Introduction

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=90 BGCOLOR="#006699" TEXT="#080000" background="234d05a3.jpg"> <div> <FONT SIZE="5" COLOR="#000000" FACE="Arial" ><B>Arctic Climate Change</B></FONT><B>    </B><B> |     </B><A HREF="index.htm" TARGET="_top" TITLE="Arctic Climate Change"><U><B>home</B></U></A></div> <div> <B>Introduction</B>   |   <A HREF="id3.htm" TARGET="_top" TITLE="Task"><U>Task</U></A>   |   <A HREF="id19.htm" TARGET="_top" TITLE="Process"><U>Process</U></A>   |   <A HREF="id4.htm" TARGET="_top" TITLE="Information Resources"><U>Information Resources</U></A>   |   <A HREF="id15.htm" TARGET="_top" TITLE="Guidance"><U>Guidance</U></A>   |   <A HREF="id16.htm" TARGET="_top" TITLE="Conclusion"><U>Conclusion</U></A>   |   <A HREF="id18.htm" TARGET="_top" TITLE="Evaluation"><U>Evaluation</U></A>   |   <A HREF="id20.htm" TARGET="_top" TITLE="Glossary"><U>Glossary</U></A>   |   <A HREF="id17.htm" TARGET="_top" TITLE="For Teachers"><U>For Teachers</U></A>   |   <A HREF="id50.htm" TARGET="_top" TITLE="Webquest chronicle"><U>Webquest chronicle</U></A></div> <div> </div> </td> </tr><tr> <td valign="top" width=210 BGCOLOR="#FFCC66" TEXT="#080000" background="235d2123.jpg"> <div> <B><IMG SRC="247b4870.jpg" border=0 width="180" height="135" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <div> <B><IMG SRC="246b49f0.jpg" border=0 width="180" height="159" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <div> <B><IMG SRC="2e0b4890.jpg" border=0 width="180" height="137" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> </td> <td valign="top" height=390 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <I>Introduction</I></div> <bR> <div> The phenomenon of global warming refers to the increase, over the past century or so, of the ground-level (or ocean-level) atmospheric temperature averaged over the whole earth.  For example, the graph below clearly shows that globally-averaged temperatures have risen about 1<FONT SIZE="3" COLOR="#000000" FACE="Arial" >o</FONT>C (1.8<FONT SIZE="3" COLOR="#000000" FACE="Arial" >o</FONT>F) over the past 144 years.</div> <DIV ALIGN="LEFT"></DIV> <div> <IMG SRC="23818640.gif" border=0 width="792" height="612" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <div> Global temperatures since 1861, as measured by ground-level weather stations.  (Source: UK Meteorological Office, www.met-office.gov.uk/research/hadleycentre/obsdata/globaltemperature.html)</div> <bR> <div> There are also a number of important issues that the graph above doesn't address.  For example, why did the globally-averaged temperatures rise rapidly during the 1920s and 1930s and the 1980s and 1990s, but not during the other decades?  Why did global temperatures actually decrease during the 1950s and 1960s?   </div> <bR> <div> The more you look at the graph above, the more you begin to realize that it actually raises even more questions about global warming.  The earth's surface is covered by water (70%) and land (30%), two very different materials.  Has the portion of the earth covered by land heated up more than the portion covered by water?  What about different regions of the globe: has the northern hemisphere warmed at the same rate as the southern hemisphere?  And what about altitude?  The atmosphere is several hundred miles thick.  Has the ground-level air warmed at the same rate as the air at higher altitudes?</div> <bR> <div> This webquest focuses on climate changes that are occurring in the Arctic.  The Arctic is a highly sensitive environmental region.  Climate changes in the Arctic are likely to affect people, plants, animals and the environment more strongly than in other parts of the world.</div> <bR> <div> Using a high-quality collection of historical temperature measurements assembled by atmospheric scientists at the University of Wisconsin-Milwaukee, you will investigate several questions related to Arctic climate change.  To begin the quest, explore the links below to gain the background information necessary to understand and complete your tasks.</div> <bR> <bR> <div> <TABLE BORDER="0" CELLPADDING="2" CELLSPACING="3" WIDTH="718" BORDERCOLORLIGHT="#C0C0C0" BORDERCOLORDARK="#808080" FRAME="BOX" RULES="ALL" HSPACE="0" VSPACE="0" > <tR> <tD VALIGN=CENTER HEIGHT= 147 WIDTH="171"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="147" ALIGN="bottom" WIDTH="171" HSPACE="0" VSPACE="0"></tD> <tD VALIGN=CENTER><NOBR><div> <IMG SRC="23b968d0.gif" border=0 width="150" height="141" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> </NOBR></tD> <tD VALIGN=CENTER><NOBR><div> <IMG SRC="23f96780.jpg" border=0 width="150" height="120" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> </NOBR></tD> <tD VALIGN=CENTER><NOBR><div>   <FONT SIZE="3" COLOR="#000000" FACE="Arial" ><IMG SRC="23d967a0.gif" border=0 width="150" height="122" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></FONT></div> </NOBR></tD> </tR> <tR> <tD VALIGN=TOP HEIGHT= 139 WIDTH="171"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="139" ALIGN="bottom" WIDTH="171" HSPACE="0" VSPACE="0"></tD> <tD VALIGN=TOP WIDTH="171"><div> <A HREF="id29.htm" TARGET="_top" TITLE="Global Warming and the Atmospheric Green"><U>Global warming and the atmospheric greenhouse effect</U></A></div> </tD> <tD VALIGN=TOP WIDTH="171"><div> <A HREF="id30.htm" TARGET="_top" TITLE="Temperature Measurements from Earth"><U>Temperature measurements from earth</U></A></div> </tD> <tD VALIGN=TOP WIDTH="174"><div> <A HREF="id55.htm" TARGET="_top" TITLE="Temperature Measurements from Space"><U>Temperature measurements from space</U></A></div> </tD> </tR> </TABLE></div> <div>    </div> <DIV ALIGN="LEFT"></DIV> <div> <IMG SRC="2e593670.jpg" border=0 width="147" height="103" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"><IMG SRC="2e685670.jpg" border=0 width="133" height="103" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"><IMG SRC="2e792670.jpg" border=0 width="146" height="103" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"><IMG SRC="2e844670.jpg" border=0 width="68" height="103" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> </td> </tr></table></body>