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We now offer the Cool It! card game in our Science Store. Cool It! is the new card game from UCS that teaches kids about the choices we have when it comes to climate change.

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="/earth/climate/ipcc_feb2007.html&edu=high&dev=1">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="/earth/climate/cli_models.html&edu=high&dev=1">computer models</a>, make different
  assumptions about how many <a
  href="/earth/climate/cli_greengas.html&edu=high&dev=1">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>Roaming across Arctic <a
  href="/earth/polar/sea_ice.html&edu=high&dev=1">sea ice</a>, <a
  href="/earth/polar/polar_bears_jan07.html&edu=high&dev=1">polar
  bears</a> peer through cracks in the ice to look for ringed seals, their
  favorite food, in the water below. Almost all of a polar bear's food comes
  from the sea. The <a
  href="/earth/polar/sea_ice.html&edu=high&dev=1">floating sea
  ice</a> is a perfect vantage point for the bears as they hunt for food.
  Unfortunately, the amount of sea ice floating in the <a
  href="/earth/polar/polar_north.html&edu=high&dev=1">Arctic
  region</a> is shrinking each year, and getting farther apart.<p><small><em>Image courtesy of Ansgar Walk.  Creative Commons Attribution-Share Alike 2.5 Generic license.</em></small></p>Although we humans have never experienced fast <a href="/earth/climate/climate.html&edu=high&dev=1">global
warming</a>, our
planet has. And our planet keeps records of what happened. The oldest
records that the
<a href="/earth/earth.html&edu=high&dev=1">Earth</a> keeps
are in its
<a href="/earth/geology/sed_intro.html&edu=high&dev=1">rocks</a>.
In this image, <a href="/headline_universe/olpa/methane_28may08.html&edu=high&dev=1">geologists Chris von der Borch and Dave
Mrofka</a> collect
sediment samples in South Australia. These rocks hold clues to help
explain why climate changed abruptly 635 million years ago.<p><small><em>                    Courtesy of Martin Kennedy, UCR</em></small></p>Coral animals build reefs in warm, tropical seawater. However, <a href="/earth/changing_planet/ocean_temperatures_intro.html&edu=high&dev=1">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>How did life evolve on <a href="/earth/earth.html&edu=high&dev=1">Earth</a> during the <a href="/earth/past/Archean.html&edu=high&dev=1">Archean</a>, when the <a href="/sun/sun.html&edu=high&dev=1">Sun</a> was about 25% weaker than today?  The Earth should have been <a href="/earth/polar/cryosphere_glacier1.html&edu=high&dev=1">glaciated</a>, if <a href="/earth/climate/earth_greenhouse.html&edu=high&dev=1">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&edu=high&dev=1">isotopic</a> signatures of Earth's early atmosphere in <a href="/earth/geology/rocks_intro.html&edu=high&dev=1">rocks</a> from Northern Australia have ruled out high levels of <a href="/physical_science/chemistry/nitrogen_molecular.html&edu=high&dev=1">nitrogen</a> as a possible way to increase warming from <a href="/earth/Atmosphere/overview.html&edu=high&dev=1">atmospheric</a> <a href="/physical_science/chemistry/carbon_dioxide.html&edu=high&dev=1">carbon dioxide</a>.<p><small><em>Image courtesy of Manchester University</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>

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA