Extra Credit #3 Movie Discussion Board: Global Dimming

When we see the increase in global temperatures, there is always that conspicuous absence of warming from 1940s – 1970s. Since there is no correlation with CO2 during this period, some climate deniers use these data to refute the impact of CO2 on the global temperature. Temperature.png However, many factors affect warming, including changes in incoming solar radiation and the reflective properties of sulfate aerosols that are released with the burning of fossil fuels. Only when combining all these factors together can we account for the rise in global temperature across all the different decades – and even the lack of warming in the mid-20th century. This movie provides a detailed explanation as to how the release of sulfate aerosols led to reduced incoming solar radiation that ironically kept the globe from warming. It wasn’t until the clean air act in 1970 that global warming resumed. Even today, it is not clear how much the current pollutant haze may be offsetting the total warming that would ensue in the absence of air pollution. Hence, we need to tackle both the release of CO2 resulting in global warming and the pollutant emissions – both factors that result from the burning of fossil fuels. For this Movie Discussion Board essay/blog, please watch the movie Global Diming, and combine what you learn from this movie with the arguments at skeptical science.com: https://www.skepticalscience.com/global-cooling-mid-20th-century-advanced.htmLinks to an external site. as to why there was no mid-20th Century warming. Make sure to: Describe four data sets from the movie that led scientists to learn about global dimming,and explain how the Clean Air Act helped to eliminate this dimming. (5 points) Explain how current pollution emissions and airplane contrails may still be an important factor minimizing the total warming that could already have happened. (5 points) Explain which aspects of the global radiation budget are affected by sulfate aerosols and CO2. Do sulfate aerosols prevent the loss of outgoing infrared radiation? Does CO2 minimize incoming solar radiation? Or is it the other way around? (5 points) Also remember to make your essay/blog personal: Spice it up with the three things that struck you the most while watching the film (3 points). And remember to read and comment on others posts. (2 points) Follow the Discussion Board Rubric in the gear box on the upper right to make sure you get all points. We are looking forward to seeing how you piece this all together!