Prof. Daniel Cohan Dept. of Civil & Environmental Engineering Rice University

Transcription

1 State of the Air: Air Quality and Climate Change in Texas and Beyond Prof. Daniel Cohan Dept. of Civil & Environmental Engineering Rice University

2 Outline State of the Air in Texas Ozone smog Particulate matter Climate Change Has Earth warmed? Why? Projections for future

3 Ozone: Good up high, Bad nearby 3

4 Stratospheric Polar Ozone Hole

5 Montreal Protocol drastically curtailed ozone depleting emissions WMO/UNEP Scientific Assessment of Ozone Depletion,

6 Stratospheric ozone has bottomed out, beginning to recover WMO/UNEP Scientific Assessment of Ozone Depletion,

7 Ground-level Ozone Smog CO 2, etc. HO 2 NO O 3 CO, VOC OH NO 2 VOC Hydrocarbons NO x Nitrogen Oxides O 3 7

8 Ground-level Ozone Impacts Health effects Strong oxidant, irritates lungs Linked to asthma and other respiratory illnesses Recently linked to mortality Damage to vegetation & crops Greenhouse gas Non-attainment of EPA standards 8

9 Ozone and Particulate Matter Non-Attainment US EPA sets ambient standards States must attain those standards Non-attainment drives priorities for policy, industry, and science Maps from US EPA 9 Source: U.S. EPA

10 Steps forming ozone in Houston Large releases of HRVOCs & NOx from Ship Channel Especially if upset conditions at a source Mix with NO x from city (mostly vehicles) Ozone forms in plume downwind 10

11 US air pollutant emissions declining, but CO 2 rose with energy consumption US EPA: Our Nation s Air: Status and Trends Through

12 Ozone Trends TCEQ 12

13 Particulate Matter Image from 13

14 Particulate Matter Particulate matter: airborne particles composed of a variety of chemical compounds Large particles settle out quickly Fine particles (<2.5 μm (PM 2.5 )) cause greatest damage to visibility (haze) and human health (respiratory, cardio-vascular, mortality) 14

15 Health effects Impacts of PM Fine particles go deep in lungs, to bloodstream Respiratory and cardiovascular disease Mortality Visibility/Haze Regulatory concern Houston barely attains current standard New, tighter standard under consideration 15

16 Fine Particulate Matter in Texas TCEQ 16

17 Key Climate Questions Has Earth warmed? (Measurement) Are humans responsible? (Attribution) Will warming continue? (Projections) Is that a problem? (Impacts) What should be done? (Policy) A policy/political question, though science can inform the search for solutions

18 Key Climate Questions Has Earth warmed? (Measurement) Are humans responsible? (Attribution) Will warming continue? (Projections) Is that a problem? (Impacts) What should be done? (Policy) A policy/political question, though science can inform the search for solutions

19 Observational evidence of climate change IPCC,

20 Long-term upward trend, modulated by volcanoes & El Nino NASA GISS: 20

21 Global US National Geographic 21

22 Additional evidence of warming IPCC, Physical Basis Technical Summary,

23 Physical & Biological Evidence of Warming Vast majority of observed changes in physical & biological systems are consistent with warming IPCC,

24 Fastest warming at northern high latitudes (Arctic) NASA GISS: 24

25 In the news: Arctic sea ice reaches all time minimum extent NASA Yellow line shows average minimum,

26 This summer s weather Anomaly ( C) relative to mean 26

27 Key Climate Questions Has Earth warmed? (Measurement) IPCC: Warming of the climate system is unequivocal Are we (via greenhouse gases) responsible? (Attribution) Will warming continue? (Projections) Is that a problem? (Impacts) What should be done? (Policy) A policy/political question, though science can inform the search for solutions

28 Rising Greenhouse Gas Levels Pre-industrial: ~280 ppm Pre-industrial: ~700 ppb

29 Earth s Energy Budget (Trenberth et al., BAMS, March 2009)

30 IPCC, 2007

31 Correlation of greenhouse gases and temperature in paleoclimatology CO 2,CH 4 and estimated global temperature (Antarctic ΔT/2 in ice core era) 0 = mean. Source: Hansen, Clim. Change, 68, 269, 2005.

32 IPCC, 2007 Both anthropogenic and natural forcings are needed to model temperature record

33 IPCC 2007 Conclusion on Attribution Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. IPCC, Summary for Policy Makers, 2007

34 Key Climate Questions Has Earth warmed? (Measurement) Are humans responsible? (Attribution) Will warming continue? (Projections) Is that a problem? (Impacts) What should be done? (Policy) A policy/political question, though science can inform the search for solutions

35 IPCC, 2007

36 Predicted Temperature Change for Middle Emission Scenario (A1B) 2020 s 2090 s IPCC, 2007

37 Known and Uncertain Known: Earth is already warming Greenhouse gases are increasing More greenhouse gases mean more energy returns to Earth s surface Uncertain: How will feedbacks magnify or dampen the effects of greenhouse gases? Clouds, ice, permafrost, etc. How will local climate patterns change? Rely on models of highly complex Earth systems

38 IPCC 2007 Conclusion on Predicted Warming For the next two decades a warming of about 0.2 C per decade is projected. Continued greenhouse gas emissions at or above current rates would cause further warming and induce many changes in the global climate system... IPCC, Summary for Policy Makers, 2007

39 Key Climate Questions Has Earth warmed? (Measurement) Are humans responsible? (Attribution) Will warming continue? (Projections) Is that a problem? (Impacts) What should be done? (Policy) A policy/political question, though science can inform the search for solutions

40 IPCC, 2007

41 Uncertainty in Precipitation Trends White areas: <66% of models agree on sign Stippled areas: >90% of model agree on sign 41 IPCC, 2007

42 Modeled impact of Year 2100 climate on Atlantic hurricanes: Fewer but stronger?? Bender et al., Science

43 Key Unknown: How Fast Will Sea Level Rise? So far, sea level rising only 0.3 meters/century IPCC, 2007

44 What if Sea Levels Rose 25 m? (Paleoclimate data may indicate that 3 C ~25 m sea level rise long-term) Images from James Hansen

45 Key Climate Questions Has Earth warmed? (Measurement) Are humans responsible? (Attribution) Will warming continue? (Projections) Is that a problem? (Impacts) What should be done? (Policy) A policy/political question, though science can inform the search for solutions

46 Need 7 policy wedges to stabilize CO 2 at 500 ppm Socolow and Pacala, Scientific 46 American, 2006

47 Example Wedges (Need 7 to stabilize at 500ppm) 47 Pacala and Socolow, Science, 2004

48 Costs of CO 2 mitigation options 48

49 No Regrets Approaches Efficiency may pay for itself in fuel savings Renewable energy reduces reliance on foreign imports Targeting non-co 2 warming (methane, black carbon soot particles) would improve air quality, health

50 Geoengineering Options 50

51 The Verdict Has Earth warmed? Yes Are humans responsible? Mostly Will warming continue? Yes, but how much and where? Is that a problem? Probably What should be done???? Policy/political question; science can help predict outcomes of various policy choices