We have heard a lot from environmentalists about the melting icecaps and the glaciers in Alaska, Canada and elsewhere.  They talk about this causing rising sea levels that will flood many coastal areas, causing the extinction of Polar Bears and other animals that live on the ice, and the possibility of ocean currents being changed resulting in much colder temperatures for Europe.  
    One thing I haven't heard any talk about is diseases.  In the past few decades, destruction of rain forest has released a number of deadly diseases caused by bacteria that were trapped inside trees that were cut down or viruses that lived in animals in a very small area that spread to humans when man invaded their territory.  Could something similar happen from the melting ice?  Is is possible that some virus or bacteria that is no longer active in the world may be trapped in ice that froze thousands of years ago?  And will releasing those germs when the ice melts expose us to ancient plagues that we no longer have any resistance to?  Something to consider before you say "so what if the ice melts and floods Miami, we will just make new beaches on the new shoreline".  It might not be that simple.