Climate Change Impacts in the Gulf Coast

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Climate Change Impacts in the Gulf Coast

• Philip B. Bedient
• Civil Environmental Engineering
• Rice University

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Climate Change History

• Earths climate has always been changing
• Ice age (2 m.y.a.), glacial periods, polar ice
  caps
• 18,000 yrs ago cold spell continental glaciers

• Last 100 yrs, surface has warmed about 0.6C
• In past 10,000 yrs, global temp. has never varied
  more than 1.5C

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Why has it been changing?

• Various theories
• Intricate complex relationship b/w ocean,
  atmosphere, ice, and other elements
• No climatic element in systems is isolated
• Influences path of ocean currents, transport of
  heat, global wind system, and climates

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Key Predictions for Future

• Increased warming
• 5-9F increase next 100 yrs
• Differing regional impacts
• Vulnerable ecosystems
• Widespread water concerns
• Secure food supply
• Near-term forest growth increase
• Damage in coastal/permafrost areas
• Adaptation determines health

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Greenhouse effect

• Delicate balance of incoming outgoing energy in
  earth-atmosphere
• Atmosphere gases (water vapor, CO2, CH4,
  halocarbons, O3) absorb Earths heat
• Radiate some heat back to Earth, some passes
  through into space
• Humans change atmosphere
• burn coal, oil, natural gas, destroy forests
• CO2 risen 30, CH4 150 in past 100 yrs
• Heat energy cant pass into space

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Increasing Greenhouse Gases

• Unusual rapid warming of 0.6C in 20th century
• Human activities major cause of warming
• Carbon emissions have increased from 1 to over 7
  billion metric tons/year
• Lifetimes of gases last centuries
• CO2 Predicted to triple by 2100

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Climate Assessment Tools

• Historical records climate simulations
• General Circulation Model (GCM)
• model Earths climate
• incomplete, but still state-of-science
• Two main models- Hadley Canadian

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Hadley Canadian Models

• Principles driving models are similar
• Differ in representation of effects of important
  processes
• Thus, different views of 21st century climate
• Hadley predicts wetter climate
• Canadian predicts greater temp increase
• Uncertainties
• how to represent clouds precipitation
• how emissions of greenhouse gases will change

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Past Future Temperature Change
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Precipitation Change

• Large increases in 20th century (5-10)
• Due to frequency intensity growth
• Increasingly frequent heavy precipitation events
  in 21st century

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Soil Moisture

• Critical for agriculture natural ecosystems
• Levels set by precipitation, run-off,
  evaporation, soil drainage
• Higher temp increases evaporation, removing
  moisture
• Models differ due to different temp
  precipitation predictions

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Future Ecosystem Changes

• Vegetation response to CO2 concentrations double
  present levels

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Multiple stresses

• Climate only one of changes in global environment
• Effects of climate other environmental changes

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Common Climate Changes
Midwest

• Predict increased warming, precipitation,
  evaporation

Pacific northwest
Islands
Northwest
West
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Common Issues

• Weather extreme increase
• Natural ecosystem, species, and biodiversity
  changes
• Water resource changes (lake levels, snow
  melting)
• Public health and
  safety
• Shifts in tourism and
  recreation
• Sea-level variability

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Southeast

• Half of remaining wetlands located here
• Rapid growth (30 population increase b/w 1970
  1990)
• Produces half of U.S. timber supplies

• Warming and thus higher evaporation predicted
• Lower soil moisture
• Significant precipitation increase also predicted

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Southeast Future Climate Scenarios
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Southeast Impacts on Humans

• Weather-related stresses
• frequent weather disasters drought, hurricane
• flooding in Texas (low-lying coast counties)
• high heat index poor air-quality to increase
  death rate
• southern heat wave drought of 1998 6 billion
  in damages over 200 deaths
• 8 to 15 heat index
  increase for
  southernmost states

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Southeast Climate Effects

• Crop and economy impact
• will vary according to area and crop
• adaptation switch crops, vary planting dates,
  water usage, crop rotations, fertilizers
• Water quality stresses
• sewage, dead animals, fuel, chemicals from
  flooding
• high temp- decrease dissolved oxygen

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Southeast Climate effects

• Coastal area threats
• sea-level rise will impact ecosystems
• Obvious impacts on coastal flooding
• Forest productivity shifts
• greater CO2 production increase in north
• Pine trees

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Climate Change Summary

• Warmer temp will lead to more vigorous
  hydrological cycle- severe droughts /or floods
• Uncertain predictions, especially in timing,
  magnitude, regional patterns of climate change
• Balance of evidence shows there is discernible
  human influence on global climate

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