Observed Global Climate Change
Review of last lecture Air pollution. 2 categories 6 types of major pollutants: particulates, carbon oxides, sulfur dioxides, nitrogen oxides, volatile organic compounds, ozone Dispersion of air pollution. Dependence on wind speed, stability (name of 3 types) and inversion (name of 2 types) Air quality index History of air pollution: The Medieval pollution, The 16 th - 19 th centuries, The 20 th century, The 21 st century
How do human activities change the global climate? Human beings are changing the global climate system in three different ways: Change land cover (deforestation and urbanization) Release or cleanse pollutants (aerosols) Release or cleanse greenhouse gases
The Intergovernmental Panel on Climate Change (IPCC) is organized by the World Meteorological Organization, and endorsed by the United Nations General Assembly. This is a worldwide enterprise that includes literally thousands of scientists that are involved in producing and critiquing a definitive statement on climate change. The political controversies have centered around condensed summaries produced for policy makers. We have had 5 assessments by IPCC so far. First Assessment Report (1990) Second Assessment Report (1995) Third Assessment Report (2001) Fourth Assessment Report (2007): Nobel Peace Prize Fifth Assessment Report ( ) How is scientific consensus achieved on global warming?
The most common atmospheric circulation structure L H H L Heating Cooling or No Heating Imbalance of heating Imbalance of temperature Imbalance of pressure Wind Radiation Convection Conduction Latent/Sensible Biosphere Land/Ocean/Ice/Stra tosphere Feedback Greenhouse Gases Pollution Clouds Precipitation (Latent heat) Spiritual Social Health Economy
Observed change of greenhouse gases Global atmospheric concentrations of CO 2 and CH 4 have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice core measurements spanning the last 650,000 years!
Radiative heating of greenhouse gases
Source of greenhouse gases CO 2 fossil fuel use is the dominant cause of CO 2 increase
GHG Emissions by Sector
Greenhouse gas emissions per capita The developed countries and developing countries contribute almost equally to the emissions of GHGs.
Video: Climate Change 2013 Working Group I: The Physical Science Basis
Observed Change in Global Temperature: Significant warming
Global map of temperature change: Largest warming in Arctic (“Arctic amplification”) Larger warming over land than ocean
Global map of snow/ice cover
Observed Melting of Arctic Sea Ice ultiyear.ice.quikscat.mov
Melting of Greenland Ice Sheet – A huge contributor to sea level rise today Greenland is responsible for about 10% of the observed global sea level rise and accelerating. Greenland holds 7 m of sea level equivalent.
Observed Changes in Snow Cover: Significant melting
Melting of Mountain Glaciers: a major contributor to sea level rise IPCC (2001) Glacier retreat is a world-wide phenomena. Will affect water supply for millions: Kenya/Tanzania Northern India Andes Mountains
Qori Kalis Glacier, Peru Pedersen Glacier, Kenai Fjords National Park, Alaska Pasterze Glacier, Austria
Observed Changes in Global Sea Level
Observed Changes in Sea Level Largest in the western part of ocean basin
Summary: Observed significant changes
Change in Mean vs Change in Extremes
Observed changes in precipitation extremes: Increased contribution from very wet days
Summary: Observed significant changes in extreme weather
Summary Rapid increase of greenhouse gases (CO 2, CH 4, N 2 O) since 1750: far exceed pre-industrial values determined from ice core measurements spanning the last 650,000 years. Lead to strong radiative heating. Mainly caused by CO 2 fossil fuel use. The developed countries and developing countries contribute almost equally to the emissions of GHGs. Observed change of mean: air temperature, ocean temperature, melting of arctic sea ice, Greenland ice sheet, snow and glaciers, rising of sea level. Observed change of extreme events: extreme precipitation events, heat waves, strongest hurricanes
Works cited National Snow & Ice Data Center Biodiesel.htmlhttp:// Biodiesel.html sheet/greenland-ice-sheet-assessment-publishedhttp:// sheet/greenland-ice-sheet-assessment-published after-pictures-of-melting-glaciers.htmlhttp:// after-pictures-of-melting-glaciers.html york-city-photos-show-devastation/ york-city-photos-show-devastation/ ow_ice.htmlhttp:// ow_ice.html