1. Physics of Planetary Climate Cors221: Physics in Everyday Life Fall 2010 Module 3 Lecture 8: Climate During This Interglacial

2. From Last Time Earth emits more energy in infrared blackbody radiation from the poles than the poles receive from the Sun. Global atmospheric circulation moves heat from the equator to the pole. Ocean currents, including the Gulf Stream and the thermohaline circulation (THC) move even more energy to the pole from the equator. El Nino – Southern Oscillation (ENSO) is a change in temperatures of the east Pacific caused by changing winds emanating from between Indonesia and Australia. Repeats on 3-8 year timescales but not regularly; causes shifts in climate that vary across the globe. Clouds on the day side of the Earth cool the planet. Clouds on the night side of the Earth warm the planet. Very large volcanic eruptions can send volcanic ash into the stratosphere that cools the planet for a few years until the ash rains out.

3. Holocene Temperatures

4. Holocene Temperatures 2

5. Temps Last 2000 Years

6. Temps Last 130 Years

7. Temps Last 30 Years

8. Solar Flux Measurements

9. Solar Flux Inferred from Sunspots

10. Central European Temperatures

11. CO 2 Levels Measured Mauna Loa

12. CO 2 Levels For 1000 Years

13. CH 4 Levels for 1000 Years

14. N 2 O Levels for 1000 Years

15. Sulfate Levels for 1000 Years

16. Change in Earth’s Outgoing Infrared Blackbody Radiation

17. Natural Forcing Model

18. Human Influence Forcing Model

19. Natural+Human Forcing Model

20. Cause of Warming from Models

21. Tracing the Logic Train CO 2 Global Warming Infrared Absorption Greenhouse Effect

22. Key Points Glaciers melted off rapidly at the start of this interglacial ~15000 years ago. Brief reversion during Younger Dryas perhaps due to stopping of the thermohaline ocean circulation. General slow decline since onset of present interglacial. Instrumental temperature record shows warming since 1900 or so. Satellite temperatures show warming trend since late 1970s. Planetary temps have been pretty flat last 10 years – statistical outlier? Carbon Dioxide and other greenhouse gases have sharply increased in concentration over the past 150 years. Satellites have directly measured a decrease in Earth’s emitted infrared blackbody spectrum resulting from increased absorption due to carbon dioxide, methane, and other greenhouse gases. Patterns of planetary temperature are consistent with a greenhouse origin to the warming.