ANTH 1010 Lecture Notes - Lecture 9: James Hansen, Greenhouse Effect, Sea Level Rise
Document Summary
Evidence supporting the notion that global warming is caused by humans. #1 - fossil fuel signature in the air. Plants prefer carbon 12 vs carbon 13. Fossil fuels are called fossils because they are the product of deterioration of ancient plants. If we are impacting the carbon in the air through fossil fuel burning, it would be carbon. 12 that would be building in the atmosphere. This is exactly what we see when looking at breakdown of chemical composition in atmosphere. #2 - less heat is escaping out to space. Satellites measure ir radiation as it escapes into space. A comparison between satellite data from the period 1970 - 1996 found that even less energy is escaping at the wavelengths that ghg absorb energy. Direct experimental evidence for a significant increase in the earth"s gh effect . Confirmed by lots of different measurements and satellites. World"s oceans have been building up heat noticeably over the last 40 years.
