Greenhouse Effect and Climate Change, Article Review Example

Abstract

An increase in greenhouse gases in the atmosphere has occurred resulting to changes in the Earth’s weather and climate. Carbon Dioxide (CO₂) is the major greenhouse gas that is emitted into the atmosphere. There are several other gases that affect climate and will continue to affect the climate for decades after being emitted into the atmosphere such as, methane (CH₄), nitrous oxide (N₂O), ozone-depleting substances (ODSs), hydro fluorocarbons (HFCs), sulfur hexafluoride (SF₆), and perfluorocarbons (PFCs). Scientific data suggests that in order to maintain global average temperatures, the temperature must be limited to 2 °C above the pre-industrial average temperatures. Since the year 2000, it has been estimated that 466 billion tons of CO2 was emitted due to human activities, including deforestation. In addition, it was estimated that non-CO₂ gases were comparable in emission numbers to CO₂ emission number from fossil fuel combustion during the 1980s. Due to the effects of greenhouse gases, research into renewable energy sources has been developed. Types of alternative energy sources are known as natural, wind, solar, hydro and biomass. Although these sources offer an alternative to greenhouse gas emissions, further research and strategies to prevent environmental impact should be investigated.

Key Words: Greenhouse gases, global warming, CO₂ emissions, alternative energy sources

Introduction

The sun is the driving force for the Earth’s climate and weather. The Earth absorbs energy from the sun and radiates the remaining energy back toward space; however, some of the gases in the atmosphere, known as greenhouse gases, trap the radiated energy and keep the energy in the atmosphere. The greenhouse gases and energy then form a “blanket” in the earth’s atmosphere causing an increase in the Earth’s surface temperature. This phenomenon is known as the “greenhouse effect” and occurs naturally; however, due to human activities during the past century, an increase in greenhouse gases in the atmosphere has occurred resulting to changes in the Earth’s weather and climate. (EPA, 2012) Carbon Dioxide (CO₂) is the major greenhouse gas that is emitted into the atmosphere through anthropogenic processes, but there are several other gases that affect climate and will continue to affect the climate for decades after being emitted into the atmosphere such as, methane (CH₄), nitrous oxide (N₂O), ozone-depleting substances (ODSs), hydro fluorocarbons (HFCs), sulfur hexafluoride (SF₆), and perfluorocarbons (PFCs). The use of these gases is essential to society’s needs for both food and energy; therefore, their continued use will continue to increase the Earth’s climate. (Montzka et al., 2011). In order to prevent climate changes, alternative energy uses are being implemented. The current paper reviews the sources for greenhouse gas emissions, as well as the approaches underway with alternative energy solutions.

Carbon Dioxide (CO₂) Emissions

Carbon dioxide emissions occur from fossil-fuel combustion and other industrial and non-industrial sources, such as deforestation, logging, post-burn decay of above ground biomass, decomposition of organic carbon in peat soils, and forest and peat fires. In addition, carbon dioxide is the main cause of global warming. In the year 2012, however, the global CO2 emissions increased by only 1.1%, compared to an average annual increase of 2.9% observed over the last decade. A study has computed the six largest emitting countries in 2012. The largest was China at 29%, United States at 15%, the European Union at 11%, India at 6%, Russian Federation at 5% and Japan at 4%. (Figure 1) In China and United States, the yearly increases were less than average carbon dioxide increases observed in the past decade. (PBL, 2013) This is indicated as due to a decrease in electricity and fuel need from basic materials and the increase in the use of renewable energy sources and implementation of energy efficiency programs. (IEA, 2013) In addition, the United States starting shifting from coal to natural gas for power generation and reduced coal consumption by 12% in 2012. Furthermore, the implementation of wind and bioenergy decreased carbon dioxide emissions by 4%. (PBL, 2013)

Scientific data suggests that in order to maintain global average temperatures, the temperature must be limited to 2 °C above the pre-industrial average temperatures. The United Nations established this number in the UN climate negotiations and has indicated that the target is possible if the CO2 emissions do not go over 1,500 billion tons. (Meinshausen et al. 2009) Since the year 2000, it has been estimated that 466 billion tons of CO2 was emitted due to human activities, including deforestation. (PBL, 2012)

Non-CO₂ Gases

The effect of non-CO₂ greenhouse gases on global warming has also been explored. In fact, it was estimated that non-CO₂ gases were comparable in emission numbers to CO₂ emission number from fossil fuel combustion during the 1980s. (Figure 2) As seen in Figure 2, studies have calculated the total emissions of non-CO₂ greenhouse gases to decrease to 15 GtCO₂-eq yr. It has been indicated that this reduction is due to a protocol that was implemented, known as the Montreal protocol, which has reduced the use of ozone depleting substances. Mitigation strategies have been implemented in order to quantify the amount of emissions and their changes in emission to specific sources or processes, such as natural or anthropogenic. The estimations are reported to the United Nations Framework Convention on Climate Change and are estimated based on inventory of emissive processes; therefore, there are difficulties in estimating or quantifying exact numbers. Overall, the current approaches are estimations and not factual numbers of emission gases and are based on top-down approaches. In addition, significant discrepancies have been noted between these methods. However, there are currently new methods underway due to advances in technologies and high-resolution transport models that might provide a better estimate. (Monztka et al., 2011)

Methane (CH₄) is a type of non-CO2 greenhouse gas that has been indicated to have both anthropogenic and natural emissions that can increase with global population increases and as the climate warms. Estimations from inventory based calculations have shown a significant increase in human-derived CH4 from the years 2000 to 2005. The increase is suggested due to a rapid increase in economic growth and increased demand for energy in Asia. (European Commission Joint Research Centre, 2010) In addition, Nitrous Oxide has also shown an impact as a greenhouse gas. In fact, the N2O concentration in the atmosphere is 19% higher than in pre-industrial times. The increase is suggested due to the use of inorganic fertilizers, nitrogen-fixing crops and deposition from combustion of fossil fuels. Therefore, N₂O concentrations are increasing through natural and human activities. (Galloway, 2008)

Although CH₄ and N₂O have significant natural sources, there are many gases that have no significant natural sources and the total emissions of from human activities. These ozone depleting sources are chemical compounds such as, Chlorofluorocarbons, carbon tetrachloride, methyl chloroform, methyl bromide and halons). Although these gases have decreased in emissions since the 1990s, the substitute chemicals that have been implemented due to the protocol on these greenhouse gases are also showing a potential as a greenhouse gas. For instance, non-ozone depleting HFCs that were implemented for use in replace of ozone depleting gases are showing an increase in global concentration and are showing signs acting as a greenhouse gas. (Montzka et al., 2008)

Alternative Energy Sources

Renewable Energy sources are energy technologies that convert renewable resources into energy that replaces the conventional methods, such as fossil fuels. Types of alternative energy sources are known as natural, wind, solar, hydro and biomass. The Natural Energy Technology Laboratory (NETL) evaluates the roles of different energy sources based on the resource, growth, costs, barrier, environmental characteristics, risks, and expert scientific opinions. (Table 1) For instance, the U.S Department of Energy has researched for the use of natural gas. It has been found that natural gas is a cleaner burning type of gas compared to other fossil fuels and it can be used in different applications, such as residential, industrial and transportation. (U.S. Department of Energy, 2012) In addition, wind turbines have been constructed to capture wind energy and convert the energy to electricity. The benefit of wind systems is that the wind system can be small, stand alone, or be connected to a huge power grid. Furthermore, solar heating and electricity systems have been developed as an alternative source using passive solar, active solar and photovoltaic systems. The downfall to both wind and solar systems is that there is a need for wind and the sun to occur naturally in order to produce energy. There are other forms of renewable energy sources such as hydroelectric power and biomass. Hydroelectric technologies use water to produce energy. Most of the hydroelectric systems use streams that direct water through a turbine. Biomass resources use plant-derived organic material to produce energy through burning for heat, electricity and conversion to liquid or gas fuels. (Alberta Environmentally Sustainable Council, 2001)

Conclusion

Greenhouse gases have been shown to have a negative effect on the greenhouse effect and have been correlated to the increase in the global average temperature, as well as climate changes. There are several options available in order to decrease the emissions of greenhouse gases, such as renewable energy systems. Although there are benefits to renewable energy in regard to global warming, the transition to a larger scale use of this type of energy does present some problems. Renewable energy requires large amounts of land. For instance, the installation of wind and solar technologies need to acquire land and compete with other industries. In addition, there are environmental issues, such as killing of wildlife, especially in regard to wind energy. Therefore, research should focus on the benefits world-wide and solutions to decreasing the environmental impact of renewable resources. For a start, the Federal governmental and State governments have implemented procedures for regulating environmental impacts to ecology caused by renewable resources. (National Research Council, 2007)

Figure 1. Global CO2 emissions in different regions from fossil-fuel use and cement production. (PBL, 2013)

Figure 2. Emissions of non-CO2 and CO2 greenhouse gases.

(U.S Department of Energy, 2012)

References

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