The massive 9.0 magnitude <a href="/earth/geology/quake_1.html&dev=">earthquake</a> off of Honshu, Japan on <a href="/headline_universe/march112011earthquaketsunami.html&dev=">11 March 2011</a> generated a <a href="/earth/tsunami1.html&dev=">tsunami</a> that exceeded 10 meters on the coast near the epicenter.  This image shows model projections for the tsunami wave height in cm which are in good agreement with the observed waves. Our thoughts and prayers are with those who were lost, and their families, as we remember this event.<p><small><em><a href="http://blogs.agu.org/wildwildscience/files/2011/03/680_20110311-TsunamiWaveHeight.jpg">NOAA Tsunami Wave Height Projections image</a></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=">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=">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 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=">methane</a>, a powerful <a href="/earth/climate/cli_greengas.html&dev=">greenhouse gas</a>.
Watch the NBC Learn video - <a href="/earth/changing_planet/permafrost_methane_intro.html&dev=">Thawing Permafrost and Methane</a> to find out more.<p><small><em>Image courtesy of the    USGS</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=">crop withering</a>. <a href="/teacher_resources/online_courses/health/events_health.html&dev=">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=">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>This historic image is the first ever taken from a spacecraft in orbit about <a href="/mercury/mercury.html&dev=">Mercury</a>, the innermost planet of the solar system.  Taken on 3/29/2011 by <a href="/space_missions/robotic/messenger/messenger.html&dev=">MESSENGER</a>, it shows numerous craters across the <a href="/mercury/Interior_Surface/Surface/surface_overview.html&dev=">surface</a> of the planet.  Temperatures there can reach over 800F because Mercury is so close to the Sun and rotates so slowly.  MESSENGER entered orbit around Mercury earlier in March 2011.<p><small><em>NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington</em></small></p>Sinkholes are <a href="/teacher_resources/main/frameworks/esl_bi8.html&dev=">natural hazards</a> in many places around the world. They are formed when water dissolves underlying <a href="/earth/Water/carbonates.html&dev=">limestone</a>, leading to collapse of the surface.  Hydrologic conditions such as a lack of rainfall, lowered water levels, or excessive rainfall can all contribute to sinkhole development. On 2/28/2013, a sinkhole suddenly developed under the house outside of Tampa, Florida, leading to the tragic death of its occupant, Jeff Bush.<p><small><em>Image courtesy of Southwest Florida Water Management District</em></small></p>

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