Global Warming - So What

download Global Warming - So What

of 64

Transcript of Global Warming - So What

  • 8/14/2019 Global Warming - So What

    1/64

    Global Warming

    So What?.

    July 2009 .

  • 8/14/2019 Global Warming - So What

    2/64

    Droughts Worsen .

    Droughts Worsen.

    Deserts Spread.

    The Culprit? . ..

    Damages from our emissions so farwill intensify fordecades to come.

    The more stuff we put in the airnow,

    the fasterthe damages worsen and

    the worse they eventually get.

    Evaporation

  • 8/14/2019 Global Warming - So What

    3/64

    The Way It Is .

    We are already experiencing

    dangerous human interference in the climate system:

    increased incidents of heat waves, of floods, of droughts,

    of intense tropical storms, of accelerated sea level rise.

    The issue now is whether we can avoid

    catastrophic human influence on the climate system.

    I believe we still have a good shot at

    avoiding catastrophic interference.

    I sometimes say that the situation we are in is like

    driving a car with bad brakes toward a cliff in the fog.

    President Obamas Science Adviser .

    John Holdren, April 8, 2009 .

  • 8/14/2019 Global Warming - So What

    4/64

    Oil Imports

    Oil has become expensive; it stayed above $80 a barrel for months.

    Gasoline last year topped $3 a gallon for months in the US.

    The US imports 60% of its oil.

    Thats up from 53% in 2000, when George W. Bush took over,

    and 38% when his father took office.

    The US imports twice as much oil as any other nation uses.

    Texas uses 3.1 times as much oil as it pumps out,

    Louisiana 4.1 times as much.

    US oil production peaked in 1970. World oil use outpaces oil found by 3:1 each year, and rising.

    World oil production is peaking over 2005-10.

    The era of cheap gasoline in America is over.

  • 8/14/2019 Global Warming - So What

    5/64

    Greenhouse Effect

    Greenhouse gases in the

    air (GHGs) intercept some

    outgoing radiation andre-radiate it back down.

    This warms Earth more.

    More GHGs = warmer still.

    Dark Earth absorbs sunlight.

    Earth warms up and

    radiates heat.

    Light surfaces reflect sunlight. Those surfaces dont warm Earth much.

    Changing a light surface (ice) to a dark one (water) warms Earth.

    Changing a dark surface (forest) to a lighter one (desert) cools Earth.

    Cyclic changes in solar output have warmed and cooled Earth modestly.By now,human GHGs warm Earth much more than solar changes do.

  • 8/14/2019 Global Warming - So What

    6/64

    Greenhouse Gases

    GHGs warm Earth by 32C (58F).

    Earth would average 0F without them. Watervapor (H2O) does 2/3 of this warming.

    But H2O stays up for only 2-3 weeks, on average.

    Concentrations vary many-fold over time and space.

    As Earth warms up, evaporation increases H2O in the air.This amplifies warming from other GHGs considerably. So,

    scientists often treat H2O not as a GHG, but a feedback for other GHGs.

    Carbon dioxide (CO2) does 55% of the remaining net warming.

    Almost all US CO2 comes from burning coal, oil & natural gas.Per unit of energy, coal emits 4 units of CO2, oil 3, natural gas 2.

    Methane (CH4, natural gas) does 16%.CH4 comes from wetlands, cows, rice, landfills, coal mines.

    CFCs (old air conditioners, ozone hole) do 11%,

    Nitrous oxide (N2O - fertilizers) does 5%, black soot most of the rest.

    ozone (O3) 10%, net.

  • 8/14/2019 Global Warming - So What

    7/64

    Vostok Ice Core Data

    Vostok Ice Core DataFor hundreds of

    thousands of years,

    temperatures havetracked the levels of

    GHGs CO2 and CH4

    in the air.

    The difference

    between 190 and 280ppm of CO2 was

    10C (18F) and

    ice almost a mile deep

    covering Chicago.

    Thousand Years before PresentVimeux, Cuffey & Jouzel,Earth and Planetary Science

    Letters 203: 829-843 (2002)

    + 2006 temperature

    ppm = parts per million ppb = parts per billion

  • 8/14/2019 Global Warming - So What

    8/64CO2 Levels in the Air

    So far, half the CO2 we emited has stayed in the air.

    The rest has gone into carbon sinks

    But oceancarbon sinks are fading.

    The difference between 280 and 380 ppm of CO2 remains to be seen.Weve seen some of it so far.

    300 ppm (maximum between ice ages)

    AnnualAverages

    Up38%

    Accelerationbegan.

    Disappearing forests weaken another sink.

    But much of the effect is delayed. It materializes slowly.

    - into oceans, trees, soils, rocks.

  • 8/14/2019 Global Warming - So What

    9/64

    Sun vs Temp

    - NASA

    - World Radiation Center

    Watts / m2 C

    Solar Irradiance at Earth Orbit, Annual Average

    In 2007, solar output was the lowest yet recorded (in 28 years), but

    Earths air temperatures (land surface) were the highest yet recorded.

    Global AirTemperature, Land Surface, 3-Year Moving Average

  • 8/14/2019 Global Warming - So What

    10/64

    Clouds

    Halfthe sunlight reaching our atmosphere makes it to the surface.

    Barriers include blue sky (not black),

    Clouds Clouds reflect some sunlight away, cooling Earth.

    They also keep outbound heat in, warming Earth, esp. at night.

    Low clouds cool Earth more than they warm it.

    High clouds do the reverse.

    Clouds cover a little more than half of Earth.

    On balance, they cool Earth.

    Changes in cloud cover affect global temperature.

    So do changes in % high clouds vs low clouds.

    Many factors affect cloud formation & distribution.

    At night & going up over mountains, air cools.

    Cool air holds less H2O, so it will often cloud up & rain.

    clouds, haze & the ozone layer.

  • 8/14/2019 Global Warming - So What

    11/64

    Sulfates& Cooling

    Dark sulfates in the air block sunlight.

    Sulfates make haze

    More sulfates= cloudier = cooler.

    Most sulfates come from burning coal,

    SO2 goes up the smokestacks.

    GHGs stay in the air many years,

    GHG levels keep rising.

    Sulfates currently offset 40% of warming from human GHGs.

    It changes to SO4 (sulfate) up in the air.

    That cools Earth.

    Sulfate levels dont.

    sulfates usually for days.

    some from volcanoes.

    &become cloud condensation nuclei.

  • 8/14/2019 Global Warming - So What

    12/64ulfate Cooling Un-Smooths GHG

    warmingunmasked

    majorcooling

    cool

    NASA GISS - Earths7,000 weather stations

    - adjusted for urban

    heat island effects

    Sulfates up 52%.

    Sulfate Levels in Greenland Icemilligrams of Sulfate per Ton of Ice

    40

    Krakatoaerupts

    ElChichn

    Mt.Pinatubo

    Sulfate Cooling Un-Smooths GHG WarmingC

    cool

    sulfates still3x 1880 levels

    WW I:more SO2

    up the stacks

    WW II:more SO2

    1880 2000

    GreatDepression

    JFK-LBJExpansion:

    more SO2

    USSO2cuts start

    Sulfates

    fall 13%.

    Soufriere,S Maria,

    Pelee erupt

    cool

    61 891920

    77 1161960

    162 118CoolingoffsetsGHG

    warming.

    Sulfates up 46%.

    cool

    cool

    Brown .cloud .growsover .India, .China. .

    cool

    cool

    (Intergovernmental Panelon Climate Change, 2002)

    cool

    cool

    warmingless SO2

    up the stacks

    Sulfatesup110%.

    1900

    Colimaerupts

    cool

    Agungeruptscooler

    Katmaieruptscooler

  • 8/14/2019 Global Warming - So What

    13/64

    Land warms more (faster) than oceans.

    It warms more when & where its coldest:

    in winter,

    at night,

    & especially

    toward the poles.

  • 8/14/2019 Global Warming - So What

    14/64

    Earth Is Heating Up. Earth now absorbs 0.5% more energy than it emits - .

    a 435 million MW heat gain435 million MW

    This absorption has been accelerating, from near zero in 1960.

    Airat the land surface is 1.0C warmerthan 100 years ago.Half that warming happened in the last 25 years.

    Another0.6Cwarming (so far) is in the pipeline.

    Earth will warm another 0.6C,

    Air at the sea surface is 0.8C warmerthan 100 years ago.

    The oceans have gained ~10 x moreheat in 40 years

    than ALL the energy humans have EVER used.

    One MW can power several hundred US homes.~ means approximately, roughly, is about equal to

    = 30x human energy use.

    1C = 1.8F.

    That is,

    (75 million MW)

    OurGreenhouse effect intensifies.

    =100 x globalelectric supply

    so it emits enough heat to balance absorption.

  • 8/14/2019 Global Warming - So What

    15/64

    The Tipping Points Report to US & British Legislators - January 2006

    in the US, to Senator Olympia Snowe (R-ME)

    What would make climate change accelerate,

    so natural forces defeat our efforts to slow it?

    1 Disappearance of sea icemeans more heat is absorbed by the water below.

    2

    Carbon sinks fade & failin oceans & forests.

    3 Methane release from permafrost

    revs up warming in a vicious circle.

  • 8/14/2019 Global Warming - So What

    16/64

    More Heat - So?Hurricanes convert ocean heat to powerful winds & heavy rains.

    Intense hurricanes are becoming more common.

    Higherhurricane energy closely tracks sea surface warming.

    With more carbon, oceans have grown more acidic.

    Warmerwater holds less dissolved oxygen.

    Oceanswarmed 0.15C over 1997-2004, so

    Warming was far strongest in the N Atlantic.

    Water

    North Atlantic Hurricane Activity

    0.3

    0.5

    0.7

    0.9

    1.1

    1.3

    1.5

    1945 1955 1965 1975 1985 1995 2005

    Total Energy from Hurricanes / Year(Divided by Adjusted Baseline)

    September Sea Surface Temperature(C - Baseline)

    Emanuel, 2005

    Percentage of Hurricanes, by Intensity

    10%

    20%

    30%

    40%

    50%

    1972 1977 1982 1987 1992 1997 2002

    5-Year Averages

    Category 1

    Categories 2-3

    Categories 4-5

    weakest

    strongest

    Webster, 2005

    All Ocean Basins Combined East of Caribbean, west of Africa6-18N, 20-60W

    Shells dissolve easier.

    Fish & mollusks suffer.

    planktonabsorbed 7% less CO2.

    CO2 uptake there fell by half.

  • 8/14/2019 Global Warming - So What

    17/64

    Reservoirs in the SkyMountain glaciers and snowpacks

    are dwindling ever faster.

    Himalayan glaciers may vanish by 2035,

    & with them

    the Ganges River in the dry season,

    the Indus River too, the Yellow River maybe.

    Mountain snows melt earlier.

    Californias San Joaquin River (Central Valley, US salad bowl)

    could dry up by July.The Colorado and Rio Grande too?

    The Colorados 10-year drought is the worst since white men came.

    Lake Mead water levels dropped 60 feet from 2000 to 2003.

    50% chance its functionally dry by 2021. .

  • 8/14/2019 Global Warming - So What

    18/64

    Earths ThermostatGreenlandsice-melt rate rose150%over the past decade.

    Its net melt-water already ~ US wateruse.

    Arctic Oceaniceis shrinking fast.2007s minimum ice area was 20% below 2005s record.

    Thats down 40% in 25 years.

    In 2008, icepack volume was the lowest on record,

    The icepack could melt away by fall in ~ 10 years

    West Antarcticasnet ice-melt is ~ half of Greenlands.

    Its smaller ice shelves, along the Antarctic Peninsula, are breaking up.

    Sea level could rise more than 3 feet, in this century alone.

    Thawing permafrost holds 2-4 xMOREcarbon than ALL the carbon

    humans have EVER emitted.

    Thawing permafrost will likely add 50-100ppm of CO2 to the air by 2100.

    Frozen subsea methane hydrates hold even more carbon.

    The Arctic Ocean has begun emitting big burps of methane.

    Permafrost area shrank 7% from 1900 to 2000.

    ice area the 2nd lowest.

    and be gone all summer in ~ 50.

  • 8/14/2019 Global Warming - So What

    19/64

    What Else?From 1979 to 2005, the tropics spread &

    the sub-tropicarid belts grew ~140 miles toward the poles,

    a century ahead of schedule.Forestfires now burn 6 x as much area / year as before 1986.

    Severe drought hit 45% of North America in 2002,

    so plants absorbed 50% less CO2.

    Canadas forests recently turned into a net carbon source.

    The Amazons 2005 drought was the worst in years,so the rainforest temporarily became a carbon source.

    Australias 7-yeardrought is the worstin many centuries.North China & Argentinas Pampas now suffer 50-yeardroughts.

    In 2007, a 100-yeardrought hammered Atlanta & the whole Southeast.

    Californias 3-yeardrought is an official emergency.

    In 2006-7, Los Angeles rainfall was the lowest on record.

    Droughts

  • 8/14/2019 Global Warming - So What

    20/64

    Is That All?No ..

    Over the last 13 years, desertsgrew from 18 to 27% of Chinas area.

    With more evaporation & irrigation,

    many water tablesfall .

    Remember the Ogalalla! .

    Since 1985, halfthe lakes in Qinghai province (China) vanished.92% in Hebei (around Beijing).

    Irrigation wells chase waterever deeper.

    Water prices rise.

    Inland seas and lakes dry up & vanish, for example:

    the Aral Sea, Sea of Galilee, Lake Chad (Darfur), Lake Eyre.

    More riversfail toreach the sea:

    - the Yellow, Colorado, Indus, Darling Rivers so far.

    Water

    3-20 feet / year.

    (aquifer under the Great Plains)

  • 8/14/2019 Global Warming - So What

    21/64

    Turning Wheat into Cactus

    In 2005-6, the Union of Concerned Scientists calculated how climate

    would change for 9 Northeast and 6 Great Lakes states in 2 scenarios:

    #1 - a transition away from fossil fuels, or

    #2 - continued heavy reliance on them (business as usual emissions).

    By 2085,

    averaged across 15 states, the climate change would be like

    moving 330 miles to the SSW (coal & oil use dwindle), or

    moving 650 miles to the SSW (heavy coal & oil use).

    Consider central Kansas, heart of wheat country.

    330 miles to the SSW lies the area from Amarillo to Oklahoma City.650 miles to the SSW lies the area around Alpine & Ft. Stockton, Texas.

    2 people / square mile. Cactus grows there.

    Mesquite & sagebrush too.

    No wheat

  • 8/14/2019 Global Warming - So What

    22/64

    UN Chief on Climate Change

    Some scientists are saying publicly that if humanity

    goes on with business as usual, climate change could

    lead to the collapse of civilization, even in the lifetime

    of today's children.

    United Nations Secretary General Ban Ki-Moon said I

    think that is a correct assessment. He added carefully Ifwe take action today, it may not be too late.

    September 24, 2007

  • 8/14/2019 Global Warming - So What

    23/64

    By 2059, Once a Century Drought Can Cover 45% of Earth.

    1969Supply-Demand Drought Index

    1999.

    Business

    as UsualEmissions

    2029 2059

    DRY WET

    0 1 5 16 36 36 16 5 1 0

    % Occurrence in Control Run

    in 20592 x CO2

    Fig. 1 in David Rind, R. Goldberg, James Hansen, Cynthia

    Rosenzweig, R. Ruedy, Potential Evapotranspiration andthe Likelihood of Future Droughts, Journal of GeophysicalResearch, Vol. 95, No. D7, 6/20/1990, 9983-10004.

    Climate Model:NASA

    GoddardInstitute for

    Space Studies(GISS)

    +4.2C+14% rain

  • 8/14/2019 Global Warming - So What

    24/64

    Projected Droughts by Year .

    Fig. 2 in Rind et al., 1990

    0

    10

    20

    30

    40

    50

    60

    70

    1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

    Occure

    nce(%)

    Dry

    Drought

    Extreme Drought

    16%

    5%

    1%}Occurrence in Control Run

    Over 2000-04, the average frequencies are 18% for Drought and 33% for Dry.

    A weighted average for as dry as 11% of the time drought is ~ 27%.

    Based on Supply-Demand Drought Index

    2x

    CO2

    2xCO2

    Once a century drought can cover 45% of Earths land by 2059.

    Projected Drought ConditionsLand Surface, except Antarctica

    June-August, Business as Usual Emissions

  • 8/14/2019 Global Warming - So What

    25/64

    Thanks for the crystal ball.

    BUT

    Is any of this actually happening? .

    Remember

    forest fires, falling water tables,disappearing lakes and rivers,

    spreading deserts?

    (Please also remember11% of the time drought was projected to

    increase to 27% of the time over 2000-2004.)

    Now for the BIG PICTURE

    YES.

  • 8/14/2019 Global Warming - So What

    26/64

    Droughts Are Spreading Already.

    Very Dry Areas - % of Global Land Area, 60S - 75N .

    -5

    0

    5

    10

    15

    20

    25

    30

    1950 1960 1970 1980 1990 2000

    %w

    ithSevere

    orExtremeDrou

    ght-

    .

    PalmerDrough

    tSeverityIndex