In general, global warming happens when the earth’s surface temperature rises. Scientists have emphasized that the warming of the earth is a natural process. Greenhouse gases are vital in maintaining an optimal temperature for the survival of all living organisms (Spencer, 2007). While it is true that such warming is important, excessive greenhouse gases may result to substantial increase in temperature (Spencer, 2007). Such increase in temperature may have dire consequences to the planet.
Some Aspects of Natural and Anthropogenic Climate Change
Natural climate change occurs as a result of physical earth processes such as volcanic eruptions. Major volcanic eruptions release tons of gases and particulate matters in the atmosphere. Volcanic eruptions warms the stratosphere and as a result produces a climate forcing where there is a cooling effect on the earth’s surface temperature. Mount Pinatubo in the Philippines for instance has produced a major impact on the world’s climate. Solar perturbation in the overall surface-atmosphere radiative heat balance surpasses the infrared trapping effect. Troposphere influences the stratosphere’s radiative forcing because of the dependence of reflected solar and upward long wave radiation on cloudiness. In the absence of volcanic aerosols the temperature of the stratosphere significantly increased by 3 K as opposed to the previous temperature measured 1 K in the presence of volcanic aerosols (Ramachandran et al., 2000).
Anthropogenic climate change involves the contribution of human activities in modifying the earth’s climate. Human-induced climate change has been largely accounted to increase air pollution and changes in land use. Among the pollutants released in the atmosphere which influences climate forcing include particulate matter, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead (US EPA, 2012). The Carbon Dioxide Information Analysis Center (CDIAC) estimated that 30.2 billion tonnes of carbon dioxide in 2006 excluding changes in land use has been released to the atmosphere having a degree of 6-10% uncertainty. Calculations of NOAA on the target greenhouse gas methane in cities, power plants and agricultural fields suggest that the actual value is probably one-third higher than the recommended calculations of the Intergovernmental Panel on Climate Change. Carbon dioxide concentration in the atmosphere is undeniably the most commonly estimated greenhouse gas to explain climate dynamics (Tollefson, 2010).
Screen and Simmonds (2012) reported that there has been amplification in the near-surface air temperatures of the Arctic region. Such increase in near-surface temperature has been almost twice as large as the global average in the last decades. The increase in concentrations of greenhouse gases has been seen as the culprit. Arctic warming has been found strongest during most of the years showing consistent reductions in sea ice cover. The observed increase in water vapor has been seen as a response to reduce sea ice cover and this may have enhanced warming in the lower part of the atmosphere during summer and early autumn. Strong positive ice-temperature feedbacks in the Arctic is also an indication of further rapid warming and sea ice loss which also is associated to ice-sheet mass balance and anthropogenic activities in the Arctic.
Mitigation
There has been a growing body of literature on strategies to mitigate human-induced climate change. In agriculture for instance, mitigation options varies with respect to practices that: (1) increase carbon stocks above and below ground; (2) reduce direct agricultural emissions during production; and (3) prevent deforestation and degradation of high-carbon ecosystems. But these mitigation plans come with tradeoffs. The goal is to minimize or if possible avoid potential tradeoffs using integrated landscape level planning. Carbon sequestration in forest plantations can minimize potential impacts on water and biodiversity through establishing diverse, multispecies plantations of native species. This goes along with the lower use of heavy machinery and pesticides in plantation establishment and management and locating plantation on degraded lands (Harvey et al., 2013).
Recent interest in carbon taxes to curb climate change has been presented to the public. Davis and Kilian (2011) estimated that gasoline tax increase has only a short-run impact on carbon emission. Some of the possible responses to increased gasoline tax include migration to areas proximal to work or changing jobs to work closer at home. People may opt to build a better mass transit system and more energy efficient vehicle. However, technological innovation of energy efficient vehicles may seem too far from the enactment of higher carbon tax. The introduction of electric cars to curb carbon emissions still remains questionable because the source of electricity to power cars for instance might create a larger carbon emission.
Conclusion
Because science in climate change is still young it is difficult to distinguish human-induced climate change which is linked with carbon emissions from natural climate change. The science behind this aspect needs “an integrated research efforts that rely on climate modeling and paleoclimate reconstructions based on data from analyses of tree rings, ice cores, marine and terrestrial sediments, glaciers and instrumental records” (USGS, 2013). There is however a general consensus among scientists that climate trends during the last century cannot be accounted to natural climate processes alone. And so, these trends in climate may be influence by humans as well. As a response, several mitigation options have been offered. However, tradeoffs must be considered in planning or before enacting a law. Regardless of findings on the possibility of anthropogenic influence to climate change it must be also taken into consideration that curbing air pollution and other causes on environmental degradation is necessary so that natural resources can be sustained over time.
References
Davis, L. W. and Kilian, L. (2011). Estimating the Effect of a Gasoline Tax on Carbon Emissions. Journal of Applied Econometrics, 26: 1187-1214.
Harvey, C.A., Chaco´n, M., Donatti, C. I., Garen, E., Hannah, L. et al. (2013). Climate-smart Landscapes: Opportunities and Challenges for Integrating Adaptation and Mitigation in Tropical Agriculture. Review. Conservation Letters, 00:1–14.
Ramachandran, S., Ramaswarny, V., Stenchikov, G. L. and Robock, A. (2000). Radiative Impact of the Mount Pinatubo Volcanic Eruption: Lower Stratospheric Response. Journal of Geophysical Research, 105 (D19):409-429.
Screen, J. and Simmonds, I. (2010). The Central Role of Diminishing Sea Ice in Recent Arctic Temperature Amplification. Nature, 464: 1334-1337.
Spencer, Roy W. (2007). How Serious is the Global Warming Threat. Social Science and Public Policy, 44: 45-50.
Tollefson, J. (5 May 2010). Greenhouse-gas Numbers Up in the Air. News. Nature, 465: 18-19, doi:10.1038/465018a.
U.S. Environmental Protection Agency. (21 April 2012). Six Common Air Pollutants.Retrieved from: http://www.epa.gov/air/urbanair/.
U.S. Geological Survey. (24 January 2013). Distinguishing Natural Climate Variability from Anthropogenic Climate Change. Retrieved from: http://www.usgs.gov/climate_landuse/clu_rd/pt_nat_climate.asp.
