What is the relationship between increasing amounts of greenhouse gases and global climate change?
As we know, greenhouse gases are beneficial to life on earth and have been established as a very important function in our atmosphere. The Woods Hole Research Center http://www.whrc.org/resources/primer_greenhouse.html makes the comparison of greenhouse gases to a blanket that insulates the heat from our bodies and traps it in keeping us warm during a cold winter night; greenhouse gases work in a very similar fashion. These particular gas molecules in the air trap infrared radiation from the earth originally heated up by the sun. According to the NASA climate change webpage http://climate.nasa.gov/causes/ the most common greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide and CFC's (clorofluorocarbons). Unfortunately greenhouse gases can be a double-edged sword in the sense that while they provide us with a way to trap the sun's heat for warmth when the gases become more excessive there is a thickening of the atmosphere. Referring back to the "blanket" metaphor, the end result is that now we are experiencing an atmosphere that is beginning to feel more like having 3 or 4 full quilts.
While man-made factories, automobiles and other pollutants are displacing unnecessary amounts of these greenhouse gases in our atmosphere our planet is feeling the effects. The most commonly known is the warming of the atmospheric temperatures and oceanic temperatures. This leads to increasingly high temperatures during summer time, more glacial melting and sea level rising. Increased warm air and moisture are key ingredients for more frequent and larger hurricanes and other tropical storms. The excess heat is also responsible for some areas to become more dry than they previously were, and some areas to precipitate more due to more water vaporization. Also, ecosystems are being disturbed by the early warming after winter, as well as agriculture being impacted by heat waves, floods, droughts and displacement of foreign consumers due to shifts in nearby ecosystems.
Imperfect understanding of climate feedback is a major cause of uncertainty and concern about global warming. How can the use of climate models help in the understanding of these uncertainties?
Climate models are a very useful tool in helping climatologists and other scientists in making predictions for climate patterns, and possible outcomes given certain variables. According to the Windows 2 the Universe webpage http://www.windows2universe.org/earth/climate/cli_models4.html the basic format for climate models is a trial-and-error process of applying certain mathematical equations in a simulation and determining how they fair against actual recorded data. When there is no significant difference in the data, the scientists will then use that mathematical formula for future predictions. This is constantly done to ensure quality and accuracy of the information being provided for data analysis. There are some uncertainties with climate-related data due to the amount of feedbacks and forcings found within a climate area as well as the fact that not all of the systems within a climate are 100% understood by science today. This is why it is so critical for research to continue to gather information in order to provide the most accurate climate models. Not only are they important for our understanding of what our impact as a human race has been on the planet, but also predicting what it can be.
With regards to the six emission scenarios, describe any evidence existing today that would suggest to you one or more of the scenarios may occur within the next 100 years. What key uncertainties (climate forcings and feedbacks) would exist for these scenarios as a whole, or specific ones individually?
The Intergovernmental Panel on Climate Change (IPCC) emission scenarios give about as accurate of predictions as there can be considering the model is based on our future in 100 years. When you observe the chart on "Global Carbon Dioxide Emissions" it is very apparent which scenarios would be most and least favorable. A1F1 and A2 are the riskiest scenarios for our environment, and unfortunately the more likely to occur. Our dependence on fossil fuels has only recently begun to see even the slightest bit of attention after the highest gas prices in our nation's history, the political ties with a war fought on foreign soil and the last few decades having record heat waves and tropical storms. There have been certain steps in the right direction such as the development of hybrid and electric cars and research/funding going toward alternative energy sources (photovoltaic cells, wind turbines, etc). The ecological problems our planet faces may likely remain being second seat to the economical problems since those with the power to pass legislation tend to be more focused on the latter issue; the one that most directly affects their pocketbooks. Unless our country, and others begin to really invest and make a conscious decision that fossil fuels need to be used as minimally as possible and alternative energy sources needs to take precedence we are definitely looking at one of the mentioned scenarios. The other scenarios are definitely possible, but will take a long time for us to really see the long-term effects. It is very difficult for people today to make sacrifices and take actions that will be taking place long after their time is passed. People (especially in the US) want results immediately, and tend to lack patience. This can truly be a virtue that saves our planet or we can let the vice of greed take our planet to the point of no return when repair is impossible and our situation worsens.
