The green house effect traps heat in the atmosphere and radiates the heat back toward the earth, ultimately warming it. Methane, carbon dioxide, nitrous oxide, and chlorofluorocarbons are all gasses that are part and contribute to the greenhouse effect. However, humans have interrupted the natural greenhouse effect. We burn a lot of fossil fuels which increase the concentration of carbon dioxide. Clearing land for human activities, such as agriculture and industry, also increase the concentrations of greenhouse gases. When we release more gases, we are slowly making the earth warmer. Some regions will respond well to the warmer conditions, but some will not. Some regions will also become wetter or dryer, because there will be more evaporation and precipitation. However, because of warmer temperatures glaciers will melt and the oceans will warm. The oceans could also expand, which would cause the sea level to rise. Humans have clearly affected the greenhouse effect. Because of industrial activities, in he last 150 years, we have raised the atmospheric carbon dioxide level s from 280 parts per million to 400 parts per million. According to NASA's article called A Blanket Around the Earth,"there's a better than 90 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in Earth's temperatures over the past 50 years." This provides evidence that suggest that humans are affecting the temperature of the Earth.
Source: http://climate.nasa.gov/causes/

Lauren, I really enjoyed your analysis of Global Warming and what is causing it. It seems as though you really researched the topic and considered all possible causes and affects of global warming, which were all very interesting. I agree with your stance that humans are undoubtedly responsible for the recent rise in climate change, do to all of our productions, transportations, and uses. However, in order to inform myself more on the argument against human involvement in global warming, I went to the website, http://climatechange.procon.org/view.re … eID=006525. These people argue that the human-generated emissions are too small to actually make an affect on the environment. For instance, the atmosphere can absorb the gases that we emit. They also claim that the recent warming of the climate is due to natural processes like changes in the sun's heat and ocean currents. Although I still agree with your view that humans are responsible for the large increase in the Earth's temperature, I can understand how some people disagree with that. Regardless, I belie ve it is important for all people to do whatever they can to limit their impact on the environment, because every change makes can make a difference.

At our school we did an experiment in which we studied the greenhouse effect and how the greenhouse gasses impacts to the temperature. The most frequent greenhouse gas is actually the steam, BUT if there's a lot of carbon dioxide then there's a lot of more steam and so the temperature on Earth grows. We cannot impact on the steam, but we can reduce the carbon dioxide emissions as we ride a bike, walk or travel by public transport more, reduce the use of plastic etc. But we must start to make changes today, because every change, even a small one, is important.

I have watched a documentary about greenhouse effects and climate changes. The title of the documentary is: An Inconvenient Truth. I suggest you to watch it, because it nicely show how the global warming is destroying our ONLY home - THE  EARTH.