Write 5 pages with APA style on The Hockey Stick Controversy and the Legitimacy of IPCC’s : Human Impact on Climate Change. These arguments have been taken up by the fossil fuel industry and have been funded by lobby groups that attempt to cast doubt on climate science. The controversy became prominent in the 1990s when a group of scientists who used proxy indicators to indicate temperature records in the previous centuries found different reasons that caused global warming and argued them differently (Jolis, 2012). A group of scientists such as Michael E. Mann, Raymond S. Bradley, and Malcolm K. raised some of those controversies by using statistical analysis of an assortment of proxies to come up with the first quantifiable hemispheric-scale reconstruction presenting global configurations of annual surface temperature. The graph shows temperatures that date back to 1400 whereby they shaded the areas to show emphasis on uncertainties whereby the two standard error limits were larger than in earlier centuries. The above group of scientists published a paper in 1999 that traced back climatic changes for the previous 1000 years using an extended graph that showed a descending tendency in proxy temperatures from a medieval warm period trailed by a 20th-century escalation and a steep upsurge in measured temperatures since the 1950s. According to the United Nations Intergovernmental Panel on Climate Change (IPCC) and Third Assessment Report (TAR), the year 1998, was the warmest year in the northern hemisphere for the last 1000 years. The above organizations used the controversial hockey stick graphs to publicize the featured information. The information became a focus for dispute for the people who were contrasting to the strengthening scientific agreement that late 20th-century warmness was unique. Some of the scientists who were opposed to these changes were Willie Soon and Sallie Baliunas. However, scientists later dismissed their publication as deeply flawed (McKitrick, 2010).
I also disagree with the legitimacy of the previous research used by the United Nations Intergovernmental Panel on Climate Change (IPCC) since their research shows less dramatic results if techniques that are more reliable had been used to analyze the data. Later researches have shown that an increase in greenhouse gases due to human activity is a prime cause of global warming.