Chapter 3: Climate Change and the Energy Transition

1. Chapter 3: Climate Change and the Energy Transition

2. “Ever since civilization began, each generation has left the next a planet similar to the one it inherited. Our generation may be the first to abandon that tradition.”

3. Evidence of Climate Change • Earth’s average temperature has risen 0.6°C since 1970 • Projected to rise by up to 6°C by the end of the century • Sea level rose 7 inches in the 20th century • Projected to rise 3 to 6 feet by the the end of the century

4. Causes of Warming • Greenhouse gases: • CO2 = 63% • Methane = 18% • Nitrous oxide = 6% • Other gases = 13% • Atmospheric Brown Clouds

5. Sources of Carbon • Electricity generation, heating, transportation and industry • Only about 5 million tons are absorbed by oceans, soil and vegatation, the rest remains in atmosphere • In 2008: • 7.9 billion tons emitted by burning of fossil fuels • 1.5 billion tons emitted by deforestation • Total of 9.4 billion tons

6. Sources of Methane • Mostly human caused through agriculture • Landfills • Thawing of permafrost • Arctic soil contains more carbon than currently resides in the atmosphere • Problem: permafrost is melting

7. Sources of Atmospheric Brown Clouds • Soot particles from burning coal, diesel fuel and wood • Affect climate in 3 ways: • Intercept sunlight, heating upper atmosphere • Reflect sunlight, lowering earth’s surface temperature • When deposited, darken surfaces and accelerate melting  Particular concern over Tibetan Plateau, Himilayas, Sierra Nevadas

8. Effects of Climate Change • Diminish crop yields  lower food production • Melt mountain glaciers  feeding rivers • Generate more destructive storms • Increase severity of floods • Intensify drought • Cause more frequent/destructive wildfires • Alter ecosystems worldwide  loss of species

9. Melting ice, Rising seas • Rapid shrinking of the Earth’s 2 largest ice sheets • Greenland, potential to raise sea level by 23 ft • West Anarctica, potential to raise by 16 ft

10. The Arctic Region • Arctic is warming 2x faster than the rest of the planet • In surrounding regions (Alaska, western Canada, eastern Russia) winter temperatures have risen 3-4°C over last half century • 1979-2006, summer sea ice shrinkage accelerated to 9.1%/decade • 2007 (record melt year), sea ice shrank to an area some 20% smaller than the previous melt record in 2005 • Multiyear sea ice is not recovering in winter

11. Albedo Effect • Self – reinforcing trend, accelerating melt • Typically, when sunlight strikes sea ice, 30% is absorbed and 70% is reflected back • As ice melts, sunlight hits darker surface of water and 94% is absorbed and only 6% is reflected back

12. Greenland • April 2004-April 2006, lost ice 2.5x faster than in preceding two years • Ice melt seeps through cracks in glacier, lubricating surface between glacier and rock accelerating glacial flow and calving • Huge masses of ice falling into sea are causing minor earthquakes

13. NASA Satellite Data • 2007 – ice shelves shrank by 24 square miles • 2008 – ice shelves shrank by 71 square miles