my assignment3

This is my assignment 3,its about Global warming. Global Warming is real and underway. The mainstream scientific consensus on global warming is becoming clearer every day; change in our climate are real and they are underway .Since the beginning of the 20th century, the mean surface temperature of the earth has increased by about 1.1f．Over the last 40 years, the temperature was increased by about 0.5F.Warming in 20th century was greater than at any time during the past 400-600 years. Seven of ten warmest years in the 20th century occurred in the 1990s due to one of the strongest El Ninos.

1998 was the hottest year since reliable temperature measurements began. In addition, changes in the natural environment support the fact that the earth is warming up; Mountain glaciers are receding; The ice in the Arctic has lost about 40% of its thickness over the past four decades; The global sea level has risen about three times faster over the past 100 years compared to the previous 3,000 years; There are a growing number of studies that show plants and animals changing their range and behavior in response to shift in climate.