FACT: The scientific consensus on the link between human activity
and climate change is as strong as the consensus on the link between cigarettes
Climate change refers to the long-term change in the distribution of weather patterns over periods of time that range from decades to millions of years. It may be a change in the average weather conditions or a change in the distribution of weather events with respect to an average, for example, greater or fewer extreme weather events. The climate change which we are currently experiencing is due to global warming. Global warming is caused by excessive greenhouse gasses (GHGs) in our atmosphere such as carbon dioxide (CO2), methane and nitrous oxide which prevent excess heat from escaping the near-surface of the earth.
In addition to an increase in the average temperature of the earth and the seas, we can expect - an indeed are already experiencing - changes in the climate that include:
We can expect more frequent heavy downpours and snowfalls, since warmer air can hold more water vapor. Already, the number of heavy precipitation events in the United States increased 24 percent between 1948 and 2006, helping to make flooding the most common weather-related disaster in the U.S. Recent years have seen a string of incredibly destructive floods and snowstorms, including the 2008 Midwest flood that caused $8 to $10 billion in damage and 2010's "Snowmaggedon" that cost the East Coast more than $2 billion.
We are already seeing fewer-but more intense-hurricanes worldwide, and that the number of intense Category 4 and 5 hurricanes in the Atlantic may nearly double over the course of the next century. Estimated damages from the seven most costly hurricanes to strike the U.S. since 2005 exceed $200 billion.
Heat waves are projected to be more frequent, more intense, and last longer due to global warming. Heat waves are among the most lethal of extreme weather events, as illustrated by a 2006 heat wave that affected the entire contiguous United States and was blamed for at least 147 deaths in California and another 140 deaths in New York City.
The most common of the greenhouse gasses is CO2 which is a by-product of burning fossil fuels such as coal. At least one half of the electricity in the U.S. is sourced from the burning of coal. Transportation is the second biggest contributor to the greenhouse gas problem.
From the National Resources Defense Council. Steps for better health and sustainable living.
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