Global Climate Change

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Global Climate Change

• Warming of the climate system is unequivocal.
  International Panel on Climate Change, Fourth
  Report

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Outline

• The Atmosphere and Climate
• Convection Currents
• Greenhouse Effect
• Weather
• Winds
• Frontal Systems
• Cyclonic Storms
• Climate
• El Nino
• Climate Change
• Kyoto Protocol

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The Atmosphere and Climate

• Weather - daily temperature and moisture
  conditions in a place
• Climate - a description of the long-term weather
  pattern in a particular area

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The Atmosphere and Climate

• Troposphere
• Ranges in depth from 18 km over the equator to 8
  km over the poles.
• All weather occurs here.

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The Atmosphere and Climate

• Stratosphere
• Very stable, calm layer of the atmosphere.
• Used by aircraft.
• From tropopause up to about 50 km
• Has almost no water vapor, but 1000X more ozone
  than the troposphere
• Ozone absorbs ultraviolet light, which warms
  upper part of stratosphere.
• Ozone protects all life on Earth since UV
  radiation damages living tissues.

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The Atmosphere and Climate

• Mesosphere
• Middle Layer
• Thermosphere
• Aurora borealis (northern lights)

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Layers of the Atmosphere
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Energy and the Greenhouse Effect

• Solar Radiation
• Of solar energy reaching outer atmosphere
• 25 reflected
• 25 absorbed
• 50 reaches earths surface
• Of the solar energy that reaches the surface,
  much is reflected (albedo)
• Fresh clean snow 90
• Dark soil 3
• Net average of earth 30

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Energy and the Greenhouse Effect

• Most solar energy reaching the Earth is near
  infrared (short wavelength).
• Energy reemitted by the earth is mainly far
  infrared radiation (long wavelength, heat)
• Longer wavelengths are absorbed in the lower
  atmosphere, trapping heat close to the earths
  surface.
• Greenhouse Effect
• Atmosphere transmits sunlight while trapping heat.

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Greenhouse Effect

• Gases in the atmosphere, especially carbon
  dioxide and water vapor, are the substances that
  retain heat.
• Burning fossil fuels releases extra carbon
  dioxide.
• Deforestation destroys carbon sinks.
• Positive feedback loop - poles covered with ice
  reflect solar radiation back into space. Now
  that ice is melting, open water is absorbing more
  heat, which in turn is melting more ice, leading
  to more warming.

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Sources of Greenhouse Gases

• Carbon Dioxide - fossil-fuel burning
• Atmospheric levels increasing steadily
• Most important cause of warming
• Methane - ruminants, rice paddies
• Absorbs more infrared than CO2 .
• Chlorofluorocarbons (CFCs) - refrigerants
• Declined in developed countries, but now produced
  in developing nations.
• Nitrous Oxide - burning organic material

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Sources of Greenhouse Gases

• U.S. has less than 5 of worlds population but
  produces 28 of carbon dioxide.
• China, with 1.3 billion people, is second.
• Japan and Europe produce half as much carbon
  dioxide per person as the U.S.

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Measuring Carbon Dioxide in the Atmosphere

• There is a carbon dioxide detector in Mauna Loa
  in Hawaii.
• This allows measurements far away from cities and
  forests.
• The winds over Mauna Loa have come thousands of
  miles across the Pacific Ocean, swirling and
  mixing as they traveled.

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Measuring Carbon Dioxide in the Atmosphere

• Keelings first measurement, in March of 1958,
  was 0.0314 percent.
• Slightly higher in the winter.
• Slightly lower in the summer.
• Why? Photosynthesis
• These levels have rose steadily over the last 50
  years.

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Carbon Dioxide Concentrations on Mauna Loa
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Weather Happens

• Weather - physical conditions in the atmosphere
  (humidity, temperature, air pressure, wind and
  precipitation) over short time scales
• Rain
• Air cools as it rises, and water condenses as air
  cools.
• Cooling occurs because pressure decreases as air
  rises.
• Condensation nuclei (tiny particles) must also be
  present to have precipitation.

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Ocean Currents

• Warm and cold ocean currents strongly influence
  climate conditions on land.
• As surface water moves, deep water wells up to
  replace it.
• Ocean circulation also driven by differences in
  water density due to temperature and saltiness of
  water

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Frontal Weather

• Cold Front - boundary formed when cooler air
  displaces warmer air
• Cold air is more dense, thus hugs ground and
  pushes warm air up.
• Warm Front - boundary formed when warm air
  displaces cooler air
• Warm air is less dense and slides over cool air,
  creating a long wedge-shaped band of clouds and
  precipitation.

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Cyclonic Storms

• When rising air is laden with water vapor, latent
  energy released by condensation intensifies
  convection currents and draws up more warm air
  and water vapor.
• Storm cell will exist as long as temperature
  differential exists.
• Hurricanes (Atlantic)
• Katrina in 2005 caused greatest natural disaster
  in North American history.
• Typhoons (Western Pacific)
• Cyclones (Indian Ocean)

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Cyclonic Storms

• Tornadoes - swirling funnel clouds
• Generated by supercell frontal systems where
  strong dry cold fronts collide with warm humid
  air
• Greater air temperature differences in the
  spring, thus more tornadoes
• Downbursts - disorganized supercells that cause
  downdrafts and straight line winds

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Cyclonic Storms
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Studying Climate

• Ice cores - collected from glaciers reveal light
  and dark bands caused by annual snow accumulation
  on glacier
• Gas bubbles can be analyzed for atmospheric
  composition.
• Ash and sulfur deposits correlate with volcanic
  eruptions.
• Vostok ice core gives us a record back 420,000
  years.

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Climate

• Data show that
• Abrupt climatic change has catastrophic effect on
  living things as organisms are unable to adjust
  before conditions exceed their tolerance limits.
  Species may become extinct.
• There is a close correlation between carbon
  dioxide concentration and temperature of the
  atmosphere allegedly.

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CLIMATE CHANGE IS A NATURAL PROCESS

• Changes in climate have been observed throughout
  history.
• There have been at least 5 major ice ages.
• The sun undergoes cycles where it releases
  different amounts of energy.
• The Earths orbit can shift and tilt.
• Example Magnitude 8.8 earthquake in Chile
  shorted the Earths day by 1.26 millionths of a
  second.

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Climate

• Milankovitch Cycles - periodic shifts in Earths
  orbit and tilt which change distribution and
  intensity of sunlight
• Ice cores show drastic changes may have occurred
  over short periods of time (years to decades).
• Volcanic eruptions can cool planet suddenly.

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Milankovitch Cycles
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Evidence of Global Warming

• According to the EPA, the global surface
  temperature has increased 0.9F since 1880.
• The Earths surface is currently warming at a
  rate of about 0.29ºF/decade or 2.9F/century.
• The eight warmest years on record (since 1880)
  have all occurred since 2001, with the warmest
  years being 2005 and 2010.
• Arctic temperatures have increased twice as fast
  as the rest of the Earth.
• Source http//epa.gov/climatechange/science/rece
  nttc.html

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Global Warming

• Range of temperature increase predicted to be
  from 1.1 to 6.4C (2 to 11.5F) by 2100 depending
  on population growth, energy conservation, etc.
• Best estimate is 1.8 to 4C (3.2 to 7.8F)
• To put that in perspective, there has been a 5
  degree C rise since the middle of the last ice
  age (about 20,000 years ago).

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Global Warming

• Most people will experience more extreme weather
  including droughts, floods, heat waves and
  hurricanes. These extremes have increased
  significantly in the last decade.
• In the worst outcome, we could see millions of
  human deaths.
• Sea levels are projected to rise 17-57 cm (7 to
  23 in). If we do nothing, Greenlands ice will
  melt and raise sea levels 20 ft.

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Global Warming

• If Greenlands ice melts, a great deal of land
  will be flooded including
• Most of Florida
• Some of the Gulf Coast
• Most of Manhattan
• Shanghai
• Hong Kong
• Tokyo
• Opponents say cuts in greenhouse gas emissions
  are too costly to business.

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Is Global Warming Human-Caused?

• The Intergovernmental Panel on Climate Change
  (IPCC) released its fourth report in 2007.
• Two important statements are made in the summary
  of this report
• Warming of the climate system is unequivocal, as
  is now evident from observations of increases in
  global average air and ocean temperatures,
  widespread melting of snow and ice, and rising
  global average sea level. 

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Is Global Warming Human-Caused?

• Second statement of the IPCC fourth report
  summary
• "Most of the observed increase in global average
  temperatures since the mid-20th century is very
  likely due to the observed increase in
  anthropogenic greenhouse gas concentrations."

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Global Warming Timeline

• 19th century Beginning of industrial revolution
• 1958 Daily records of carbon dioxide levels
  start.
• Venus found to have surface temperatures above
  boiling point.
• 1970 First Earth day.
• 1973 Arab embargo -- energy crisis.
• 1977 Scientific opinion converges on global
  warming as the major climate risk.
• 1981 Warmest year on record.
• 1995 Reports on breaking up of Antarctic ice
  shelf.
• 1997 Kyoto protocol established.
• 1998 Strong El Nino produces warmest year on
  record.
• 2003 Deadly European heat wave / major ice
  sheets collapse

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2005

• Kyoto treaty goes into effect (not ratified
  by U.S.)
• Most active hurricane season in recorded
  history.
• Hurricane Katrina hits New Orleans.

Source NOAA
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Hurricane Katrina

• Formed over the Atlantic in August of 2005.
• Crossed Southern Florida as a category 1
  hurricane.
• Strengthened very quickly over warm waters of the
  Gulf of Mexico
• Made landfall over Louisiana as a Category 3
  hurricane.

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New Orleans

• Parts of New Orleans are below sea level.
• The levees holding back the Mississippi river and
  the shoreline were not maintained properly.

• Immediate connections were made between global
  warming, the unusually warm Gulf of Mexico, and
  the hurricane.

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2007-Present

• Severe drought hits Australia from 2007-2009,
  followed by severe flooding in 2010.
• Severe flooding in Pakistan in 2010.
• In the last stages of President Bushs term,
  global warming was emphasized as a scientific
  uncertainty
• In 2009, the U.S. House of Representatives passed
  a bill meant to gradually limit the amount of
  carbon dioxide produced. Stalled in the Senate.
• In 2009, a series of emails from the researchers
  at the University of Anglia were made public
  some implied data was being manipulated. This
  was nicknamed Climategate.
• 2010 ties 2005 for the warmest year on record.

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Evidence of Climate Change is Overwhelming

• Ave. global temperature climbed 0.6C (1F) in
  last century.
• 19 of 20 warmest years in the past 150 yrs have
  occurred since 1980.
• Hottest year since temperature records were begun
  was 2005.
• Poles are warming fastest (4C, 7F over past 50
  years). Permafrost is melting in Alaska and
  Canada and houses, pipelines and trees are being
  toppled.

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Global Warming Effects on Poles

• 99 of sheet ice is located in Antarctica and
  Greenland
• Ice is melting worldwide, but especially quickly
  at the poles.
• As a result
• Ocean levels have risen about 3.0mm per year in
  the 10 years.
• Adelle penguin population is down to 1/3 its
  normal level.
• Multiple populations of polar bears are declining.

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Global Warming Effects on Glaciers

• Only about 1 of the worlds sheet ice is located
  in temperate (non-polar) regions, but these are
  close in proximity to human populations.
• Himalayan glaciers are the sources of Asias
  biggest rivers
• Biggest single source of water for the entirety
  of southern Asia.

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Effects on the Hydrologic Cycle

• Surface temperatures are measurably increasing.
  This effects the water cycle
• Higher rate of evaporation (from land and sea
  both)
• Warmer atmosphere is capable of holding more
  water vapor.
• Higher likelihood of heavy precipitation (both
  rain and snow) weather events.
• Ocean temperatures are also increasing.

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Flawed Predictions

• A statement was published by a journal that
  suggested the Himalayan glaciers could be melted
  by 2035.
• These numbers were based on unrealistic
  calculations and this prediction was retracted.
• Many dismiss global warming claims in general as
  a result of retractions such as this.

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Global Warming will be Expensive

• At present, reducing greenhouse gas emissions
  would cost 1 of world GDP according to Stern
  report. (IPCC report says less than that.)
• Energy production will need to be 80
  decarbonized by 2050 to stabilize climate.
• Ethical issue
• Poor will suffer the most at least 200 million
  people will become refugees of flood and drought.

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Steps For Combating Climate Change

• Emissions trading
• markets already exist
• Technology sharing
• Reducing deforestation
• Helping poorer countries adapt to climate change
• Tropical areas will not change as much as middle
  and high latitudes.
• If both Greenland and Antarctica melt, 1/3 of
  Earths population will be displaced.
• - South Pacific island nation of Tuvalu already
  abandoned due to climate change

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Combating Climate Change

• Insurance companies have 2 trillion in insured
  properties along U.S. coastlines at risk from
  flooding or severe storms.
• Infectious diseases will increase as insects that
  spread them are able to move to places where
  they could not live before.
• West Nile, malaria, and dengue fever have
  appeared in North America.
• Melting of permafrost may release stores of
  methane hydrate. Uncertainty about whether that
  would increase warming or cooling.

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Controlling Greenhouse Emissions

• Reducing carbon dioxide levels
• Renewable energy sources
• Double average fuel economy
• Switch to efficient lighting and appliances
• Wind turbines
• Biofuels
• Capture and store carbon dioxide
• Planting vegetation
• Injection into wells

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Carbon Management

• Capturing and storing carbon dioxide
• Build trees in which calcium hydroxide solution
  would absorb carbon dioxide
• Plant forests
• Fertilize the oceans with iron to permit
  phytoplankton growth, which would take up carbon
  dioxide
• Inject carbon dioxide underground or in ocean

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Synthetic Trees that Capture Carbon Dioxide
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Other Ideas?

• The stratoshield is an idea developed to combat
  global warming by blocking some of the sunlight
  entering the Earths atmosphere.
• Inject sulfur dioxide or particulate pollutants
  into the stratosphere.
• This would be too high in the atmosphere to be
  directly breathed or cause acid rain.
• Blocks out just enough sunlight to bring global
  temperatures down to acceptable ranges.

Another quick solution dropping ice cubes into
the ocean. Source Futurama Crimes of the Hot
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Progress Made

• United Kingdom has rolled back its CO2 emissions
  to 1990 levels and is aiming for a 60 reduction
  by 2050.
• Germany has reduced CO2 by 10.
• Denmark gets 20 of its electricity from
  windmills, and plans to increase that to 50.
• China reduced its emissions 20 between 1997 and
  2005.
• (At its present rate, U.S. will be 25 above 1990
  emissions in 5 years. No progress.)