Climate Change: Global Warming

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Climate Change Global Warming
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Climate Change

• We are embarked on the most colossal ecological
  experiment of all timedoubling the concentration
  in the atmosphere of an entire planet of one of
  its most important gasesand we really have
  little idea of what might happen.
  Paul A. Colinvaux

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Global Warming

• Caused by Greenhouse effect,
• Natural phenomenon,
• Has always been involved in Earths climate.
• Greenhouse analogy

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Greenhouse Gases

• Greenhouse gases
• H2O
• most important, abundant
• CO2
• Methane, CH4
• Nitric oxide, NO2
• Ozone, O3
• Hydrocarbons
• Chlorofluorocarbons

• not Greenhouse gases
• Nitrogen, N2
• Oxygen, O2
• Argon, Ar
• Carbon monoxide, CO

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Greenhouse Gases
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History of Climate

• How can we know past climate?
• Data from Dome C, Antarctica, ice core
• Estimates of Temp. from hydrogen isotopes
• Measurements of greenhouse gases (CO2)
• Estimates of Temp. from oxygen-18 (fossil marine
  shells)
• Fossils (Plants, animals)

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Global Warming

• Measured and predicted increased temperature of
  atmosphere over last 100-140 years.
• Measured 0.6 C (1.1 F)
• Predicted by A.D. 2100 1.4 5.8 C
• Even at lowest estimate, Earth will be warmer
  than at any time in last 10,000 years.

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Global Warming

• Increase in greenhouse gases in Earths
  atmosphere
• CO2 up 31 since 1958
• CH4 up 151
• NO2 up 17

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Climate Change Models

• Changes in climate predicted
• predictions based on mathematical models

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Climate Change Models

• Model accuracy depends on
• Design assumptions of model,
• Accuracy of data used
• Measurements of greenhouse gases in ice cores
• Estimates of Temp. from oxygen isotopes (fossil
  shells)
• Measurements of greenhouse gases in air now
• Magnification of model error ?
• Factors in climate-system that amplify/dampen
  effects
• May not be adequately modeled
• Unexpected/Unpredicted events.

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Climate Change Models

• Amplifying/ Dampening effects
• oceans,
• clouds,
• polar ice,
• air pollution,
• plant growth,
• decomposition in wetlands,
• forest turnover
• Uncertainty in predictions remains !

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Effects of Climate Change

• Intergovernmental Panel on Climate Change, Fourth
  Assessment Report, 2007
• Noted indicators
• Global physical indicators
• Regional physical indicators
• Biological indicators
• Social indicators

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Effects of Climate Change

• Predicted physical changes
• Temperature
• Precipitation

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Effects of Climate Change

• Predicted physical changes
• Melting glaciers
• Decrease in Arctic Antarctic sea ice
• Inuit culture
• Polar bear
• Melting permafrost

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Effects of Climate Change

• Predicted physical changes
• Rise in sea level
• 10-20 cm in 20th century
• 18-60 cm more in 21st century
• Effect on Maldives
• Effect on coastal cities

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Effects of Climate Change

• Predicted biological changes
• Forests
• tropical, temperate, boreal,
• Biodiversity
• Coral reefs
• Human health
• Mosquitoes that spread malaria, yellow fever,
  dengue, etc. could live in USA.

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Effects of Climate Change

• Predicted biological changes
• Agriculture
• food production,
• Water supplies
• Weather extremes
• Storms
• Hurricanes

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Solutions ?

• International Agreements
• Framework Convention on Climate Change
• Rio de Janeiro, 1992
• Objective of stabilizing greenhouse gas emissions
• Kyoto Protocol, 1997
• 160 nations agreed to roll back CO2, methane,
  nitrous oxide below 1990 levels
• USA refused to ratify or comply
• Cost to economy
• Cost to worlds economy in future?

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Solutions ?

• USA and other countries could reduce CO2 CH4
  emissions
• Use energy more efficiently
• Mass transit
• Cut use of fossil fuels
• Shift to nuclear ??
• Solar, wind energy
• Restore protect forests, wetlands, etc.
• Control population growth.