At the end of class on Friday Mr Willard left us with 5 questions regarding global climate change. These questions were as follows:
1. Is the Earth warming?
2. If so, is this warming unnatural?
3. If it is unnatural, is it anthropogenic (human-caused)?
4. What might happen as a result of this climate change?
5. What can and should we do to fix this?
Then in class on Monday we discussed the views of the Intergovernmental Panel on Climate Change (IPCC) on this subject and tried to answer some of these questions. So is the Earth warming? According to the IPCC yes, the global average temperature has increased by 0.74 degrees Celsius, which is approximately1.3 degrees Fahrenheit, over the past 100 years. This may not seem like a drastic change but this number is only a global average. It is important to note that in some places the climate is changing very little and in other there is a much more rapid climate shift. For example arctic temperatures have risen twice as fast as the rest of the world over the past 50 years. Another fact that is evidence of global warming is the temperature records as of recent. Since 1861, when temperatures were first recorded, the 5 hottest year are record were 2005, 1998, 2002, 2003, and 2006.
Ok so there is definitely evidence supporting that the Earth is warming, but is this warming unnatural? According to the IPCC temperature and carbon dioxide levels in the troposphere are “beyond normal range” and paleoclimatic records show an “unnatural increase in temperature and carbon dioxide over the past 50 years”. This graph illustrates Carbon Dioxide levels in the atmosphere and Global Temperature over the past 1000 years.
The next question regarding global warming is, Is this unnatural climate change our fault? Once again the IPCC says that global climate change is indeed anthropogenic. Since the Industrial Revolution there has been a drastic increase in 3 of the 4 major greenhouse gases, and these are Carbon Dioxide (CO2), Nitrous Oxide (N2O), and Methane gas. All of these gases have increased due to human activity. The main causes of CO2 increase is the burning of fossil fuels and land use change. Land use change in this situation most directly means deforestation. Deforestation is a major problem because it destroys one of the planets natural carbon sinks. A carbon sink is is a place that stores carbon such as CO2. When you cut trees that usually store carbon more carbon in the form of CO2 is released into the atmosphere. Another acticity that we as humans do to cause an increase in greenhouse gases is agriculture, and this causes increases in methane and N2O levels in the atmosphere.