As permafrost thaws, the land, atmosphere, water resources, ecosystems, and human communities are affected. Coastal areas and hillsides are vulnerable to erosion by thawing of permafrost.  Thawing permafrost also causes a positive feedback to global warming, as carbon trapped within the once-frozen soils is released as <a href="/physical_science/chemistry/methane.html&dev=1/heat_present_10feb09.ppsx">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&dev=1/heat_present_10feb09.ppsx">greenhouse gas</a>.
Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&dev=1/heat_present_10feb09.ppsx">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the    USGS</em></small></p>New observations by the MESSENGER spacecraft provide  support for the hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed (shown in red) polar craters. Areas where polar deposits of ice imaged by Earth-based radar are shown in yellow.<p><small><em>Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory</em></small></p><p>You don't normally see <a href="/space_weather/space_weather.html&dev=1/heat_present_10feb09.ppsx">space weather</a> forecasted on the evening news, but it does impact life on <a href="/earth/earth.html&dev=1/heat_present_10feb09.ppsx">Earth</a> in many ways. What are the threats posed from all of these natural disasters and how can we work to mitigate those threats beforehand? </p>
<p>Check out the materials about natural disasters in <a href="/earth/natural_hazards/when_nature_strikes.html&dev=1/heat_present_10feb09.ppsx">NBC Learn Videos</a>, and their earth system science connections built up by the related secondary classroom activities.</p><p><small><em>NBC Learn</em></small></p>This dramatic view of Jupiter's <a href="/jupiter/atmosphere/J_clouds_GRS.html&dev=1/heat_present_10feb09.ppsx">Great Red Spot</a> and its surroundings was obtained by <a href="/space_missions/voyager.html&dev=1/heat_present_10feb09.ppsx">Voyager 1</a> on Feb. 25, 1979, when the spacecraft was 5.7 million miles (9.2 million kilometers) from Jupiter. Cloud details as small as 100 miles (160 kilometers) across can be seen here. The colorful, wavy cloud pattern to the left of the Red Spot is a region of extraordinarily complex end variable wave motion.<p><small><em>Image courtesy of NASA</em></small></p><p>The United Nations <a href="http://reliefweb.int/sites/reliefweb.int/files/resources/PAND_report.pdf" target="_blank">estimated</a> that between 1994-2015, there were 6,873 natural disasters worldwide, which affected 218 million people and claimed 1.35 million lives. </p>
<p>Check out the materials about natural disasters in <a href="/earth/natural_hazards/when_nature_strikes.html&dev=1/heat_present_10feb09.ppsx">NBC Learn Videos</a>, and their earth system science connections built up by the related secondary classroom activities.</p><p><small><em>NBC Learn</em></small></p>A near-Earth <a href="/our_solar_system/asteroids.html&dev=1/heat_present_10feb09.ppsx">asteroid</a> - named 2012 DA14 by astronomers - passed within 17,200 miles from Earth on February 15, 2013. On closest approach at about 1:25 p.m. CST on February 15, although it was within the orbit of the <a href="/earth/moons_and_rings.html&dev=1/heat_present_10feb09.ppsx">Moon</a> and even geosynchronous <a href="/space_missions/satellites.html&dev=1/heat_present_10feb09.ppsx">satellites</a>, it didn't strike Earth!  Find out more from <a href="http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130201315144.html">NASA</a>! Fragments of a meteorite hit Chelyabinsk, Russia on 2/15/2013 <a href="http://www.reuters.com/article/2013/02/15/us-russia-meteorite-idUSBRE91E05Z20130215">injuring over 500</a>. Learn about <a href="http://www.windows2universe.org/our_solar_system/meteors/meteors.html">meteors and meteorites</a>.<p><small><em>NASA/JPL-CalTech</em></small></p>

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