Global Climate Change Unit 2: The Atmosphere

The Greenhouse Effect What happens when you get in your car on a hot day? What would be the benefits of a greenhouse retaining heat? Sunlight penetrates atmosphere towards earth’s surface Some is absorbed at the surface, and some is reflected back to atmosphere Of that some is reflected back towards earth, and some escapes into space Gases that absorb and radiate heat are called greenhouse gases Water vapor, carbon dioxide, CFCs, methane, nitrous oxide The carpets and upholstery of the car absorb heat—the heat cannot get out.

Carbon Dioxide in the Atmosphere In 1958, Charles Keeling installed an instrument on top of the Mauna Loa volcano to measure Carbon Dioxide Why does it need to be on top of a volcano? Varies with the seasons as well (observe on graph) So how does this affect temperature? Greenhouse gases absorb heat and keep the temperature on earth warmer. Modeling – scientists write equations and enter data for variables to predict how factors like temperature and sea level will be affected Levels are variable other places (near forests)

Consequences of a Warmer Earth Effects will not be the same everywhere Melting of sea ice causes sea levels to rise Wetlands could be flooded, people could lose their homes, beaches could be eroded, salinity of water could increase! Hurricanes and typhoons become more common In Britain over 200 species of plants are blooming 55 days earlier than they did just 40 years ago!

Consequences Continued Gulf stream could be cut off – affect weather Increase in heat-related deaths People allergic to pollen would be at risk for longer Birds are nesting earlier, flowers are blooming earlier Mosquitoes are enabled – higher risk for malaria Droughts become more frequent Range of plants/animals change – increased competition and invasive species

Recent Findings and Reducing the Risk IPCC – 2500 of world’s leading climatologists from 70 countries Release regular reports (0.6 degrees Celsius in 20th century) Kyoto Protocol – 1997, representatives from 160 countries met and set timetables for reducing emissions In 2001 the U.S. decided NOT to ratify the Kyoto Protocol Examples: reforestation project Complicated by economic, political, and social factors International Panel on Climate Change most recent report: https://www.theguardian.com/environment/2018/oct/08/global-warming-must-not-exceed-15c-warns-landmark-un-report Click on link to show what we can do!