1. Human Influences on Climate Greenhouse effect Feedbacks Northward movement of the jet streams Changing Land Surfaces Heat Islands Consequences of Greenhouse Effect

2. Simple Greenhouse Model

3. Greenhouse Effect

6. Ice-albedo feedback effect

7. Positive Feedback

8. Negative Feedback

9. CLIMATE FEEDBACK MECHANISMS ·POSITIVE AND NEGATIVE FEEDBACKS ·WATER VAPOR - POSITIVE ·ICE COVER - POSITIVE.CLOUDS - POSITIVE AND NEGATIVE - MAINLY NEGATIVE

10. Fig. 7-27, p. 191 Positions of the jet streams

11. Jet Streams on March 11, 1990 Sub-tropical = Blue, Polar = Red

12. Fig. 8-30, p. 231 Relation between jet stream and high and low pressure systems

13. % DAYS WHEN JETSREAM WITHIN 150 MILES OF BALTIMORE

14. Frontal Movement and Climate Change Increasing evidence that the Polar and Sub- tropical jet streams in the Northern Hemisphere are moving northward. This implies that the weather patterns associated with the jets (fronts) are also moving northward As the sub-tropical jet moves northward so do the high pressure systems associated with this jet. Expect drier summers Could increase in greenhouse forcing in the tropics lead to a stronger Hadley cell circulation, and hence to a movement of the jet?

15. Fig. 15.8 Disappearance of the Aral Sea, during the period from 1973 to 2000. Largely due to diversion of water from the rivers feeding the sea for irrigation.

16. Aral Sea Government of the Soviet Union diverted waters feeding this inland lake to provide water for the growing of cotton. Aral Sea began shrinking rapidly Climate has also changed in the region Asian ‘Dust Bowl’ Increased salinity destroyed fishing industry

17. Fig. 15.9 Roadways and buildings reduce evapor-transpiration and absorb more solar radiation than the surrounding rural regions.

18. Washington DC Heat Island

20. THE CLIMATE OF CITIES URBAN HEAT ISLAND TEMPERATURES ARE GENERALLY HIGHER THAN IN RURAL AREAS, CREATING AN 'ISLAND' OF WARMER AIR. CITIES ARE GENERALLY CLOUDIER, FOGGIER, WARMER, WETTER WHY? ROCK-LIKE MATERIALS OF CITY HAVE HIGH THERMAL CAPACITY IMPERVIOUS SURFACES REMOVE PRECIPITATION QUICKLY LARGE SOURCES OF HEAT ATMOSPHERIC POLLUTION TRAPS RADIATION TALL BUILDINGS ALTER THE AIR FLOW INCREASED PRECIPITATION THERMALLY INDUCED UPWARD MOTIONS

21. Fig. 15-1, p. 442

24. CONSEQUENCES OF GREENHOUSE WARMING.WATER RESOURCES AND AGRICULTURE - CHANGES IN PRECIPITATION PATTERNS - LENGTH OF GROWING SEASON.SEA LEVEL RISE -.MELTING OF GLACIERS PLUS THE THERMAL EXPANSION OF THE OCEANS - HAS RISEN 10-25 CM OVER PAST CENTURY.NEW WEATHER PATTERNS - HIGHER FREQUENCY AND GREATER INTENSITY OF HURRICANES BECAUSE OF WARMER SEA SURFACE TEMPERATURES. SHIFTS IN PATHS OF CYCLONIC STORMS - PRECIPITATION PATTERNS..SHIFTS OF OCCURRENCES OF TORNADOES..MORE INTENSE HEAT WAVES AND DROUGHTS IN SOME REGIONS AND LESS IN OTHERS.