Global Warming

Most scientists agree the global average temperature has risen over the last century. Many of them attribute this to the use of fossil fuels to generate electricity and power cars by man. On the other hand there are some scientists who believe the change in temperature is caused by natural climatic variations on the earth. What do you think? Is man responsible for the rising temperatures or are they part of a natural cycle that will shortly be replaced by a period of cooling? If we are to blame, should we scrap our cars, and reduce our consumption of electricity, or does the responsibility lie with government to do something about the problem?