CLIMATE SYSTEM AND WEATHER

WEATHER Weather refers to: The state of the atmosphere in a particular place and time. Weather occurs over short time periods. The weather predictions usually cover days or weeks.

TYPES OF WEATHER What terms do you associate with weather?

ALBEDO = REFLECTION How much is reflected? Scale is 0-1 White =1, High reflectivity Black = 0 Low reflectivity What do you think? High or low albedo? Grass Ice Rocks Asphalt Concrete

ALBEDO = REFLECTION

OPTIONAL VIDEO ated Begin at 1:50. Researcher out on the ice, measuring albedo.

CLOUDS Clouds reflect sunlight and need to be included in the energy budget Low thick clouds = high reflection, cools the surface High thin clouds = lower reflection and other things warms the surface

Sun emits radiation Earth intercepts sunlight Input = Sunlight on one side of Earth 30% is reflected

WHAT TYPES OF AREAS OF EARTH HAVE - A HIGH ALBEDO? - A LOW ALBEDO? (THINK URBAN, FARMLAND, DESERT, ETC.)

EARTH’S ALBEDO Collected by NASA satellite and averaged. Does not include the ocean and no data for white areas.

IF THE AMOUNT OF ENERGY THAT COMES IN TO EARTH IS THE SAME AMOUNT OF ENERGY THAT GOES OUT OF EARTH, HOW CAN OUR PLANET STAY WARM? 11

COMPOSITION OF THE EARTH’S ATMOSPHERE Nitrogen N 2 = 78 % Oxygen O 2 = 21 % Argon Ar = 0.9 % Other = <0.1% Carbon Dioxide CO 2 Methane CH 4 Nitrous Oxide NO 2 Ozone O 3 Hydrogen 12

GREENHOUSE GASES 13 Carbon Dioxide Water Methane Nitrous Oxide Ozone

THE “GOLDILOCKS” PRINCIPLE 14 Mars is too cold, Venus is too hot, and Earth is just right!

WHAT IF EARTH DID NOT HAVE GREENHOUSE GASES? Main Greenhouse Gases CO 2 and H 2 O Estimated temperature without greenhouse gases -5 °C (23 °F) Actual average temperature 15 °C (59 °F) Temperature change because of greenhouse gases 20 °C (36 °F) 15

ALBEDO POSITIVE FEEDBACK LOOP different surfaces have different level of reflectivity Ice reflects more light than other substances Snow reflects 95% of radiation The water under the ice can absorb large amounts of heat energy, which could increase temp of water and cause more melting

CLIMATE CHANGES IMPACT: which, in turn, impact:

SEA-LEVEL RISE HEAVILY POPULATED DELTA REGIONS THAT ARE VULNERABLE TO SEA LEVEL RISE Image: idrc.ca IMPACTS ON COASTAL AREAS

WHAT ABOUT THE BAY AREA? Sea level rise is an important consequence in coastal areas like the Bay Area

Muir Glacier, Alaska NSIDC/WDC for Glaciology, Boulder, compiler. 2002, updated Online glacier photograph database. Boulder, CO: National Snow and Ice Data Center. August 1941August 2004 Shrinking Glaciers Preponderance of Evidence Resource Card 20

Source: Westerling et al Western US area burned Increasing Wildfire Risk Preponderance of Evidence Resource Card 21

AVERAGE SURFACE TEMPERATURE CHANGES Average Surface Temp in vs Preponderance of Evidence Resource Card 22

IPCC, 2007 INCREASING CO 2 CONCENTRATION Preponderance of Evidence Resource Card 23

Source: Hansen, Clim. Change, 68, 269, ICE CORE RECORDS Time (years) CH4 (ppb) CO2 (ppm) Preponderance of Evidence Resource Card 24

UCS PROJECTED CHANGES IN CA SUMMER TEMPERATURE Preponderance of Evidence Resource Card 25

2004 >9,500 ft 1900 >7,800 ft Pika Species Shifting Species that are sensitive to temperature conditions can only move up the mountainside as conditions get too warm for them lower down. In the Sierras, Pika were seen at 7,800 feet and above in By 2004, they were not seen below 9,500 feet. This trend is expected to continue. The mountains rise as high as 12,000 feet, but the rocky hillsides where Pika live do not reach that high. Preponderance of Evidence Resource Card 26

Diminishing Sierra Snowpack Percentage Remaining, Relative to UCS Preponderance of Evidence Resource Card 27