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.

<a href="/earth/polar/cryosphere_permafrost1.html&edu=high&dev=1">Permafrost</a> is
ground that is below the freezing point of water (0C or 32F) for two
or more years. Permafrost is found at high latitudes like the
<a href="/earth/polar/polar_north.html&edu=high&dev=1">Arctic</a> and
<a href="/earth/polar/polar_south.html&edu=high&dev=1">Antarctic</a>.
It is also common at high altitudes - like mountainous areas wherever the
<a href="/earth/climate/cli_define.html&edu=high&dev=1">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="/earth/climate/cli_effects.html&edu=high&dev=1">global
warming</a>.<p><small><em>Image courtesy of the    USGS</em></small></p>Many forms of air pollution are human-made. Industrial plants, power plants
and vehicles with internal combustion engines produce <a href="/earth/climate/nitrogen_airpollution.html&edu=high&dev=1">nitrogen
oxides</a>,
<a href="/earth/Atmosphere/vocs.html&edu=high&dev=1">VOCs</a>,
<a href="/physical_science/chemistry/carbon_monoxide.html&edu=high&dev=1">carbon monoxide</a>,
<a href="/physical_science/chemistry/carbon_dioxide.html&edu=high&dev=1">carbon dioxide</a>,
<a href="/physical_science/chemistry/sulfur_oxides.html&edu=high&dev=1">sulfur dioxide</a> and
<a href="/earth/Atmosphere/particulates.html&edu=high&dev=1">particulates</a>.
Some of these gases are <a href="/earth/climate/cli_greengas.html&edu=high&dev=1">greenhouse
gases</a>,
meaning that they retain heat in the Earth's atmosphere, due to the Earth's
<a href="/earth/climate/earth_greenhouse.html&edu=high&dev=1">greenhouse effect</a>.<p><small><em>Image copyright UCAR</em></small></p>Scientists are concerned that melting Arctic sea ice will increase the amount of fresh water in the <a href="/earth/polar/arctic_currents.html&edu=high&dev=1">Beaufort Gyre</a>, which could spill out into the Atlantic and cause major climate shifts in North America and Western Europe. Watch the <a href="/earth/changing_planet/freshwater_arctic.html&edu=high&dev=1">Changing Planet: Fresh Water in the Arctic video</a>.<p><small><em> Courtesy of Jack Cook, WHOI (<a href="http://www.whoi.edu">Woods Hole Oceanographic Institute</a>)</em></small></p>On November 7, 2013, Typhoon Haiyan (Yolanda in the Philippines) made landfall, with imated wind speeds of ~315 km/hr - the strongest <a href="/earth/Atmosphere/hurricane/intensity.html&edu=high&dev=1">tropical cyclone</a> to make landfall in recorded history.  As Haiyan moved across the Philippines before reaching Vietnam and China, its <a href="/earth/Atmosphere/wind.html&edu=high&dev=1">winds</a> and <a href="/earth/Atmosphere/hurricane/surge.html&edu=high&dev=1">storm surge</a> left devastation in its wake, leading to massive loss of life, destruction of homes, and hundreds of thousands of displaced inhabitants. <a href="http://www.cnn.com/2013/11/09/world/iyw-how-to-help-typhoon-haiyan/index.html">How to Help</a><p><small><em>Image courtesy of COMS-1, SSEC, University of Wisconsin-Madison</em></small></p>Greenland's <a href="http://www.windows2universe.org/earth/polar/cryosphere_glacier1.html">ice sheet</a> saw a record <a href="http://www.windows2universe.org/headline_universe/olpa/greenland_10dec07.html">melt</a> in July 2012.  Scientists studying this event have found that this melting event was triggered by an influx of unusually warm air and amplified by the presence of a blanket of thin low-level <a href="http://www.windows2universe.org/earth/Atmosphere/cloud.html">clouds</a> which pushed temperatures up above freezing.  For more information see the <a href="http://www.news.wisc.edu/21638">press release</a> from the University of Wisconsin Madison.<p><small><em>Image courtesy of University of Wisconsin-Madison</em></small></p><b><i>Looking for online resources to use in support of climate change education?</i></b>  Our <a href="/teacher_resources/climate.html&edu=high&dev=1">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="/teacher_resources/climate_change_course.html&edu=high&dev=1">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>

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