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Climate and Global Change

Warm near the equator and cold at the poles, our planet is able to support a variety of living things because of its diverse regional climates. The average of all these regions makes up Earth's global climate. Climate has cooled and warmed throughout Earth history for various reasons. Rapid warming like we see today is unusual in the history of our planet. The scientific consensus is that climate is warming as a result of the addition of heat-trapping greenhouse gases which are increasing dramatically in the atmosphere as a result of human activities.

Earth's global average surface <a
  href="/php/tour_test_sqli.php?page=/earth/climate/ipcc_feb2007.html&edu=elem">warming</a> relative to the
  1980-1999 average over the past 100 years is shown in the black line.
  Predictions of the amount of warming in the future are shown by the red,
  green, and purple lines. These predictions, developed with <a
  href="/php/tour_test_sqli.php?page=/earth/climate/cli_models.html&edu=elem">computer models</a>, make different
  assumptions about how many <a
  href="/php/tour_test_sqli.php?page=/earth/climate/cli_greengas.html&edu=elem">greenhouse gases</a> we release into the
  atmosphere in the future.<p><small><em> A Windows to the Universe image based on a graph from the IPCC 4th Assessment Report</em></small></p><a href="/php/tour_test_sqli.php?page=/earth/polar/cryosphere_permafrost1.html&edu=elem">Permafrost</a> is
ground that is below the freezing point of water (0°C or 32°F) for two
or more years. Permafrost is found at high latitudes like the
<a href="/php/tour_test_sqli.php?page=/earth/polar/polar_north.html&edu=elem">Arctic</a> and
<a href="/php/tour_test_sqli.php?page=/earth/polar/polar_south.html&edu=elem">Antarctic</a>.
It is also common at high altitudes - like mountainous areas wherever the
<a href="/php/tour_test_sqli.php?page=/earth/climate/cli_define.html&edu=elem">climate</a> is
cold. 
Permafrost has been thawing relatively quickly in recent years. Scientists
have found that the rate of permafrost thaw has increased because of <a href="/php/tour_test_sqli.php?page=/earth/climate/cli_effects.html&edu=elem">global
warming</a>.<p><small><em>Image courtesy of the    USGS</em></small></p>Coral animals build reefs in warm, tropical seawater. However, <a href="/php/tour_test_sqli.php?page=/earth/changing_planet/ocean_temperatures_intro.html&edu=elem">seawater can be too warm</a> for their liking.  If waters get too warm, coral animals lose the algae that live within their little bodies, a process called coral bleaching. Without the algae, corals have less nutrition. Unless cooler temperatures return, allowing algae to
 return, the coral dies.<p><small><em>Credit: UNC</em></small></p>Many forms of air pollution are human-made. Industrial plants, power plants
and vehicles with internal combustion engines produce <a href="/php/tour_test_sqli.php?page=/earth/climate/nitrogen_airpollution.html&edu=elem">nitrogen
oxides</a>,
<a href="/php/tour_test_sqli.php?page=/earth/Atmosphere/vocs.html&edu=elem">VOCs</a>,
<a href="/php/tour_test_sqli.php?page=/physical_science/chemistry/carbon_monoxide.html&edu=elem">carbon monoxide</a>,
<a href="/php/tour_test_sqli.php?page=/physical_science/chemistry/carbon_dioxide.html&edu=elem">carbon dioxide</a>,
<a href="/php/tour_test_sqli.php?page=/physical_science/chemistry/sulfur_oxides.html&edu=elem">sulfur dioxide</a> and
<a href="/php/tour_test_sqli.php?page=/earth/Atmosphere/particulates.html&edu=elem">particulates</a>.
Some of these gases are <a href="/php/tour_test_sqli.php?page=/earth/climate/cli_greengas.html&edu=elem">greenhouse
gases</a>,
meaning that they retain heat in the Earth's atmosphere, due to the Earth's
<a href="/php/tour_test_sqli.php?page=/earth/climate/earth_greenhouse.html&edu=elem">greenhouse effect</a>.<p><small><em>Image copyright UCAR</em></small></p><b><i>Looking for online resources to use in support of climate change education?</i></b>  Our <a href="/php/tour_test_sqli.php?page=/teacher_resources/climate.html&edu=elem">Climate Change Educator Resources page</a> provides links to online content, classroom activities, interactives, and videos as well as resources provided by other leading organizations and agencies on this topic.  Our <a href="/php/tour_test_sqli.php?page=/teacher_resources/climate_change_course.html&edu=elem">Climate Change Course Content page</a> provides links to online content for a range of climate change associated topics.<p><small><em>Image courtesy of   Mila Zinkova, Creative Commons Attribution ShareAlike license</em></small></p>How did life evolve on <a href="/php/tour_test_sqli.php?page=/earth/earth.html&edu=elem">Earth</a> during the <a href="/php/tour_test_sqli.php?page=/earth/past/Archean.html&edu=elem">Archean</a>, when the <a href="/php/tour_test_sqli.php?page=/sun/sun.html&edu=elem">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/php/tour_test_sqli.php?page=/earth/polar/cryosphere_glacier1.html&edu=elem">glaciated</a>, if <a href="/php/tour_test_sqli.php?page=/earth/climate/earth_greenhouse.html&edu=elem">greenhouse</a> gas concentration was the same as today.  <a href="http://www.manchester.ac.uk/aboutus/news/display/?id=10798">Researchers</a> studying the <a href="/php/tour_test_sqli.php?page=/physical_science/physics/atom_particle/isotope.html&edu=elem">isotopic</a> signatures of Earth's early atmosphere in <a href="/php/tour_test_sqli.php?page=/earth/geology/rocks_intro.html&edu=elem">rocks</a> from Northern Australia have ruled out high levels of <a href="/php/tour_test_sqli.php?page=/physical_science/chemistry/nitrogen_molecular.html&edu=elem">nitrogen</a> as a possible way to increase warming from <a href="/php/tour_test_sqli.php?page=/earth/Atmosphere/overview.html&edu=elem">atmospheric</a> <a href="/php/tour_test_sqli.php?page=/physical_science/chemistry/carbon_dioxide.html&edu=elem">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p>

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF