Carbon Dioxide

Climate Change Climate can be altered by several factors: – greenhouse gases (CURRENT) – THIS IS HUGE!! – Earth’s wobble on its axis – variations in the Sun’s output – volcanic eruptions CO 2 is the dominant greenhouse gas

Carbon Dioxide is produced by burning fossil fuels and biomass Oil Coal Natural Gas Wood and agricultural waste

SO......the sectors that produce the most CO 2 are: Generation of electricity Transportation

Current Observations [CO 2 ] in the atmophere is rising Average global temperatures are increasing Ice sheets are melting Spring is arriving sooner in the year Sea levels are rising Oceans are acidifying Species are being lost (extinction)

[CO 2 ] in Atmosphere is Increasing 8 From ice core data From measurements

Keeling Curve for CO2

Why does the Keeling Curve oscillate? Why is it not constant? The CO2 levels change seasonally. Land plants absorb CO2 in photosynthesis. There is more land in the Northern Hemisphere So, when the North is in summer, plants absorb more CO2 and the levels drop a bit.

12 Historical Relationship between CO 2 levels and global temperatures

13 Sea Ice is Decreasing Between 1979 and 2005, average Arctic sea ice dropped 20% (as shown in blue hues above) Decline of 4.7% per decade

14 Sea Levels are Rising If seas levels rise by 9-88cm during this century, most of the Maldives islands and their coral reefs will be flooded.

Ocean Acification - Coral pH 8.2, (by 2100) Great Barrier Reef (1500 miles long) Coral requires low [CO 2 ] so that it can build calcium carbonate Tropical waters are low in P and N and would be like deserts (generally, beautifully clear) Instead, reefs capture nutrients and grow

Loss of Coral due to: 1.Increased CO 2 decreases CaCO 3 formation 2.Overfishing increases alage growth that competes with corals for nutrients 3.Ag runoff also increases algae growth 4.Deforestation increases silt in water 5.Blast fishing 6.Increased temperature – coral polyps symbiotic with zooxanthellae plant; as temp incr, the zoox produce oxygen radicals and polyps expell the zoox; coral becomes white (coral bleaching)

Effects of Increased CO 2 - Trees Distribution of tree species in Peru highlands On average, trees migrate upward by 8 feet per year as temperatures increase Some trees migrate upward by 100 feet per year (Schefflera) Thus, important to have continuous ecosystems through the elevations (not fragments)

18 Global Warming – how much? Change in overall temperature, expect to see C increase by 2030 AND C increase by 2100 Changes magnified at poles – due to reduced reflection of sun by ice