The Factors Responsible for Climate Change: Natural Or Anthropogenic

Climate change often interchanged with the term global warming, maybe defined as the long-term change in the average weather patterns of earth’s local, regional and global climates (NASA, 2021). Over the last hundreds of years and even in recent times climate change have become a concerning factor. According to NASA (2021), climate change started increasing during the pre-industrial period (1850-1900) and Earth’s global average temperature have increased by approximately 1.8 oC and have seen to be increasing by 0.2 oC per decade. It is believed that for the last hundred of years climate change was caused predominantly by natural forcing factors, however, with other contributing factors such as anthropogenic factors and factors affecting Earth’s energy budget this cannot be true. Although natural forcing factors play an important role in influencing climate change other factors such as those affecting the earth’s energy budget and anthropogenic factors which may even outweigh natural forcing factors, also contribute to the ongoing effects of climate change. So we have a question without answer 'are humans responsible for climate change?'.

The pages of this essay will critically evaluate the statement “The last hundred years of climate change was caused predominantly by natural forcing factors” by exploring natural forcing factors such as changes in the sun output and earth orbital cycle, explosive volcanic eruptions and ocean currents; Anthropogenic factors such as the burning of fossil fuels, deforestation and exhaust from vehicles and aerosol spray and factors affecting earth’s energy budget.

Natural processes are inevitable and cannot be altered or interfered with by man as such natural forcing factor are a great contributor to climate change over the last hundred of years. Natural forcing may be external (sun output, earth’s orbital cycle, volcanic eruptions) and internal (ocean currents). The sun is the major source of energy on Earth and is responsible for the biological and physical processes that takes place around us as such the rate of energy produced from the sun on a day-to-day basis can affect the climate and long-term changes. The orbital pattern or cycle of the sun influences the geographical distribution of its energy over the surface of the earth and as such can affect climate directly, through the heating of earth and the atmosphere as well as indirectly through cloud-forming processes (Union of concerned scientists, 2009). Union of concerned scientists (2009) continued by saying ultraviolet rays, the highest wavelength of energy from the sun, has the ability to modify ozone concentrations in the level of the atmosphere where weather is concerned affecting cloud formation and temperature; additionally, changes in solar energy can change the flow of cosmic rays causing the formation of more ions and modifying cloud formation resulting in changes in temperatures and weather patterns. According to Columbia University (2018), with use of ancient rocks from the Arizona desert scientists have uncovered an orbital trend of earth that repeats every 405,000 years and is believed to have influence climate change, that is, the sun’s orbital patterns change from circular to slightly elliptical and back to circular every 405,000 years. This change in the shape of earth’s orbit along with the tilt of Earth’s axis changes the amount of solar energy that gets to the northern hemisphere, or each hemisphere in general, causing a long-term change in climate in these areas. Scientist believes that this changes in Earth’s orbital cycle has greatly contributed to periods of cooling and warming over the last millions of years (Columbia university, 2018). Volcanic eruptions are also another natural forcing contributing to climate change, ash and dust particles thrown in the atmosphere from explosive volcanic activity can result in cooling as these particles block incoming solar rays. Volcanic activity can also result in warming as during eruptions excess amount of gases are emitted contributing and resulting in global warming. An example of this is the eruption of la Soufriere in St. Vincent, the effects of this eruption can result in climate changes lasting from month to years. Ocean currents, specifically El Nino is another natural contributing factor to climate change. El Nino according to NASA (2009) is an abnormal warming of the surface of ocean waters located in the eastern tropical Pacific which occurs every 3 to 8 years and can result in the changing of climate; for example, an unusually strong occurrence of El Nino took place between the years 1997 and 1998 which resulted in 1998 to be one of the hottest year recorded.

Although these natural forcing factors all contribute to climate change, on their own they are too small in impact to be predominantly responsible for climate change. Contributing anthropogenic factors in conjunction to these natural factors may prove to be more likely to be responsible for climate change over the past hundred years. As the population increases so the does the rate of global warming and climate change this is evident as the atmospheric concentration of gases such as Methane, Carbon-dioxide and Nitrous oxide have all increased since the year 1750 due to anthropogenic causes (IPCC, 2013). This then means that human/anthropogenic factors play a vital role in climate change. The burning of fossil fuels is one of the leading causes of global warming and climate change as this process releases an excessive amount of heat-trapping gases in the atmosphere. According to IPCC (2013), the emission of Carbon-dioxide has increased by 40% since the pre-industrial period due to the burning of fossil fuels. The use of land space is also a contributing factor to climate change. Deforestation, the removal of trees, whether for the purpose of agriculture or the construction of building is resulting in the increase of carbon dioxide present in the air. Trees and other plant use carbon dioxide for the process of photosynthesis as such the presence of trees reduces carbon-dioxide hence, reducing or limiting climate change. In addition to this the clearing lands are used for the construction of homes and or businesses, as the population increases the demand for these two infrastructures increases; cement production (material used in building) is one of the major contributors to global warming as such even the simplest form of anthropogenic activity such as the building of houses and other infrastructures contributes to global warming. Another point in relation to population increase is also that this results in the increase of vehicle usage and aerosol sprays hence, once more increasing heat-trapping gases in the atmosphere and resulting in global warming and to a greater effect climate change. While natural forcing factors may follow a certain trend or cycle, anthropogenic factors are likely to drive climate change for years to come, as the population is growing the demand for certain things will increase as well as such these anthropogenic factors contributing to climate change will increase along with climate change and as such may even become the predominant contributor to climate change rather than natural forcing factors.

Last but not least, factors affecting earth’s energy budget, namely Radioactive forcing, is also a contributor to climate change. Radioactive forcing according to IPCC (2013) measures the change in energy fluxes for both natural and anthropogenic factors contributing to climate change as these factors would have affected earth’s energy budget and result to certain changes. A positive radioactive forcing suggests surface warming while a negative radioactive forcing suggests cooling surfaces. IPCC (2013) continued by saying that the total radioactive forcing has been positive since 1750 and is as a result of increased in atmospheric carbon-dioxide. Although radioactive forcing isn’t directly a contributing factor to climate change, it shows how impactful and contributive anthropogenic factors especially those resulting in the emission of carbon dioxide and other heat-trapping gas can be. Radioactive forcing shows that natural forcing factors are not and cannot be predominantly responsible for climate change over the past hundreds of years especially with statistics that shows that the total anthropogenic radioactive forcing has increased by 2.29W m-2 in 2011 compared to 1750 and was 43% higher in 2011 than in 2005, this shows that the total anthropogenic radioactive forcing is vastly increasing even more than that of natural forcing (IPCC, 2013).

In conclusion, natural forcing factors on their own cannot be predominantly responsible for climate over the past hundred years. The effect of these factors are to small to have resulted in such major climate changes over the years as such it is believed that both natural forcing factors and anthropogenic factors, collectively, influences/contributes or is the reason for climate change, in fact, anthropogenic factors may outweigh natural factors as the impact of these factors on climate change are seemingly increasing rapidly as the years go by.

References

1. Columbia University. (2018). Earth's orbital changes have influenced climate, life forms for at least 215 million years. Retrieved on 2nd of May 2021 from: https://phys.org/news/2018-05-ancient-scientists-climate-deep.html#:~:text=Kent and Olsen say that,is at its most circular.
2. IPCC. (2013). Summary for policy makers. Climate change, 3-29, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
3. NASA. (2021). Overview: Weather, Global Warming and Climate Change. Retrieved on the 2nd of May 2021 from: https://climate.nasa.gov/resources/global-warming-vs-climate-change/
4. NASA. (2009). The Ups and Downs of Global Warming. Retrieved on the 3rd of May 2021 from: https://www.nasa.gov/topics/earth/features/upsDownsGlobalWarming.html
5. Union of concerned scientist. (2009). How Does the Sun Affect Our Climate?. Retrieved on the 2nd of May 2021 from: https://www.ucsusa.org/resources/how-does-sun-affect-our-climate#:~:text=The Sun-climate connection,-The Sun is