Climate Change Law and Policy

1. Climate Change Law and Policy

2. Overview of the carbon cycle and climate change

3. Short and geological carbon cycles

5. Greenhouse gas emissions, sources and concentrations

6. Relevant Terms • Greenhouse gases (GHGs) = • gases that absorb infrared radiation [without GHGs, the radiation would escape to the atmosphere]

7. Relevant Terms • Global Warming Potential (GWP) = • tool to equate the relative warming impacts and atmospheric lifetimes of different GHGs, with CO2 = 1

8. Relevant Terms • Carbon Dioxide Equivalent (CO2eq) = • tool used to compare a gas’s radiative forcing to CO2

9. GWPs and different gases Why do we care about different GWPs? Should governments regulate GHGs with different GWPs through a single treaty or should they use different treaties?

11. GWPs and different gases • GWPs regulated through international climate treaties • CO2 (carbon dioxide) – GWP = 1 • CH4 (methane) – GWP = 21 • N2O (nitrous oxide) – GWP = 310 • HFCs (hydrofluorocarbons) – GWP = 1,000 to 12,000 • PFCs (perfluorocarbons) – GWP = 5,700 • SF6 (sulfur hexafluoride) – GWP = 23,900

12. Evidence of Climate Change

13. The Mauna Loa Curve

14. IPCC chart showing increases in GHGs over past 2,000 years

15. The Relationship Between Increased GHGs and Global Temperatures

16. Average surface temperature over past 20,000 years

17. Trend in global average surface temperatures

18. Global v. Regional Temperatures • Global temps = consistent temperature rise • Every one of the last 12 years = hottest on record • Has been that way since about 1995 • Regional temperatures will vary • Northern latitudes – expected to see even greater warming than average • Poles are seeing greater temperature increases than equator • but “warming” on a global level will be the norm

19. Causes of Climate Change

20. Increased Emissions and Declining “Sinks” • 3 major issues at play • Increasing emissions • Depleting “reservoirs” • Reservoirs = places that store GHGs that were already removed • Declining “sinks” • Sinks = features that remove GHGs from atmosphere

21. Declining “Sinks” • Why declining? • Forest clearing = removing areas that could be taking up carbon dioxide • If converted to non-forested or urban use • Various changes in climate may diminish ability for natural areas to remove carbon dioxide • Oceans absorbing less carbon dioxide

22. Sources

23. GHGs emitted – by pollutant (some sector)

27. CO2 Emissions • Sources: • Fossil fuel combustion • Energy • Industry • Transportation • Cement production • Deforestation

34. Methane Emissions • Sources • Agriculture • Livestock = 37% of global methane emissions • Landfills and waste decomposition • Coal mines and oil and gas production

35. Methane: Australia

36. Methane: Nigeria

37. Methane: Italy

38. Methane: Vietnam

39. Methane: United States

40. Methane: China

41. Increased nitrous oxide concentrations • Agriculture • Livestock/manure • Soils (nitrogen fertilizers) • Car exhaust • Industrial processes

42. Increased F gas concentrations • Human-made chemicals • Designed as replacements for ozone-depleting chemicals • Used in manufacturing/air conditioning/electronics industries • Relatively small amounts emitted, but huge GWPs

43. Feedback Loops • “positive” loops = increase the process underway • GHG emissions → warmer surface temps → melting permafrost → increased emissions → increased temps • GHG emissions → warmer temps → melting ice → less reflection → increased temps • Negative loops = minimize impacts • GHG emissions + warmer temps → more plant growth → less carbon dioxide in atmosphere

44. Effects of climate change

45. Melting Ice

46. Melting ice • Melting ice in Arctic/Greenland/Antarctica • Massive ice sheets on land ending up in water = sea level rise • Melting ice everywhere • Less freshwater for drinking/agriculture/etc. • Flooding and then droughts • Habitat loss • Polar bears • Coldwater fish

47. How ice masses on land become ice masses in the sea

48. Meltwater in Greenland

49. Larsen B ice sheet collapse in Antarctica