EPA Site Covers almost entire climate change topic! Global Issues Global Warming Ozone Depletion EPA Site Covers almost entire climate change topic!

The Atmosphere Four distinct zones Troposphere: 75% of total mass Temperature Relative gas concentrations Pressure Troposphere: 75% of total mass 5 to 10 miles What happens to temperature? Stratosphere: to about 31 miles Low water vapor; ozone 1000x higher than troposphere What is source and importance of ozone? Ionosphere

Solar Radiation How much reaches the earth’s surface? Selective absorption in the atmosphere Visible light Ultraviolet Infrared Albedo Snow vs. a dark surface Average earth’s is 5% (due to oceans)

Earth’s Radiation All energy absorbed by surface is reradiated But… how is this different than incoming? Reradiated as infrared vs. incoming visible light So What? What gasses absorb infrared?

Climate and Climatic Catastrophes Climate vs. weather Gradual climatic change: adaptation, evolution Abrupt climatic change: mass extinctions 65 million years ago (end of Cretaceous) Up to dozen such great climatic changes What is the evidence of past climatic changes? Developing models for future changes

Some Numbers - Global temperature increase, 1750-1990: 1.25° F or about 0.8 degrees C, most in the last 40 years Rate of temperature increase since 1990: 0.72° F or 0.5 degrees C. IPCC's estimate of global temperature increase by 2100: 2.5° F - 10.4° F (1.4-5.8 deg C) Temperature increase in the Arctic since 1970: 4° F Data source: IPCC report (over 2000 leading climatologists)– and, US National Academy of Sciences Videos with some data NOAA data and graphs

Some Numbers - Carbon Twice pre-industrial concentrations by 2100 Quantity of CO2 in the atmosphere before the industrial revolution: 288 parts per million Quantity of CO2 in the atmosphere in 2000: 370 parts per million Years since Earth's CO2 level was last this high: 20 million Annual increase of 0.5% % of the enhanced greenhouse effect caused by CO2 52.5% % of the enhanced greenhouse effect caused by methane: 17.3% % of the enhanced greenhouse effect caused by ozone: 12.5%

A Carbon Video Take a look at a creative look at at carbon atom – enjoy

Evidence of Climate Change Ice cores Tree rings Historical records Slideshow Short Videos – (use these_ Discovery Channel A Picture Gallery Some Graphs Copenhagen and REDD

Other Greenhouse Gasses Methane - s Absorbs 20x to 30x as much heat as CO2 At this point not as large piece of the pie Sources: Ruminant animals, coal mines, pipeline leaks, landfills As earth warms: released from tundra (example of positive feedback system) Chlorofluorocarbons (CFCs) Nitrous oxides and ozone – air pollution from burning fossil fuels

Effects of Climatic Change Temperatures Middle and high latitudes much indrease Precipitation High latitudes wetter Mid latitudes drier Rising sea levels (appear to be increasing 2mm/year) Continental glaciers may melt - coastlines inundated Videos with several changes on our earth

Source is NOAA

Can CO2 Emissions be Reduced? Kyoto Protocol - 1997: industrialized nations Average 5.2% below 1990 by 2012 Has this been ratified? What was U.S. opposition How to enforce? No penalties IPCC Report: summary of the report

Can CO2 Emissions be Reduced? IPCC Report: summary of the report Cap and Trade –( trading emission allowances)

Some Scenerios Link to this graph at NOAA

Critical Thinking - What To Do? How certain should we be before acting? What are the potential economic consequences (of taking or not taking action)? Are there potential positives if we cut emissions even if the models are overly pessimistic? What will happen if we don’t act? Think of precautionary principle

Global Warming Quiz Take the Quiz

What Can You Do? Calculate your carbon savings at this EPA website Change starts with your stomach Reduce Your Carbon Footprint

El Nino La Nina- Trade winds move ocean surface currents westward Thermocline Upwelling of waters west of S.A. El Nino Indonesian Low Collapses; warm water moves east Jet stream drawn south- moist air drawn from Gulf and Pacific Are El Nino years becoming more frequent?

Ozone Depletion First detected “ozone hole” over Antarctica in 1985 1997: all ozone over Antarctica between 14 and 20 km destroyed Danger: more UV rays 1% decrease in ozone results in 2% increase in UV equals 1 million more skin cancers

Why is Ozone Being Depleted Antarctica - unique weather conditions CFC - Freon- a great refrigerant - Why? Propellants in aerosols - A What?? No longer propellants Helsinki Agreement (1989) - phasing out of all uses of CFC’s