003, p.103). In 2003, a group of researchers at
Harvard-Smithsonian center for Astrophysics proved that the temperature rise during the period range from 1000s to 1100s AD before extensive combustion of fossil fuel begun was equivalent to the period of industrial revolution when fossil fuel use was increasing dramatically, that is 1900s to 1990s (Soon, & Baliunas, 2003, p.103).
Global warming causes the increasing carbon dioxide levels, but not vice versa. The reason being that, as temperatures rises, carbon dioxide is released to the
atmosphere from the ‘carbon sinks’ like from the oceans. Analyses of ice core samples have indicated that from the previous climatic cycles, the periods of global warming came ahead of global rise in carbon dioxide (Caillon, et al, 2003, p.1728).
The release of carbon dioxide from human activities is not sufficient to cause climatic changes because the earth has a mechanism of regulating the gas. Any increment in the carbon dioxide is naturally balanced by carbon sinks in oceans, vegetation and other sinks, which increase their activities to consume more carbon dioxide (Caillon, et al, 2003, p.1729). About 50% of the emitted carbon dioxide from combustion of fossil fuels and other human activities is already absorbed.
Scientific evidence indicate that the global warming and cooling are as a result of fluctuating sun’s heat, a phenomenon called solar forcing, and not as result of minor greenhouse effect of gas emissions (CO2 and CH3) from human activities (Soon, 2007, p. 102). Climatic studies show that solar irradiance increased at 19% rate between 1900 and 2000 in correlation to the rise in surface temperature of the United States.
Because of the inherent changeableness of climate systems, future climate cannot be predicted based on past models. Climate models cannot accurately simulate future changes. For instance, the ice age period is difficult to simulate. Besides,
recreating climates like Miocene and Cretaceous have proven not reproducible (Soon, 2007, p. 105). If model of past climate cannot replicate those climates, then they cannot be relied on for predicting the future climatic changes.
Global warming is the main concern for many interested parties and it is
characterized by higher temperatures. As an opponent of the idea that global warming is caused by human activities, I note that increasing temperature are due to water vapor, a major gas in the atmosphere and not by carbon dioxide. Water vapor
concentration in the atmosphere is increased by natural climatic activities like oceanic current and storms (Solomon, et al., 2010, p.1221). The NOAA researchers conducting a related study and confirmed that water vapor increased the rate of global warming in the 1990s at a rate of 30%. In the past two decades, there were increased incidences of hurricanes including hurricane Katrina. However, it is obvious that these climatic
conditions were not caused by human activities rather cyclical tropical patterns due to natural oceanic activities.
The deep ocean currents result in warming up of the earth’s atmosphere and cooling in long-term cycles. The minor effect greenhouse effect from the carbon dioxide gas cannot match that impact. It is interesting how global cooling of 1940 to the 1970s and the warming effect from 1970s to 2008 coincide with the changes in ocean currents and cloud cover as influenced by Pacific Decadal Oscillation (PDO). The PDO is a natural phenomenon that leads to rearrangement of atmospheric and oceanic fluid circulation patterns (Spencer, 2008, p.4).
The oceanic acidity has been observed to increase in 20th century; however, these increases are not abnormal since similar fluctuations have been happening in the
past 7,000 years. The average surface ocean water PH is normally about 8.1 though in recent years it has fallen by averagely 0.1 since the industrial revolution period begun (Watts, 2009, p.8). Since neutral pH is seven, then this purported oceanic acidity is a misleading notion.
The changes in ocean current form the major cause for melting Greenland Ice Sheet, Arctic Sea Ice and Arctic Permafrost. The 20th century period was marked by two arctic warming periods and a cooling period (1940s to 1970s) separating them (Chylek, et al., 2009, p.10). Drawing from peer-reviewed studies in 2009 in geophysics, natural changes of oceanic current are the main causes on the climatic changes.
There is general agreement that the warming up of the earth in the 20th century was based on flawed temperature recordings. The recording were done from the surface monitoring stations created by national weather services, these stations are normally tainted by effect known as the ‘heat island effect’ (Watts, 2009, p.9). In the year 2009, study results were published by the Heartland institute suggesting that 89% of the national weather service monitoring stations were located too close to artificial heat sources like heaters, and asphalt parking lots etc (Watts, 2009, p.10).
The warm 1980s and 1990s can be attributable to natural causes. Over the past two to three decades, the temperatures of the earth have increased at about 0.2 to 0.3°C. There have been such trends of temperature rises in the past as well. thus, they do not entirely confirm that human activity must have caused the changes (Soon, 2007, p. 107). The recordings of the period 1890 to 1910, for instance, there was an increase of 0.2°C per decade. That was much greater than the 0.17°C recorded in 1980s to
2000s. During that time, human activity was not intensively causing greenhouse gas emissions, as it was pre-industrial revolution period (Soon, 2007, p. 108).
The cooling and warming cycles before the 1940s must have cause by natural phenomena since no anthropogenic influence on climate can be proven during those times. Especially as indicated earlier, from 1910 to 1940, the rise came too early for carbon gas emission to have caused it (Soon, & Baliunas, 2003, p.106). Recent rises are hence no evidence of human activity causes.
Evidence from ancient climate confirms that there have similar major changes in the carbon dioxide concentration in the atmosphere in the earth’s history. Compared with the temperature rise during same periods show that probably the earth’s climate is sensitive to carbon dioxide changes and there it is possible that there is expected change in earth’s carbon dioxide in the next century period (Soon, 2007, p. 108). The shortcoming to this approach has been that, climate changes show that there are other forces of climatic changes happening simultaneously with carbon gas changes. These factors may cause global warming that synergizing the warming effect of carbon dioxide. Therefore, the sensitivity to the gas will be seen as greater than it really is. Sometimes these factors could reduce the effect cancelling out the impact of the CO2 gas making the sensitivity seem lower than it actually is (Caillon, et al, 2003, p.1731). In Ordovician time CO2 was 10 present concentration, which means temperature should have been about 8°C higher than present as per IPCC estimate
Conclusions
It is logical to agree that human activities have seen the increased in CO2
activities. However, the emissions are minimal, natural carbon sinks, and forests can balance them. Besides, the earth’s history has recorded higher temperature rises even before the industrial revolution a period that marks the heightening of human activities that cause CO2 emission. In most cases, the global climatic changes are because of variation in sunlight, this variation increase and reduce the amount of solar energy that warms the earth. To sum up, the natural causes of climate changes are often
overlooked by mainstream science and organizations since they are concerned with promoting the investment by governments in their researches than addressing human accusation.
Reference List
Caillon, N., et al. (2003). Timing of Atmospheric CO2 and Antarctic Temperature Changes across Termination III, Science, 299, p. 1728
http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf [accessed 14 March 2012]
Chylek, P., et al., 2009. Arctic Air Temperature Change Amplification and the Atlantic Multidecadal Oscillation, Geophysical Research Letters, 36: 10
Solomon, S., et al., 2010. Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming, Science, 327, 1219-1223
Soon, W & Baliunas, S. (2003). Proxy Climatic and Environmental Changes of the Past 100 years. Climatic research. Vol. 23, p. 89-110
Soon, W. (2007). Implications of the secondary role of carbon dioxide and methane forcing in climate change: Past, present and future. Physical Geography, vol. 28, 97-125
Spencer, R. 2008. Global Warming as a Natural Response to Cloud Changes
Associated with the Pacific Decadal Oscillation (PDO), www.drroyspencer.com, [accessed 14 March 2012]
Watts, A. (2009). Is the US Surface Temperature Record Reliable? www.heartland.org, [Accessed March, 2012]
