Extreme Weather and Climate Change: The Southwest
WHAT WE KNOW
Devastating deluges, record floods and deadly heat waves have raised the question of whether there’s a connection between these events and global warming.
The bottom line answer is yes: Heat waves are longer and hotter than they used to be and some regions are suffering from catastrophic drought. Heavy rains are morefrequent and can be more intense and rainfall records have been smashed. These events fit a pattern that climate scientists have long expected to appear as the result of increased greenhouse gases in our atmosphere. That doesn’t mean global warming is the only culprit: extreme weather was happening before global warming began. But there’s general scientific agreement that global warming has contributed to a trend toward more intense extremes of heat and precipitation around the world, is partly to blame for specific extreme weather events over the last decade and will continue to influence both in the future.
Number of days the maximum temperature exceeded 100 °F. credit: NOAA/NCDC.
Extreme Heat and Drought of 2011
Texans love to brag about how big their state is along with everything in it. Not so much this year, though, as record-breaking heat, drought and wildfires relentlessly pummeled Texans. The heat struck nearby Oklahoma, Louisiana and New Mexico too, pushing all of the states’ resources, along with their residents, to the brink of disaster—and in many cases, right over the edge.
Scientists know that climate change is making heat extremes like
those experienced in the Southwest this year more intense
and more frequent.
HEAT RECORDS BROKEN
In August alone, Texas broke >4,000
Their Hottest Summer On Record
>100 Days over 100° F
86 Days over 100° F
90 Days over 100° F
Hottest Summer in US History
What happened in 2011:
Texas, Oklahoma, New Mexico and Louisiana had their hottest summers on record this year.
Texas had the warmest summer of any state in the U.S. going back to when modern records began in 1895 and set more than 4,000 hot temperature records in August alone. Oklahoma came in second and both states beat records set during the Dust Bowl era in the 1930s.
Nationally, the ratio of record highs to record lows this summer was 4.35 to 1. But in Texas, the ratio was 80 to 1.
In Texas, the average statewide temperature for the summer (night and day) was a whopping 86. 8°F.
- Every state in the Lower-48 except North Dakota and Vermont had at leastone day with a temperature topping 100°F. Many cities broke all-time heat records. Austin, Texas set newrecords for the most 100° days, the hottest month, the hottest summer and the hottest day in history (112°F, tied with Sep, 5, 2000).
Texas Drought and Wildfires
DROUGHT & WILDFIRE RECORDS BROKEN in 2011
Worst One-year Drought On Record
Number of Acres Burned in:
Climate change is creating drier conditions in the American Southwest,(15) and has been linked to increases inforest acres burned in some regions of the West.(8,16)
These drier conditions are aggravated by natural climate cycles, such as La Nina, a significant factor in this year’s drought, which tend to favor drought in the Southwest. Global warming could boost the intensity and impact of these La Nina-related droughts.(18,19,20)
- For every additional degree of global warming, the number of acres burned in Southwest wildfires is projected to increase dramatically — at the same time as rain and snowfall decrease.(17)
At the end of September, 97 percent of Texas was in one of the top two most severe categories of drought, according to the U.S. Drought Monitor. That’s a new state record.
Drought and extreme heat combined to create Texas’ worst wildfire season on record, with nearly four million acres burned so far.
Texas broke a record for the driest 12-month period on record. The drought has cost Texas an estimated $5.2 billion in agricultural losses and at least $1 billion in other damage, making it the most costly drought in the state’s history.
Bastrop State Park as a wildfire burns out of control
The drought is driving up the price of beef as ranchers are forced to sell their herds early. Lower cotton yields could force up cotton prices and peanut, corn and wheat crops have also been hit hard.
The Bastrop fire, which ignited east of Austin on September 4, burned over 34,000 acres, killed two people and destroyed more than 1,600 homes, breaking the state record for the most homes lost in a single wildfire. It was also the most expensive wildfire in Texas history.
New Mexico also suffered from unusually severe wildfires. At one point, the Las Conchas wildfire, which burned nearly 130,000 acres, threatened the Energy Department’s Los Alamos National Laboratory, the birthplace of the atomic bomb.
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