Global warming is becoming a serious concern for all inhabitants of the planet Earth. Gradually over the years, our climate has been warming up. For those of us who live in the Northern Hemisphere, our first reaction might be "That's okay with me. Our summers are too short anyway". However, even a minor change in the Earth's temperature of only a few degrees will result in dramatic changes to our climate.
During the last Ice Age when most of the Northern Hemisphere was covered in glaciers, the average temperature of our planet was only 2 to 3 degrees Celius colder than what it is today. Doesn't sound like much, but the result was that much of Canada was covered in ice up to a few kilometers in depth.
So imagine what could happen if our average temperature was to rise by a couple of degrees Celius!