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Search for Life in the Universe. Chapter 10 Short-Term Global Warming. Outline. Recent Warming Correlation with CO 2 Models and Uncertainties Consequences Intergovernmental Panel on Climate Change (IPCC). Recent Warming. Global warming: average of the planet Current measurements:
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Search for Life in the Universe Chapter 10 Short-Term Global Warming AST 248, Spring 2007
Outline • Recent Warming • Correlation with CO2 • Models and Uncertainties • Consequences • Intergovernmental Panel on Climate Change (IPCC) AST 248, Spring 2007
Recent Warming • Global warming: average of the planet • Current measurements: • Satellites • Weather stations • Ships: ocean temperatures • Past measurements: • Urban heat islands • Missing ocean temperatures • Warming: • 0.8oC in the last century • 0.6oC in the last 30 years • Stronger in northern hemisphere (more land) AST 248, Spring 2007
Correlation with CO2 • CO2 measurements: • Since 1958: directly measured in the atmosphere • Past: tree rings and Antarctic ice sheet • Isotopic abundances measure past temperatures: • Antarctic ice sheet • Sediments on ocean floor • Correlation of temperature with CO2 • Strong correlation • Amplitude ~10oC >> changes observed now • Oscillation timescale ~100,000 yr • Current slope very steep AST 248, Spring 2007
Models and Uncertainties • ~105 yr: direct empirical data • < 104 yr: complex feedback mechanisms • Modeling shows good agreement with observations • But how much of the models is data fitting • What is the predictive power? AST 248, Spring 2007
Conseqauences • Temperature rise by 3-5oC by 2100 • Shift in regions of food production • Polar regions warm most • Northern hemisphere warms more • More moisture → stronger storms • Rise ins sea level by up to ~1 m • Ecological changes AST 248, Spring 2007
Intergovernmental Panel on Climate Change (IPCC) • 2001 reports: • Carbon dioxide capture and storage • Ozone layer • Working groups and synthesis report • 2007 working groups and synthesis report: • WG1: Physical science basis (02/02/2007) • WG2: Climate change impacts, adaptation and vulnerability (04/06/2007) • WG3: Mitigation of climate change (05/04/2007) • Synthesis report (11/12-16/2007) AST 248, Spring 2007