On Tuesday, October 23rd, 2018, Michael Mann came and spoke to the Science in Our World: Certainty and Controversy class. He is a Professor of Atmospheric Science at Penn State, with additional appointments in the Department of Geosciences and the Earth and Environmental Systems Institute. During his lecture, he discussed the impacts that climate change can have on this world.

Mann said that the “greenhouse effect” has been known for two centuries. Scientists from Joseph Fourier in 1827 to Guy Callendar in 1939 all realized the effects that these greenhouse gases bring to our environment. This is dealing with how greenhouse gases are polluting the environment. Although the greenhouse gases aren’t the only factor in the cause of climate change, it definitely plays a very large role. Along with the greenhouse gases, the environment is struggling due to the burning of fossil fuels. Additionally, humans aren’t helping out that much either.

Additionally, he informed my classmates and me that the average concentration of carbon dioxide in the atmosphere of the world has reached 410 parts per a million. The normal concentration is between 170 ppm and 280 ppm. Some scientists believe that we can hit 550 ppm by the end of this century. According to Scientific American, “‘The rate of increase will go down when emissions decrease,’ Pieter Tans, an atmospheric scientist at the National Oceanic and Atmospheric Administration, said.”

This clearly is a scary statistic, and after during more research, it gets even worse. According to Business Insider, “Research indicates that if unchecked, increased CO2 levels could cause pollution-related deaths to increase by tens of thousands, and lead to the slowing of human cognition (especially when you take into account the fact that CO2 levels tend to be higher indoors in cities). Carbon dioxide also contributes to warming that causes sea-level rise, searing heat waves, and superstorms.”

People’s lives are on the line for many reasons because of this problem. The rising levels of CO2 can affect peoples health by increasing the temperature of the world. It will allow people to die from heat waves, spreading of diseases, and extreme natural disasters. Although, CO2 alone won’t hurt human health at these levels. However, it will lead to more pollution in the ozone. A 2008 study stated, “that for every degree Celsius the temperature rises because of CO2 levels, ozone pollution can be expected to kill an additional 22,000 people via respiratory illness, asthma, and emphysema.”

Another important thing Mann demonstrated to the audience was his hockey stick graph. The graph was presenting the proxy reconstructions of past climate. It’s mainly showing the mean temperatures. In 1998, when Mann and other scientist were shown the data, they quickly realized that it looked like a hockey stick. An article in the Atlantic explained, “The graph depicting this result looked rather like a hockey stick: After a long period of relatively minor temperature variations (the ‘shaft’), it showed a sharp mercury upswing during the last century or so (‘the blade’).” Michael Mann then went to write a book about his findings called The Hockey Stick and The Climate Wars. This graph will continue to be climate science’s icon.