1. Acid Rain Revisited Hubbard Brook Research Foundation Science Links Bridging the Gap between Science and Policy

4. Outline Patterns of Emissions and Deposition Forest Ecosystem Effects Ecosystem Response to Management Strategies Conclusions

5. Patterns of Emissions and Deposition

6. Time (years)

7. allowances allocated for that year all sources Phase I sources Phase II sources SO2 Emission Reductions under the Acid Rain Program

8. Source: Cantor Fitzgerald

9. SO 2 Emissions and the Allowance Bank, 1995- 2003 8.7 11.713.5 15.0 16.6 21.6 18.8 18.1 19.9 Allowances allocated that year Unused allowances from previous year (bank) Actual emissions from affected sources SO 2 Emissions (million tons)

10. 1990 emissions Phase I (1995-1999) average emissions Phase II (2000-2003) average emissions scale: 1990 emissions in Ohio were 2.2 million tons SO 2 Emission Reductions, by State

14. projected emissions level in the absence of Title IV 8.1

15. 1990 emissions Phase I (1996-1999) average emissions Phase II (2000-2003) average emissions scale: 1990 emissions in Ohio were 500,000 tons NO x Emission Reductions, by State

18. Source Area Includes: VT, MA, NY, NH, CT, RI, ME, OH, PA, DC, MD, NJ, DE, MI, VA, WV, QUE, ONT

21. Forest Ecosystem Effects

23. Soil Acid Rain Effects Soil S and N enrichment Nutrient cation (Ca 2+, Mg 2+) depletion Al mobilization

26. Aquatic Effects

31. Summary (n=1469) No. of Lakes(%)Surface area (ha)(%) pH < 5.0352242,0008.4 ANC < 0 µeq/L388262,65011

32. Ecosystem Response to Management Strategies

33. Critical Chemical Indicators for Ecosystem Response to Acidic Deposition Terrestrial Soil and soil water Ca/Al < 1 Soil base saturation < 20% Aquatic Surface waters pH 2  mol/L

37. Ali (µmol/L) pH ANC (µeq/L) NO 3 (µeq/L) SO 4 (µeq/L)

45. Model Predictions of the Response of Soil and Water to Acidic Deposition: Past and Future

46. Climatic data Solar radiation Precipitation Temperature PnET Water balance Photosynthesis Living biomass Litterfall Net Mineralization BGC – Surface water Aqueous reactions Uptake Deep water flow Shallow water flow Weathering Wet Deposition Dry Deposition BGC Aqueous reactions Surface reactions Cation exchange Adsorption Humic binding Aluminum dissolution/precipitation

48. Policy or Proposal NO x (million short tons) SO 2 (million short tons) Deadline for Implementation 4 Pollutant? 1990 Clean Air Act4.68.92010No Jeffords Bill S.556 (as amended) 1.5 66% reduction from 1997 levels 2.25 75% reduction from Phase II levels of 1990 CAAAs 2008Yes Smith Bill S.2815 (Clear Skies) 2.1 by 2010 1.7 by 2018 67% of current levels 4.5 by 2010 3.0 by 2018 73% of current emissions 2010 and 20183 pollutant Carper Bill S.843 (Clean Air Planning Act of 2003) 1.87 by 2009-2012 1.7 after 2013 4.5 by 2009-2012 3.5 by 2013-2015 2.25 after 2016 2009, 2013, 20163 pollutant Clinton Bill S.588Approx. 2.1 in 2004-2006 56% reduction from 1990 levels Approx. 1.38 70% reduction from 1990 CAAAs levels Approx. 4.45 by 2007 50% reduction from 1990 CAAAs levels 2004-2006: 2007 No

51. SO 2 Cap and Trade Program: Expected Annual Costs by 2010