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Climate Change ________________________________________ Ryan Tagher Jan. 17, 2017

Climate change is the observed change in Earth’s climate, specifically the gradual temperature increase in the late 20th into 21st century. In the IPCC’s (Intergovernmental Panel on Climate Change) fifth assessment report, they state that the warming observed after the 1950s is unmatched over thousands of years. Simultaneously, the oceans have risen at a higher rate than the rate over the previous two millennia. Some of the most likely causes are the rise in greenhouse gases in the atmosphere and an increase in the solar irradiance from the sun.

Climate Change Statistics ________________________________________ In the IPCC’s fifth assessment report, they state that each decade has been warmer than the one that preceded it and that the period from 1983-2012 was likely, with medium confidence, the warmest period the Earth had seen in the last 1400 years. Specifically, the average combined temperature increase of the land and the ocean between 1880-2012 was .85 ± .20 °C. The temperature increase specific to the oceans was .11 ± .02 °C between 1971 and 2010. This happened concurrently with the rise in sea level, which was .19 ± .02 meters between 1901-2010. Because of this warmth and rise of the oceans, the number of glaciers in the arctic has been decreasing as well. Between 1971-2009, the Arctic lost an average of 226 ± 135 glaciers per year, with that number rising to 275 ± 135 glaciers between 1993-2009. In a report by the Climate Interactive Scoreboard, without significant action on climate change, Earth’s temperature could rise as much 5 degrees Celsius (9 degrees Fahrenheit) in the next 100 years.

Causes of Climate Change ________________________________________ The biggest and most likely cause of global warming is the increase in greenhouse gases in the atmosphere. In pre-industrial times, the amount of CO2, the most important greenhouse gas, in the atmosphere was only about 280 ppm but that increased to about 379 ppm as of 2005. This is much more than the natural amount of 180-300 ppm measured in ice cores, making it very likely that humans have caused this increase. When fossil fuels are burned, they release CO2 into the atmosphere, which traps heat. The use of fossil fuels has increased over the last few decades and will likely continue to increase due to population growth.

Another potential cause for global warming is the increase in energy given off by the sun, or solar irradiance, which would cause the Earth to heat up naturally. According to the IPCC’s fourth assessment report, the increase in solar irradiance is very small, accounting for .12 W/m2 radioactive forcing, as compared to about 1.6 W/m2 radioactive forcing for greenhouse gases.

Efforts to Combat Climate Change ________________________________________ Because emissions are almost universally thought of to be the main cause of climate change, much of the efforts to combat it have been directed at reducing greenhouse gas emissions. One such action is the Kyoto Protocol, an international agreement adopted in 1997 that sets “internationally binding emission reduction targets”, according to the United Nations Framework Convention on Climate Change. This act mandates that developed countries reduce their carbon footprint much more than underdeveloped countries due to the significantly higher carbon footprint from the industrial activity of developed countries. According to the Council on Foreign Relations, this act has had some success, but has also been held back by too few commitments from a few specific countries. There are many countries who are on track to meet their targeted carbon footprint and some large countries like India, Brazil, and China have even taken on voluntary efforts to control their pollution. However, these mandates keep stirring political controversy, especially with the EU Airplane tax. When the Kyoto Protocol was set to expire in 2015, two of the largest carbon emitters, Canada and Japan, backed out of the agreement.

Outside of the Kyoto Protocol, the UN_REDD (United Nations Reducing Emissions from Deforestation and Degradation) provides financial incentives for poorer countries to protect their national forests. The Bali Action Plan provided a mechanism for enforcing emission curbs by making sure that the actions of countries can be measured, reported, and verified (MRV).

Citations ________________________________________ "Climate Change 2014: Synthesis Report: Summary for Policymakers." 539-64. IPCC. 2014. Web. 17 Jan. 2017. "Human and Natural Drivers of Climate Change." IPCC. N.p., 2007. Web. 17 Jan. 2017. "Climate Change 2007: Synthesis Report: Summary for Policymakers." 1-22. IPCC. 2007. Web. 17 Jan. 2017. "The Global Climate Change Regime." CFR.org. Council on Foreign Relations, 21 July 2012. Web. 22 Jan. 2017. United Nations Framework Convention on Climate Change. "Kyoto Protocol." United Nations Framework Convention on Climate Change. United Nations, 21 Dec. 2012. Web. 22 Jan. 2017.