Global Atmospheric Changes

The Atmosphere and Climate

• Solar Radiation and Climate– Insolation = sunshine

• Major determinant of climate– Makes life on Earth possible

• Liquid water• Warm planet• Photosynthesis

– Powers Earth’s biogeochemical cycles– Drives winds and ocean currents

Global Climate Change

• Earth’s average temperature is increasing– Based on daily measurements taken by:

• Meteorological stations, weather balloons, sea-surface buoys

– NOAA: global temperatures in1995 and 2001–2009 may have been highest in the last 1000 yrs

– Spring in Northern Hemisphere comes 6 days earlier than in 1959, Autumn comes 5 days later

– Increase in heat waves, heat-related deaths– Sea levels rising, glaciers retreating, more severe

hurricanes


• Scientific Consensus:– Human activities are largely responsible for current climate change

• IPCC: United Nations Intergovernmental Panel on Climate Change Predicts

– 1.8 to 4.0 °C (3.2-7.2 °F) increase in global temperature by 2100

– Higher maximum temperatures

– More hot days, fewer cold days

– Increase in heat index

– Changes in precipitation patterns

NASA Statement


• Causes:– Increase of atmospheric gases due to human

activities -- Greenhouse gases:• Carbon Dioxide (CO2)• Nitrous Oxide (N20)• Methane (CH4)• Chlorofluorocarbons (CFCs)• Ozone (O3)• Water (H2O) - steady amount-does not increase due to

human activity

Rise in Carbon Dioxide Concentration in the Atmosphere

More CO2 more heat in atmosphere– more transferred back to surface


• Aerosols tend to cool the atmosphere– Reflect sunlight into space

• Cooling effect much weaker than enhanced greenhouse effect

• Human and natural causes of aerosols– Sulfur emissions from fossil fuels– Volcanic eruptions


• Effects of Climate Change:– Sea-level rise

• Polar ice caps and continental glacier melts• Warm water expands in volume

– Changes in precipitation patterns• More droughts in some areas• More flooding in some areas• Fresh water availability


• Effects of Climate Change:• Impacts on agriculture

• Rising sea levels will flood deltas• Pests will become more prevalent• No irrigation water• Productivity may increase in some areas


• Effects of Climate Change:• Impacts on human health

• Heat-related illnesses• Disease-carrying mosquitoes will expand their range and

transmit more malaria, Dengue fever, yellow fever


• Effects of Climate Change:• Impact on biodiversity and ecosystems

• Warmer oceans lead to decline in populations of krillsilverfishAdelie penguins

• Warmer temperatures makes frogs more susceptible to fungal diseases

• Polar seas, coral reefs, coastal wetlands, tundra– Ocean acidification– Coral bleaching


• Mitigation– Develop alternatives to fossil fuels– Reduce energy use– Increase energy efficiency– Plant and maintain forests– Carbon Management

• Trap CO2 from smokestacks

• Sequester CO2 into geological formations or depleted oil/gas wells


• Adaptation– Move coastal settlements inland– Construct sea walls on coastal areas– Prevent saltwater intrusion– Find substitute crops to grow on warming land– Develop heat and drought resistant crops/trees– City planning

• Sewer systems• Storm runoff

Summary


Global Warming

Human Contribution

Global Atmospheric Changes

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