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/climate/cli_define.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Regional climate</a> is
the average weather pattern in a place over more than thirty years,
including the variations in
<a href="/earth/climate/cli_seasons.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">seasons</a>.
The climate of a region depends on many factors including sunlight,
altitude, topography, and proximity to oceans. Since the equatorial regions
receive more sunlight than the poles, climate varies with
<a href="/earth/climate/cli_latitude.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">latitude</a>.
This image shows how sea surface temperatures change at different latitudes.<p><small><em>Image courtesy of NOAA.  Public domain.</em></small></p>Scientists at the University of Michigan have found that <a href="/earth/polar/cryosphere_permafrost1.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">permafrost</a> in the <a href="/earth/polar/polar_north.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Arctic</a> is extremely sensitive to sunlight.  Exposure to sunlight releases carbon gases trapped in the permafrost, including <a href="/earth/climate/earth_greenhouse.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">climate-warming</a> <a href="/physical_science/chemistry/carbon_dioxide.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">carbon dioxide</a>, to the <a href="/earth/Atmosphere/overview.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">atmosphere</a> much faster than previously thought.<p><small><em>George Kling, The University of Michigan</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&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">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&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">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>As temperatures rise and soil moisture decreases, plants are stressed, which can lead to <a href="/earth/climate/crops_withering.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">crop withering</a>. <a href="/teacher_resources/online_courses/health/events_health.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Droughts</a> accompanied by increased temperatures can lead to famine, social and political disruptions. Scientists are  helping with early identification of drought that might trigger food shortages. Watch the NBC Learn video - <a href="/earth/changing_planet/withering_crops_intro.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Changing Planet: Withering Crops</a> to find out more.<p><small><em>Image taken by Tomas Castelazo, Creative Commons <a href=&quot;http://creativecommons.org/licenses/by/3.0/deed.en&quot;>Attribution 3.0 Unported</a> license.</em></small></p>How did life evolve on <a href="/earth/earth.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Earth</a> during the <a href="/earth/past/Archean.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Archean</a>, when the <a href="/sun/sun.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">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="/physical_science/physics/atom_particle/isotope.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</em></small></p><b><i>Looking for online resources about climate and climate change for your classroom?</i></b> Windows to the Universe is a free interlinked learning ecosystem to a wealth of resources on our site and elsewhere that support you on these topics, including <a href="/teacher_resources/climate_change_course.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">course readings</a>,  <a href="/php/teacher_resources/activity.php#6">classroom activities and presentations</a>, and online interactives.  Our <a href="/teacher_resources/climate.html&dev=1/earth/Atmosphere/moons/h/neptune/neptune_il.html">Climate Change Education Resources page</a> provides links to content you can use right away in the classroom!<p><small><em>   Ute Kaden/PolarTREC</em></small></p>

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