Acid Rain What goes up, must come down To download: Shift Left Click PowerPoint 97 Please respect copyright on this material Key Points Enhanced acidity (average pH < 5.0) – rain naturally weakly acidic from dissolved CO2 A product of industrial air pollution Problems in regions downwind Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading Acidity of Rainfall (pH) 1996 National Acid Deposition Program Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution – – SO2 from coal, oil NOx from automobiles, electric generation Problems in regions downwind Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading Principal Sources Electric Generators Refineries How Acid Rain Is Formed U.S. Environmental Protection Agency Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution Problems in regions downwind – – – Kills fish in lakes Destroys paint, stonework Contributes to forest dieback / decline • Buffered temporarily by basic soils Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading Tolerance of Fish to Acidity Effects of Acid Rain on Lakes Range from no effect to completely barren Variable from lake to lake Basic rocks (e.g. limestone) neutralize acidity in groundwater http://www.geocities.com/RainForest/Vines/7948 Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution Problems in regions downwind – – – Kills fish in lakes Destroys paint, stonework Contributes to forest dieback / decline • Buffered temporarily by basic soils Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading Acid Rain on Structures Accelerates decay of stonework Ruins finishes on cars and other paint work King’s College, Cambridge, England : The Chapel Decay of Stonework German sandstone statue from 1702 photographed in 1908 (left) and 1969 (right). Photo: Westfäliches Amt für Denkmalpflege. Courtesy Norwegian Department of Environment Effects on Marble Column capital volute, Jefferson Memorial, Washington, D.C. Marble surfaces exposed to rain develop a rough "sugary" texture because the calcite grains are loosened as the edges dissolve in the rain water. Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution Problems in regions downwind – – – Kills fish in lakes Destroys paint, stonework Contributes to forest dieback / decline • Buffered temporarily by basic soils Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading Forest dieback Many causes of dieback – shade – insects – climate Acid rain contributes – – leaf damage nutrients leached from soil Alan Rebertus- University of Missouri Effects of Acid Rain? German forest Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution Problems in regions downwind Sulfate aerosol conceals greenhouse warming – cools Northern Hemisphere continents by day – global effect much less than CO2 induced warming – controlling acid rain increases global warming Reduction facilitated by SO2 emissions trading Sulfate Aerosol & Global Warming SO2 ->Sulfate aerosol -> Acid Rain Sulfate aerosol reflects sunlight -> cools the Earth -> part offsets CO2 Cooling over N.H. continents by day Estimated contributions to global warming Intergovernmental Panel on Climate Change Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution Problems in regions downwind Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading – Established in U.S. by Clean Air Act 1990 – Enables stricter standards than command and control approach – Presumes effective monitoring of actual emissions – Prototype for international allowance trading of CO2 Causes of Acid Rain U.S. Environmental Protection Agency Regulation of Emissions large point sources Command – – – the traditional approach mandate cleanup technology accept best efforts Market – – – – and control incentives novel approach Clean Air Act 1990 allowance required for actual emissions open market for trading allowances mandate total allowances issued Trading Emissions Allowances Requires credible monitoring of actual emissions Market value of allowances – – provides incentive to invest in more efficient technology allows individual scheduling of plant replacement Price rises till weak demand controls total emissions Less political intrusion in management Application to SO2 Assumes unit emissions in different places are equivalent ( a rough approximation) Electric utilities only – – – most of the problem (for SO2) well organized institutions forward planning usual Allowances may be banked for future use, but not used ahead of time Congress set total emissions through 2025 – the screws tighten in 2000 $ Price of 1 ton SO2 Emissions U.S. Environmental Protection Agency Emission Allowances Trading: a Good Idea? A right to pollute? – We all pollute the environment Can emissions be credibly monitored? – Essential to link responsibilities to rights Is there an efficient market? – Low transaction costs, no monopolies Do similar emissions have equivalent effect? So far, so good ... – A prototype for international CO2 controls • Joint Implementation Key Points Enhanced acidity (average pH < 5.0) A product of industrial air pollution – – SO2 from coal, oil NOx from automobiles, electric generation Problems in regions downwind – – – Kills fish in lakes Destroys paint, stonework Contributes to forest dieback / decline • Buffered temporarily by basic soils Sulfate aerosol conceals greenhouse warming Reduction facilitated by SO2 emissions trading Sources of Information U.S. Environmental Protection Agency