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LEARNING FROM GLOBAL DISASTER LABORATORIES PART 11A: FUNDAMENTALS OF GLOBAL CLIMATE CHANGE

Explore the impacts of human activities on global warming, greenhouse gases, natural vs. unnatural greenhouse effects, and the role of greenhouse gases in climate change. Discover key insights on rising temperatures, sea level changes, and the influence of land surfaces and cloud formations.

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LEARNING FROM GLOBAL DISASTER LABORATORIES PART 11A: FUNDAMENTALS OF GLOBAL CLIMATE CHANGE

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  1. LEARNING FROM GLOBAL DISASTER LABORATORIESPART 11A: FUNDAMENTALS OF GLOBAL CLIMATE CHANGE Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA 

  2. FUNDAMENTALS OF GLOBAL CLIMATE CHANGE WHAT DO WE NOT KNOW FOR CERTAIN?

  3. THE ISSUE COULD human activities exacerbate the “unnatural” Greenhouse effect by increasing certain greenhouse gases (e.g., CO2) above normal (i.e., safe) levels; if so, can we do anything to slow or reverse the undesirable trend?

  4. THE ISSUE: HUMAN INFLUENCES • Are humans exacer-bating GLOBAL WARMING by adding too much carbon dioxide to the normal levels of greenhouse gases in the atmosphere through rapidly increasing global use of fossil fuels.

  5. HUMAN INFLUENCES • Aerosols, smoke and sulfates reflect sunlight away from the Earth, which outweigh the temporary, localized cooling effects from aerosols and the smoke and sulfates from industry.

  6. HUMAN INFLUENCES ON LAND SURFACES • Once tropical forests (a carbon sink) are cleared for cattle ranching or community development, the cleared land can becomes a major source of methane, a greenhouse gas.

  7. FUNDAMENTALS OF GLOBAL CLIMATE CHANGE WHAT DO WE THINK WE KNOW FOR CERTAIN?

  8. GCC: LITHOSPHERE-HYDROSPHERE-ATMOSPHERE-BIOSPHERE INTERACTIONS

  9. WHAT DO WE KNOW? THE EARTH’S GREENHOUSE EFFECT OCCURS NATURALLY.

  10. PLANET EARTH (THE BLUE PLANET) AND THE SOLAR INPUT

  11. PHYSICALINTERACTIONS OCCUR ON MANY DIFFERENT SCALES • Propagation, reflection, and refraction of light and EM waves radiated from the sun (i.e., the solar input to Planet Earth)

  12. WHAT DO WE KNOW? ABOUT 33 PERCENT OF THE INCOMING SOLAR INPUT IS REFLECTED BACK TO SPACE BY CLOUDS, SNOW, ICE, AND, TO A LESSER DEGREE, BY LAND AND WATER SURFACES.

  13. WHAT DO WE KNOW? THE BALANCE (ABOUT 70 PERCENT) OF THE INCOMING SOLAR INPUT IS ABSORBED BY LAND, AIR, WATER, AND ICE.

  14. WHAT DO WE KNOW? THE SOLAR SPECTRUM INCLUDES: A)VISIBLE LIGHT (ROYGBIV), ALONG WITH: B) ULTRAVIOLET LIGHT (SHORTER WAVE LENGTHS),AND C) INFRARED LIGHT(LONGER WAVE LENGTHS).

  15. PHYSICALINTERACTIONS OCCUR ON MANY DIFFERENT SCALES • Absorption, storage, and re-radiation of light and EM waves causes the “natural” greenhouse effect).

  16. WHAT DO WE KNOW? THE GREENHOUSE EFFECT OCCURS WHEN AN EARTH WARMED BY THE SOLAR SPECTRUM RADIATES INVISIBLE INFRARED LIGHT BACK, BUT…

  17. WHAT DO WE KNOW? CONTINUED …INSTEAD OF GOING BACK TO SPACE, IT IS PARTLY ABSORBED BY GREENHOUSE GASES IN THE ATMOSPHERE NOTE: ABSORPTION MAKES THE ATMOSPHERE WARMER.

  18. GREENHOUSE GASES IN THE ATMOSPHERE • “Greenhouse" gases include water vapor, carbon dioxide, methane and nitrous oxide.

  19. WATER VAPOR • Water vapor is the most potent greenhouse gas • Higher air temperatures increase the rate of water vaporization.

  20. VOLCANIC ERUPTIONS • Volcanic eruptions add water vapor and ash to the atmosphere.

  21. PHYSICALINTERACTIONS OCCUR ON MANY DIFFERENT SCALES • Absorption of heat by greenhouse gases in the atmosphere causes the “unnatural” greenhouse effect).

  22. “UNNATURAL”GREENHOUSE EFFECT • Greenhouse gases trap heat inside the atmosphere. • Too much trapped heat increases temperatures in the atmosphere and on the land and ocean surfaces, which causes climate change.

  23. WHAT DOES IT ALL MEAN? • THE “NATURAL” GREENHOUSE EFFECT KEEPS THE EARTH WARM AT ABOUT 57.9 DEGREES F, AND • THE “UNNATURAL”GREENHOUSE EFFECT CAUSES THE ATMOSPHERE’S TEMPERATURE TO RISE, FOLLOWED BY A RISE IN LAND AND OCEAN TEMPERATURES, CAUSING CLIMATE CHANGE ON A GLOBAL SCALE

  24. WHAT DO WE KNOW? SATELLITE MEASUREMENTS INDICATE THAT THE TROPO-SPHERE IS WARMING FASTER THAN THE EARTH’S SURFACE. NOTE: THIS INDICATES THAT GREENHOUSE GASES IN THE ATMOSPHERE ARE ABSORBING TOO MUCH HEAT.

  25. 2005 - HOTTEST YEAR ON RECORD • According to NASA and other organizations, 2005 was the hottest year on record for the Northern Hemisphere. • Temperatures were about 1.4 degrees Fahrenheit above the historical average.

  26. A WARMING EARTH: SEPT 25, 2007

  27. THE AVERAGE GLOBAL TEMPERATURE HAS RISEN 1.7 DEGREES F IN PAST 150 YEARS

  28. WHAT DO WE KNOW? AVERAGE GLOBAL SEA LEVEL HAS INCREASED BY 4.7 INCHES SINCE THE LAST ICE AGE.

  29. WHAT DO WE KNOW? SEA LEVEL RISES FOR TWO REASONS: WATER EXPANDS WHEN IT IS WARMED, AND WATER VOLUME INCREASES AS MELT WATER IS ADDED.

  30. WHAT DO WE KNOW? IF THE FLOATING ARCTIC ICE CAPS MELT, GLOBAL SEA LEVEL WILL NOT BE AFFECTED. IF ALL THE SNOW AND ICE IN GREENLAND MELTED, GLOBAL SEA LEVEL WILL RISE 24 FEET.

  31. CLOUDS CAUSE BOTH COOLING AND WARMING • Clouds cool Earth by reflecting incoming solar energy. • Clouds cool Earth by slowing evaporation. • Clouds warm Earth by trapping heat being re-radiated upward from the Earth’s surface.

  32. LAND SURFACES AFFECT TEMPERATURES AND MOISTURE • Mountain ranges can block clouds, creating "dry" shadows downwind. • Sloping land facilitates water runoff, leaving the land and air drier.

  33. ROLE OF ICE AND SNOW • Ice and snow reflects heat outward into space, cooling Planet Earth in the process. • When ice melts, ocean water looses some of its stored heat.

  34. THE OCEANS ARE A NATURAL CARBON SINK • The oceans and marine life remove and/or consume huge amounts of carbon dioxide.

  35. THE OCEANS STORE HEAT BETTER THAN LAND DOES • Oceans, the source of moisture in the air, store heat more effectively over the long term than land and transports it efficiently over distances of thousands of miles.

  36. WHAT DO WE KNOW? THE ALBEDO (PERCENT OF LIGHT REFLECTED) FOR FRESH SNOW IS 80-90 PERCENT, BUT IT IS ONLY 50 – 60 PERCENT FOR MELTING ICE.

  37. WHAT DO WE KNOW? CARBON DIOXIDE ENTERS THE ATMOSPHERE NATURALLY, AND IT LEAVES THE ATMOSPHERE NATURALLY.

  38. WHAT DO WE KNOW? AS THE GREENHOUSE EFFECT INCREASES, TEMPERATURES IN THE ATMOSPHERE INCREASES AND THE REMOVAL RATE OF CARBON DIOXIDE DECREASES.

  39. SUMMARY

  40. WHAT DO WE KNOW? WITHOUT THE “NATURAL” GREENHOUSE EFFECT, PLANET EARTH WOULD BE MUCH COLDER; E.G., A TEMPERATURE OF ABOUT MINUS 2 DEGREES F.

  41. WHAT DO WE KNOW? IF THE “UNNATURAL” GREENHOUSE EFFECT WERE TO GET OUT OF CONTROL, PLANET EARTH WOULD BE WARMER THAN THE CURRENT AVERAGE TEMPERATURE OF 57.9 DEGREES F.

  42. THE WORLD IS DEBATING THE TIPPING SCENARIO ISSUE • The “Tipping Scenario Issue” is: “Within a few decades, will humans be virtually helpless to slow the perceived risks associated with global climate change?

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