Region 6

The EPA Region 6 Area includes Arkansas, Louisiana, New Mexico, Oklahoma, and Texas.  It is one of the most diverse areas of the U.S. and includes coastal areas, deserts, mountains, and plains and faces unique climate change challenges.

Chapter Eleven of the The IPCC Fourth Assessment Report, Working Group I Report, "The Physical Science Basis," provides general regional climate change projections. It projects the U.S. and Canada will experience changes in climate that include temperature, precipitation, and extreme weather events. On an annual-mean basis, projected surface air temperature warming varies from 2°C to 3°C (3.6 ºF to 5.4 ºF) along the western, southern and eastern continental edges.  For the southwestern U.S., it projects warming is likely to be more significant in the summer (as opposed to being more significant in the winter in the northern areas of the U.S.).  Minimum winter temperatures and maximum summer temperatures are likely to increase more than the global annual mean in the southwest. 

The projected warming is expected to be accompanied by a general increase in precipitation over most of the continent except the most south-westerly part, which includes much of EPA Region 6.  For this part of the U.S., annual mean precipitation is very likely to range from remaining unchanged to slightly decreasing. In general, precipitation is likely to be less frequent but more intense.  Snow season length and snow depth are very likely to decrease in most of North America except in the northernmost part of Canada where maximum snow depth is likely to increase.

These trends are graphically displayed here -->

Chapter Fourteen of the The IPCC Fourth Assessment Report, Working Group II Report, "Impacts, Adaptation and Vulnerability," provides some general observations regarding the impacts of climate change to North America.  The U.S. Climate Change Science Program, integrates federal research on climate and global change, as sponsored by thirteen federal agencies and overseen by the Office of Science and Technology Policy, the Council on Environmental Quality, the National Economic Council and the Office of Management and Budget.   It’s reports entitled, “Weather and Climate Extremes in a Changing Climate” and “The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity”  note that changes in extreme weather and climate events will have significant impacts and are among the most serious challenges to society in coping with a changing climate.  Together, these reports note the direct effects of climate change – increased surface air temperatures and changes in precipitation, are projected to result in adaptation challenges.  Based on these findings, due to increasing temperatures, faster evaporation rates, and more sustained droughts brought on by climate change, we can expect:

• A shift towards a warmer climate with an increase in extreme high temperatures and a reduction in extreme low temperatures.  These changes have been especially apparent in the western half of North America
• Abnormally hot days and nights and heat waves are very likely to become more frequent. Cold days and cold nights are very likely to become much less frequent
• Increasing stress due to heat waves.  This may lead to more illness and death, particularly among the young, elderly and frail
• Respiratory disorders may be exacerbated by warming-induced deterioration in air quality
• It is likely that droughts will become more severe in the southwestern U.S., in part because precipitation in the winter rainy season is projected to decrease
• The growing season length is expected to increase.  However, as temperature rises, crops grown in the Southwestern U.S. will increasingly experience temperatures above their optimum, and animal production of meat or dairy products will be impacted by temperature extremes
• Weeds and other invasive plants will continue to migrate northward
• Arid areas are very likely to experience increases in erosion and fire risk
• An increase in the length of the forest fire season and the area subject to forest fires
• Additional stress to ground water and surface water sources that are already overtaxed in many areas
• Changes in the abundance and spatial distribution of species, and expanded ranges of tree killing insects, vector-borne and tick-borne diseases
• Precipitation is likely to be less frequent but more intense and precipitation extremes are very likely to increase
• Management of Western reservoir systems is very likely to become more challenging as runoff patterns continue to change
• Increased weather related losses of property
• Rising seal level in and around the Gulf Coast area
• It is likely that hurricane intensity will increase in response to human-caused warming, but this requires further study