According to the latest draft of the U.S National Climate Change Assessment report, the main reason for climate change in the past 50 years has been human activities, and more specifically the burning of fossil fuels.
Changes in local climate result in more frequent severe weather events. In addition, they affect infrastructure, water supply, agricultural production and public health. The damages caused by hurricanes, heat waves, droughts and floods add up to billions of dollars.
The draft report is publicly available, but before the final version is compiled, the National Academies of Sciences should conduct a final evaluation and review.
According to the report, the average temperatures in the U.S, have increased by about 1.5 degrees F (0.83 degree C) since 1895. The high concentrations of greenhouse gases already present in the atmosphere might result in further increase by 2 to 4 degrees F (1.1 to 2.2 degrees C) in the next few decades.
Although the report indicates some positive consequences such as longer growing season, the reduced water supply, vulnerable infrastructure, increased extreme weather events, air pollution, as well as ocean acidification, pose a serious threat to human health.
The U.S. Department of Commerce established an advisory committee, which is responsible for integrating federal research, similar to earlier assessments from years 2000 and 2009, on environmental change and its implications for society. The committee consists of thirteen department and agencies, which include NASA, the Agricultural Department, various academic institutions, businesses, and nonprofit organizations among others.
According to Senator Barbara Boxer, head of the Senate environment committee, the draft warns everyone and urges immediate actions towards reducing of carbon pollution.