Warmer Temperatures
Average temperatures are on the rise, resulting in more frequent heat waves.Examples to show that the world is heating up:
- United States has already become warmer, in some areas by as much as 4 degrees Fahrenheit. In fact, no state in the lower 48 states experienced below average temperatures in 2002. The last three five-year periods are the three warmest on record.
- Many places in North America had their hottest seasons or days on record in the late 1990s.
- Since 1980, the earth has experienced 19 of its 20 hottest years on record, with 2005 and 1998 tied for the hottest and 2002 and 2003 coming in second and third.
Drought and Wildfire
Warmer temperatures could also increase the probability of drought. Greater evaporation, particularly during summer and fall, could exacerbate drought conditions and increase the risk of wildfires.Examples to show:
- The 1999-2002 national drought in the USA was one of the three most extensive droughts in the last 40 years.
- In 2002, the Western United States experienced its second worst wildfire season in the last 50 years; more than 7 million acres burned. Colorado, Arizona, and Oregon had their worst seasons.
- The period from April through June of 1998 was the driest three-month period in 104 years in Florida, Texas, and Louisiana.
- Dry conditions produced the worst wildfires in 50 years in Florida in 1998.
- April through July of 1999 was the driest four-month stretch in 105 years of record-keeping in New Jersey, Delaware, Maryland, and Rhode Island.
- Montana, Colorado, and Kansas experienced severe dust storms in 2002, a product of dry conditions.
- September 2001 to February 2002 was the second driest six-month period on record for the Northeast.
More intense rainstorms
Warmer temperatures increase the rate of evaporation of the climatic system and lead to more intense rainfall at some times and in some areas.Examples to show:
- National annual precipitation has increased between 5 and 10 percent since the early 20th century, largely the result of heavy downpours in some areas.
- Vermont, New Hampshire, Rhode Island, and Massachusetts each got more than double their normal monthly rainfall in June 1998.
- Severe flooding in the Texas, Montana, and North Dakota during the summer of 2002 caused hundreds of millions of dollars in damage.