The latest and most detailed climate model of the continental U.S. predicts temperatures so extreme by the end of the century they could substantially disrupt the country's economy and infrastructure. The climate simulation, churned out by supercomputers at Purdue University, factors in dynamic environmental variables previously unaccounted for and analyzes them at a resolution twice as fine as previous models. The results indicate an increase in heat, heavier rainfalls and shorter winters, which could strain water resources for people and crops and cause a catastrophic loss of life and property, among other things.

"Climate change is going to be even more dramatic than we previously thought," says Noah Diffenbaugh, who reported his team's findings in the October 17 online edition of the Proceedings of the National Academy of Sciences. Until now, the fastest computers crunching climate data and using the most sophisticated computer codes have produced only a grainy image of the country's climate picture. For one thing, the codes--which incorporate data describing hundreds of natural variables such as ocean currents, cloud formation, vegetation cover and the amount of greenhouse gases expected to exist in the atmosphere--have left out such factors as soil moisture, how much sun snow-cover reflects, and to what extent mountains thwart weather systems. What is more, previous models calculated the data by breaking the country into a grid of 50-kilometer squares, a resolution that can miss climatic nuances.

Diffenbaugh's model incorporates the additional natural variables and does so at a resolution of 25-kilometer grid squares. The smaller squares provide a higher resolution and a better picture of what is in store for the country by the end of the century. Assuming that human-generated greenhouse gases attain concentrations more than twice their current level, Diffenbaugh's model predicts several events: the desert Southwest will have more frequent and intense heat waves, combined with less precipitation during the summer; the Gulf Coast will grow hotter and experience heavier rainfalls in short time periods; the Northeast will suffer under longer, hotter summers; overall, the continental U.S. will undergo a warming trend that will reduce the length of winter.

To confirm the model's accuracy, Diffenbaugh ran it using weather data from between 1961 and 1985 and compared the prediction with what actually occurred. "The model performed admirably, which tells us we've got a good understanding of how to represent the physical world in terms of computer code," he comments.

Weather-related extremes such as floods, hurricanes and heat waves have lead to loss of lives and property. Hurricane Katrina alone claimed more than 1,000 lives and Congress has already set aside $62.5 billion for relief and rebuilding efforts. One heat wave during the summer of 1995 took 1,100 lives and the government spent $88 billion between 1988 and 1993 on three weather-related disasters (drought and flooding in the Midwest and Hurricane Andrew). Although the new results are alarming, they are not meant to create an alarmist view, Diffenbaugh explains. Rather they forecast a scenario that should be taken under serious consideration.

6 Comments

1. 1. hotblack 08:44 PM 6/18/08

   Ok, I'll get it out of the way for the nutters... Jesus did it, to punish liberals. Happy now?
   
   What is interesting about temperature change, & not water level change, is how it affects our nations human migratory patterns, both in terms of comfort and in terms of the relationship between food supply and cost of living. Interesting.

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2. 2. Bradley 05:33 AM 6/19/08

   Please consider that you cannot make the climate model in question more useful, more accurate, or more relevant by making attacks on other people's character.
   
   There is no indication from your comments that you understand this model any better than your target stereotypes. I don't think the readers will profit from your propensity to turn the issue away from the model and toward antisocial commentary on people who [i]might[/i] disagree with your opinion, whatever it may be.
   
   Neither you nor I can demonstrate that we understand the issues by pointing at someone else and claiming they are mentally ill, even if they are.
   
   Not all Christians are unaware of or religiously opposed to the possibility that human activity may be adversely affecting global climate.
   
   It is a grave error to make such prejudicial comments about a very large group of people, many of whom may have confidence that global warming is a real threat that must be addressed aggressively.
   
   If people agree with an opinion they do not understand, solely to be part of the ingroup, that is not helpful in educating people about climate change. It is about at the level of the kind of rhetoric Rush Limbaugh engages in.

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3. 3. fishman 11:57 PM 4/24/09

   If you placed the new doun turn in temps there could be a demi ice age at the end of this century. That is why short term models have proven they are not worth the time to do them. Some of these models unravel when they are run out just 150 years. Project the model out and the end of the earth is in sight.

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4. 4. pgtruspace 02:45 AM 6/3/09

   How well did the the model predict the actual events of the 1985 to 20o8 period. The model was built with 1961 to 1985 data and predicted the corrected events of the 1961 to 1985 period. Well dah...................
   And if the CO2 is doubled and the over all temperature increases, the U.S. is warmer, wetter, with longer growing seasons and faster plant growth (due to higher CO2) What is the down side? so the beach front will change.
   Over the last 6,000 years history teaches us that warmer is better and cooler is bad, colder very bad for all life.
   

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5. 5. deepinelastic 01:14 AM 4/16/10

   Just quickly, if there is going to be a lot more rainfall, why will there be less water resources? You have heard that water is trapped in reservoirs to provide water for the humans around. Why is more rainfall catastrophic? We could have 5 times more in California most years and not notice it. How about Arizona or Nevada. Let's not talk about Washington and Oregon.
   And I thought you have real problems simulating clouds and rain generation. Do you layer the atmosphere and solve a three dimensional hydrodynamic differential equation or do you simplify, simplify, simplify as usual. Linearizing equations can work for short times but are useless over something like 100 years. Be honest with us. Criticize your own work and let us understand where the weaknesses are. Then we will be able to evaluate what your calculation has to offer.

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6. 6. deepinelastic 01:16 AM 4/16/10

   Just quickly, if there is going to be a lot more rainfall, why will there be less water resources? You have heard that water is trapped in reservoirs to provide water for the humans around. Why is more rainfall catastrophic? We could have 5 times more in California most years and not notice it. How about Arizona or Nevada. Let's not talk about Washington and Oregon.
   And I thought you have real problems simulating clouds and rain generation. Do you layer the atmosphere and solve a three dimensional hydrodynamic differential equation or do you simplify, simplify, simplify as usual. Linearizing equations can work for short times but are useless over something like 100 years. Be honest with us. Criticize your own work and let us understand where the weaknesses are. Then we will be able to evaluate what your calculation has to offer.

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