MET 112 Global Climate Change Ozone Hole and Human Connection Professor Menglin Jin San Jose State University Department of Meteorology Research Projects Examples 1 http www youtube com watch v GSws08S9mQE Example 2 Why are automakers suing California 1 For regulating emissions of CFCs 2 For limiting number of SUV sales emissions of nitrogen 3 For limiting number of minivan sales 4 For regulating GHG emissions http www nytimes com 2006 09 21 business 21auto html Why is California suing automakers 1 For suing California in the first place 2 For violating emission standards 3 For producing autos that contribute to global warming 4 For producing ozone depleting gases Suggest to read The Ozone Hole http www theozonehole com Basic chemistry of ozone depletion http www nas nasa gov About Education Ozone chemistry html Lowest value of ozone measured by TOMS each year in the ozone hole Ozone Hole Ozone depletion describes two distinct but related observations a a slow steady decline of about 4 percent per decade in the total amount of ozone in Earth s stratosphere since the late 1970s and b a much larger but seasonal decrease in stratospheric ozone over Earth s polar regions during the same period The latter phenomenon is commonly referred to as the ozone hole In addition to this well known stratospheric ozone depletion there are also tropospheric ozone depletion events which occur near the surface in polar regions during spring http en wikipedia org wiki Ozone depletion Vertical Layers of the Lower Atmosphere Ozone Ozone is found in boundary layer as well as in stratosphere layer The former is one of greenhouse gases video http www met sjsu edu metr112videos MET 20112 20Video 20LibraryMP4 ozone 20hole 20and 20human 20connection Ozone sequence since 1979 Notice the seasonality of O3 in stratosphere Ozone Formation through Splitting of Oxygen by Ultraviolet Radiation Absorption of Ultraviolet Radiation by Ozone This figure was prepared by Robert A Rohde ultraviolet light UV light harmful UVB wavelengths 270 315 nm Ozone Hole Reductions of up to 70 in the ozone column observed in the austral southern hemispheric spring over Antarctica and first reported in 1985 Farman et al 1985 Formation and destruction of ozone Sunlight is the major energy source for both making and destroying stratospheric ozone When an Oxygen molecule absorbs a photon of light with a wavelength shorter than 200 nanometers 1 billionth of a meter the energy splits the molecule into two Oxygen atoms One of these atoms can react with another Oxygen molecule to form an Ozone molecule Up to 98 of the sun s high energy ultraviolet light UV B and UV C are absorbed by the destruction and formation of atmospheric ozone The global exchange between ozone and oxygen is on the order of 300 million tons per day http www nas nasa gov About Education Ozone chemistry html Dobson Units Total Ozone Content from Nimbus 7 TOMS March 1990 500 465 430 395 360 180 120 W 60 W Halley Bay 60 0 E 120 E 180 290 255 220 185 150 115 Total Ozone Content from Nimbus 7 TOMS June 1990 180 120 60 0 60 120 180 Total Ozone Content from Nimbus 7 TOMS September 1990 Decembe r 1990 90 N Dobson Units Total Ozone Content from Nimbus 7 TOMS 500 465 60 N 430 395 30 N 360 325 0 290 255 30 S 220 60 S 185 150 90 S 115 Total Nimbus 7 TOMS Ozone Content from 0 W Septem ber 90 1990 60 30 S S E Novem ber 90 1990 180 60 30 S S October 90 1990 60 30S S 90 W 60 30S S August 1990 0 180 E 500 465 430 395 360 290 255 220 185 150 115 Total Ozone Content from Nimbus 7 TOMS 0 90 E 60 30 S S 90 W 0 60 30S S October 1979 Octob er 1985 90 180 60 30 S S Octob er 90 1988 60 30S S W Octob er 1982 180 E Global Ozone Human activity Climate and Weather Climate Change Science Understanding Policy Maker successful example is Response to Ozone Hole Where are the highest concentrations of ozone located 1 2 3 4 In large cities The stratosphere The troposphere Near volcanoes Ozone Depletion Topics History of Ozone Depletion The Ozone Hole what where why Ozone into the future Early concerns of ozone depletion History of Ozone Depletion connection between human and nature Chlorofluorocarbons CFCs developed in 1940 s and 50 s as Refrigerants propellants fire retardants 1970 s CFCs detected in upper atmosphere Many of these have long atmospheric lifetimes 10 s to 100 s of years 1974 Rowland and Molina propose that CFC s can destroy ozone in the stratosphere CFC contain chlorine Cl Chlorine can destroy ozone rapidly Video http www met sjsu edu metr112 videos video http www met sjsu edu metr112videos MET 20112 20Video 20LibraryMP4 ozone 20hole 20and 20human 20connection Ozone 1 mp4 Ozone Hole Recipe Ingredients Science interpretation Chlorine gas Cold Temperatures 80C Chlorine gas is abundant in atmosphere due to CFC s Cold Temperatures 80C only occur over Antarctica during the cold winter Instructions Allow cold temperatures to form Polar Stratospheric Clouds 1 2 weeks Polar Stratospheric Clouds allow ozone friendly chlorine to be transformed into ozone destroying Allow time for polar stratospheric chlorine clouds to convert chlorine gas into ozone destroying chemicals 1 month Ozone depletion then starts when sun returns to Antarctica in the spring Bake ingredients with sunlight What is being done about ozone depletion Montreal Protocol 1988 international agreement to reduce ozone depleting chemicals Further amendments accelerated the phase out Developed countries have switched to HCFC s more ozone friendly Developing countries have until 2004 5 to phase out CFC s Montreal Protocol The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion The treaty was opened for signature on September 16 1987 and entered into force on January 1 1989 followed by a first meeting in Helsinki May 1989 Is the Montreal Protocol working Seems to be Recent observations indicate that chlorine is beginning to decline in the atmosphere Kyoto protocol uses similar approach Start off with small achievable steps Further amendments accelerate reductions What are predictions for the future Model simulations suggest atmospheric chlorine will return to pre 80 s level In next 50 years or so A slow ozone recovery should follow decreasing chlorine concentrations Uncertainties still remain Phase out of CFC s Influence of global warming Model Prediction for the