MET 112 Global Climate Change - Lecture 12 Climate Change: Connections Eugene Cordero San Jose State University Outline § Ozone Depletion § Water - Film § Perspectives 1
Why is the ozone layer important § Ozone acts as the Earth’s protective shield against the Sun’s harmful Ultraviolet radiation (UV radiation). § The natural development of the ozone layer permitted life to evolve above water. § Without the ozone layer, life would not exist on Earth! MET 112 Global Climate Change 3
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Ozone, the good and the bad Ozone is often confused: Stratosphere Altitude (km) Good ozone: Stratospheric ozone The ozone layer Bad ozone: Tropospheric ozone Smog Troposphere Note: ozone is also greenhouse gas ozone amount MET 112 Global Climate Change 7
At what time of year would you expect UV values to be the highest? 1. 2. 3. 4. Winter Spring Summer Fall MET 112 Global Climate Change 8
Cities with high levels of air pollution correspond to high levels of 1. Stratospheric ozone 2. Mesospheric ozone 3. Tropospheric ozone MET 112 Global Climate Change 9
Where are the highest concentrations of ozone located? 1. 2. 3. 4. In large cities The stratosphere The troposphere Near volcanoes 0 of 250 MET 112 Global Climate Change 10
Ozone Depletion Topics § History of Ozone Depletion § The Ozone Hole: what, where, why? § Ozone into the future MET 112 Global Climate Change 11
Early concerns of ozone depletion MET 112 Global Climate Change 12
History of Ozone Depletion § 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 Molina propose that CFC’s can destroy ozone in the stratosphere. – CFC contain chlorine (Cl) – Chlorine can destroy ozone rapidly MET 112 Global Climate Change 14
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Ozone Hole Recipe Ingredients: Science interpretation § Chlorine gas § Cold Temperatures (~-80 C) § Chlorine gas is abundant in atmosphere due to CFC’s § Cold Temperatures (~-80 C) 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 § Allow time for polar stratospheric clouds ozone destroying chlorine. 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. § Ozone hole grows from late August § Presto, a delicious ozone hole! through till October. MET 112 Global Climate Change 16
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. MET 112 Global Climate Change 18
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 MET 112 Global Climate Change 19
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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 § __________ MET 112 Global Climate Change 22
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What is the connection between ozone depletion and global warming? § No direct connection between these environmental issues. § However: Global warming may enhance ozone depletion § Global warming produces: – Tropospheric warming & – Stratospheric cooling MET 112 Global Climate Change 25
What is the connection between ozone depletion and global warming? § An increase in greenhouse gases traps more heat and thus – The stratosphere tends to cool (stratospheric cooling) § Therefore, if the stratosphere cools, then § Ozone hole chemistry – PSCs will likely increase – So slightly more ozone depletion § Global warming will delay recovery of ozone layer MET 112 Global Climate Change 27
Over the last 100 years, global tropospheric ozone levels have been 1. increasing 2. decreasing 3. nearly constant 0 of 250 MET 112 Global Climate Change 28
The chemical that triggers rapid ozone loss associated with CFCs is 1. 2. 3. 4. Carbon Dioxide Nitrogen dioxide Methane Chlorine 0 of 250 MET 112 Global Climate Change : 20 29
The Antarctic ozone hole develops during 1. 2. 3. 4. SH Spring SH Summer NH Spring NH Summer 0 of 250 MET 112 Global Climate Change 30
Global ozone values are expected to recover in the next 1. 2. 3. 4. 10 years 30 years 50 years 100 years 0 of 250 MET 112 Global Climate Change : 30 31
Drinkable Water (Freshwater) § Of all the water in the world, 97% is sea water (salt) § Freshwater occupies only 3% of the Earth’s water § Of the freshwater, 77% of freshwater is locked up as ice. § Water is the most important natural resources in the world. MET 112 Global Climate Change 33
Drinkable Water (Freshwater) §Today, over 1 billion people don’t have access to safe drinking water §The predictions of climate change suggest that access to fresh water will be made more difficult – Changes in location and quanitity of precipitation – Raising sea levels MET 112 Global Climate Change 34
Economic interest Water "One of the world's great business opportunities. It promises to be to the 21 st century what oil was to the 20 th. " - Fortune Magazine MET 112 Global Climate Change 35
While watching the documentary, Thirst, think about the how the predictions of future climate change (including water resources) will intersect with the interest and impact of water privatization.
Final Exam question: Write an essay relating how the predictions of future climate change may intersect with the issue of water privatization.
Local/National Policies What are local/national governments doing to reduce GHG emissions? 1. 2. 3. 4. 5. 6.
Metr 112: Main points Let’s come up with the three most important points (i. e concepts or themes) covered in this course. 1. 2. 3. MET 112 Global Climate Change 41
Summary Over the last 100 years and especially over the last thirtyfive years, the Earth climate has experienced a significant warming trend. Current levels of greenhouse gases are higher than anytime over the last 400, 000 years and likely longer. Science is confident that humans are responsible for a majority of the warming observed over the last 50 years. The Earth’s climate will continue to warm and this warming will place significant stress on social systems throughout the world. Significant climate change mitigation is urgently needed to reduce negative impacts. Climate Change MET 112 Global 42
Your opinion… MET 112 Global Climate Change 43
Global warming is under way? 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 44
The US should sign the Kyoto Protocol 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree MET 112 Global Climate Change 46
Government should act to reduce greenhouse gas emissions even if it means raising energy prices 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 47
If you were going to help mitigate global warming, which change would you feel most comfortable making. 1. Taking public transport more 2. Paying more for gasoline 3. Altering your food choices 0 of 250 MET 112 Global Climate Change 48
Global warming will affect your life? 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 49
I would vote for a law that raises gasoline taxes by $0. 05 per gallon to improve energy efficiency 1. Yes 2. No 0 of 250 MET 112 Global Climate Change 50
I would vote for a law that raises gasoline taxes by $0. 25 per gallon to improve energy efficiency 1. Yes 2. No 0 of 250 MET 112 Global Climate Change 51
I would vote for a law that raises gasoline taxes by $1. 00 per gallon to improve energy efficiency 1. Yes 2. No 0 of 250 MET 112 Global Climate Change 52
To help mitigate the impacts of climate change, I’m willing to reduce the number of miles I drive and fly 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 53
To help mitigate the impacts of climate change, I’m willing to change my diet 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 54
To help mitigate the impacts of climate change, I will encourage my friends and family to reduce energy use 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 55
To help mitigate the impacts of climate change, I feel compelled to do whatever I can to reduce greenhouse gas emissions 1. 2. 3. 4. 5. Strongly Agree Neutral Disagree Strongly Disagree 0 of 250 MET 112 Global Climate Change 56
Local Action: Does It Make a Difference? “Never doubt that a small group of thoughtful, committed citizens can change the world; indeed it’s the only thing that ever has. -- Margaret Mead. MET 112 Global Climate Change 57
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