The climate has changed radically. From the beginning of the 20th century, fossil fuels were used for industries and development. The rapid growth in population and industrialization lead to more factories and pollution. Since the beginning of the Industrial revolution, we have added a lot of CO2 and other pollutants. The current rate of CO2 in air is 1.9ppmv/year. Present CO2 concentrations are higher than any time in at least the last 650,000 years. All this change has been brought about in nearly 100 years! This has lead to an average warming at a rate of about 0.29ºF per decade. This gradual increase in temperature can lead to great changes in the climate of the planet leading to heatwaves and record low temperatures. The eight warmest years in recent history have occurred from 2001. This clearly shows that the warming is taking place and something has to be done to stop it.

To know more about climate change visit:

http://www.epa.gov/climatechange/science/recenttc.html

Many climate changes have been observed.The earth surface and the atmosphere temperature increased.The snow cover and ice extent decreased.Sea level and ocean heat content increased also.