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Climate Change Impacts in the Gulf Coast

Climate Change Impacts in the Gulf Coast. Philip B. Bedient Civil & Environmental Engineering Rice University. Earth’s climate has always been changing Ice age (2 m.y.a.), glacial periods, polar ice caps 18,000 yrs ago: cold spell & continental glaciers.

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Climate Change Impacts in the Gulf Coast

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  1. Climate Change Impacts in the Gulf Coast Philip B. Bedient Civil & Environmental Engineering Rice University

  2. Earth’s 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 0.6°C In past 10,000 yrs, global temp. has never varied more than 1.5°C Climate Change History

  3. 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

  4. Key Predictions for Future • Increased warming • 5-9°F 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

  5. Greenhouse effect • Delicate balance of incoming & outgoing energy in earth-atmosphere • Atmosphere gases (water vapor, CO2, CH4, halocarbons, O3) absorb Earth’s 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 can’t pass into space

  6. Increasing Greenhouse Gases • Unusual rapid warming of 0.6°C 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

  7. Climate Assessment Tools • Historical records & climate simulations • General Circulation Model (GCM) • model Earth’s climate • incomplete, but still state-of-science • Two main models- Hadley & Canadian

  8. 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

  9. Past & Future Temperature Change

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

  11. 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

  12. Future Ecosystem Changes • Vegetation response to CO2 concentrations double present levels

  13. Multiple stresses • Climate only one of changes in global environment • Effects of climate & other environmental changes

  14. Common Climate Changes Midwest • Predict increased warming, precipitation, evaporation Pacific northwest Islands Northwest West

  15. 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

  16. 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 Southeast

  17. Southeast: Future Climate Scenarios

  18. 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

  19. 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

  20. 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

  21. 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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