3. Outline Earth from the perspective of Space Some basic science behind climate and global warming Effects of changing climate that we’re seeing now Effects to expect in the future Importance of embracing solutions now

8. Earth’s Air Nearly all of our air (99%) is made of oxygen (O 2 ) and nitrogen (N 2 ). Each of these molecules is made of two atoms: N N O O

9. Earth’s Air (<1%) Carbon dioxide (CO 2 ) and water vapor (H 2 O) are different! They have more atoms, so more ways to vibrate …So, they are very good at absorbing and emitting infrared (heat) radiation Molecules that have many ways to wiggle are called “Greenhouse” molecules

11. CO 2 is increasing…

12. Where Has CO 2 Come From?

13. But….How Much CO 2 Was There in the Past? We know from Studying ice cores

14. CO 2 over 400,000 years 370 ppm in 2000 Vostok (400k yr) Ice Core data (Petit et al, 1999) CO 2 388 ppm in 2008

15. CO 2 & Temperature

16. “Recent” Temperatures

27. The Impacts Surface temperatures increasing Glaciers, ice sheets, sea ice shrinking Dry areas drier; wet areas wetter Storms more intense Ocean temperature increasing Sea Level rising Ocean more acidic Ecosystems, agriculture affected

28. The Future… As world warms, changes (to ecosystems, coastlines, weather, agriculture) will continue Our Challenge: control & reduce the emission of CO2 No Magic Bullet

29. “Scientists are necessary, but not sufficient to solve the climate problem” Dr. Ralph Cicerone, President of the National Academy of Science, November 2007

30. Billions of Tons Carbon Emitted per Year Historical emissions 0 8 16 1950200020502100 Historical Emissions

31. 1.6 Interim Goal Billions of Tons Carbon Emitted per Year Current path Historical emissions Flat path Stabilization Triangle 0 8 16 1950200020502100 The “Stabilization Triangle”

32. 1.6 Billions of Tons Carbon Emitted per Year Current path Historical emissions Flat path 0 8 16 1950200020502100 Goal: In 50 years, same emissions as today “Stabilization Wedges” Wedges

33. Energy Efficiency & Conservation CO 2 Capture & Storage Stabilization Triangle Renewable Fuels & Electricity Store in Forests, Soils Fuel Switching Nuclear Energy 20072057 8 GtC/y 16 GtC/y Triangle Stabilization Possible Wedges (no magic bullet)

37. www.SallyRideScience.com

47. Projections of Surface Temp Land vs ocean! North vs South Global: 2º- 5ºC US: 3º - 6º C Arctic: 5º - 9º C B1 A1B A2

48. 2 2 = 4 billion tons go out Ocean Land Biosphere (net) Fossil Fuel Burning + 8 800 billion tons carbon 4 billion tons go in ATMOSPHERE billion tons added every year CO 2 “Budget” of the Atmosphere

49. 20th-Century Temperatures Black lines show observations, yellow lines show each model, red line shows model mean surface temps With all forcings, models capture much of historical record Bottom panels: model=blue, obs=black Without greenhouse forcing, models fail to match observations

50. Common Misconception “Predictions of future warming are based on extrapolation of recent warming trends” WRONG! They are based on the idea that when we add energy to the surface, it will warm up

51. Common Misconception “When we stop burning fossil fuel, the CO 2 will go away and things will go back to normal” WRONG! CO2 from fossil fuels will react with oceans, but only as fast as oceans “mix” About half of the fossil CO 2 will stay in the atmosphere for thousands of years after emissions stop!

52. Observations Much stronger trend on land than ocean North > South Surface > Troposphere Acceleration of trend

53. Imagine it’s 1800, and you’re in charge … Somebody presents you with a grand idea for transforming the world economy: Dig 8 billion tons of carbon out of the ground every year Build a system of pipelines, supertankers, railroads, highways, and trucks to deliver it to every street corner on the planet Build a billion cars every year, and a billion miles of roads to drive them on Generate and pipe enough electricity to every house to power lights & stereos & plasma TVs … “and here’s the itemized bill …”

54. The Wealth of Nations The US will build a power plant a week for the next 20 years. How much does that cost? China will increase CO2 emissions from electrical generation by 30% this year! How much does that cost? Imagine there were no taxes, except on CO2 … Everybody would be free to innovate and make money, but fuel would be very expensive What would happen?

55. Climate vs. Weather “Weather tells you what to wear today … climate tells you what clothes to buy!” Climate is an “envelope of possibilities” within which the weather bounces around Weather depends very sensitively on the evolution of the system from one moment to the next (“initial conditions”) Climate is determined by the properties of the Earth system itself (the “boundary conditions”)

56. Climate Predictability Predicting the response of the climate to a change in the radiative forcing is not analogous to weather prediction If the change in forcing is large and predictable, the response can also be predictable I can’t predict the weather in Fort Collins on April 18, 2008 (nobody can!) I can predict with 100% confidence that the average temperature in Fort Collins for June, 2008 will be warmer than the average for January!

57. Our Variable Star Changes of ~ 0.2% (= 2.7 W m-2) reflect 11-year sunspot cycle