SOUTHERN DISCOMFORT:

Ready or Not, Global Warming Effects Are Being Felt Now

By MELANIE FITZPATRICK

We can plan for the effects of changes that are now taking place, and we can develop ways to mitigate predicted damage. But will we do this?

These and many other impacts of a changing climate are outlined in a new report released last October by the Union of Concerned Scientists and the Ecological Society of America. Confronting Climate Change in the Gulf Coast Region: Prospects for Sustaining Our Ecological Heritage examines how climate change will interact with the many pressures already changing ecologies in the five Gulf states.

This bountiful coastline, stretching from Texas to Florida, is rich with ecological resources that support the region's economic wealth. But human activity has dramatically altered the natural landscape. The population of the Gulf states has increased by 20% over the last 10 years, and the coastal population is projected to rise by 44% over the next 25 years. This explosive growth places enormous pressures on the ecosystems in this region. Climate change, driven by increasing levels of heat-trapping gases in the atmosphere, will magnify the impacts of these human stresses.

The Future of Water

Water is essential to the continued health of the region's ecosystems—arid the many industries dependent on them. The seasonal summer rainfall, the powerful coastal storms, and the underground aquifers in the Gulf coast region are reminders that water sustains and shapes the land. Both natural and managed ecosystems depend heavily on the availability of water, which links the uplands, the lowlands, and the coastal ecosystems. Scientists predict—based on climate models—that this region is likely to see significant changes in its water resources.

Climate models predict warmer temperatures along the Gulf Coast and an increasing rate of sea level rise over the next 100 years. The climate system is complex, however, and not all aspects are easy to model. In particular, predicting the amounts and locations of future rainfall is challenging. With this caveat, rainfall is likely to decrease in the coastal areas of all the Gulf states except parts of Texas, but it is uncertain whether the states' upland areas will be wetter or drier.

Regional Warming. Average temperatures in the Gulf Coast region have shown a warming trend since the late 1960s. Models predict that this trend will continue, with summer maximum temperatures increasing by 3 to 7†F, and winter minimums rising 3 to 10†F over the next century. This will dramatically increase the July heat index, decrease the number of winter cold spells, and move the frost line northward.

With increasing summer temperatures, major metropolitan areas, such as Houston, New Orleans, and St. Petersburg, will be particularly vulnerable to more heat waves. Air quality will deteriorate, exacerbating asthma and other respiratory diseases. The number of heat-related illnesses and deaths will increase, particularly among the elderly and infirm and those who cannot afford air conditioning.

Droughts, such as the 25-month-long drought Louisiana experienced in 1998-2000, may be more common. More frequent droughts will drastically affect the agricultural areas, which are sensitive to water availability and temperature. Water-intensive crops like rice, cotton, soybeans, and sugarcane will raise serious concerns about water allocation between upland and coastal areas.

Warmer temperatures will also affect forest industries in the Gulf Coast region, which produces almost half the timber from the southeastern United States. Drier conditions would increase the risk of wildfires in natural and managed forests and could change the species favored from those of forests to those of savannahs and grasslands. Disturbance and drought may assist the establishment of non-native species such as the Chinese tallow tree, which can transform a diverse coastal prairie into a biologically impoverished forest in just 30 years. If conditions become wetter, warmer average temperatures and milder winters would increase the prevalence of pests such as the Southern pine bark beetle. Heavy downpours may lead to inland flooding, soil erosion in the uplands, and subsequent nutrient enrichment in rivers and coastal areas. This increased runoff could result in algal blooms in rivers and low-oxygen conditions in coastal waters that may kill fish or displace them to healthier habitats.

Rising Seas. Ocean temperatures are likely to continue warming in the future. Warming water expands in volume, and this expansion of the world's oceans is the major reason that sea level is rising. Over the last century, sea level has risen between 8 and 40 inches along different regions of the Gulf Coast, due to global sea level rise and substantial local sinking of land. Taking into account continued land subsidence, climate models predict that sea level along the Gulf Coast is likely to rise by another 15 to 40 inches by 2100.

Flat topography and extensive shoreline development already make the Gulf Coast susceptible to flooding, erosion, and property damage. Rising sea level will only increase its vulnerability. In many areas, such as the barrier islands, sea level rise already threatens homes, roads, and community infrastructure. Hurricanes and tropical storms could become more intense; but even if they do not, storm surges and coastal flooding will be more damaging simply due to higher sea level. Of the 20 busiest US cargo ports, I I are found in the Gulf Coast region, including New Orleans, Galveston, Mobile, and Tampa. All of these facilities will be seriously affected by increased storm damage and sea level rise.

Global warming? It's happening now—not just along the Gulf Coast, but along our precious Chesapeake Bay and other shores.

Practical Solutions

Addressing the potential impacts of climate change will challenge communities and government alike. Policy-makers, local planners, and residents can act now to develop a prudent and responsible approach. Actions to slow climate change include reducing fossil fuel dependence and introducing the clean technologies of solar, wind, and bio-energy. A variety of methods can minimize human impact on ecosystems-among them implementing "best practices" such as conserving water and reducing farm runoff. Such actions yield economic benefits, as well as helping to preserve ecosystems.

Industry and communities can also adapt to changes already under way. Adaptation requires a flexible approach to such things as seasonal variability in water or changes in soil moisture and nutrients.

Most important, people need to be made aware of the fragility of Gulf Coast ecosystems in light of a changing climate. This report, and intensive outreach by UCS and others, are contributing to that effort. With public support and strong leadership, the Gulf states can plan and act to ensure the region remains a vibrant ecological and economic community.

Reprinted from the Spring 2002 issue of "Catalyst" with permission of The Union of Concerned Scientists, a nonprofit partnership of scientists and citizens combining rigorous scientific analysis, innovative policy development and effective citizen advocacy to achieve practical environmental solutions. "Catalyst," a magazine, is financed by contributions from individual members; you can join UCS by sending a tax-deductible contribution of $25 or more to UCS Development, Two Brattle Square, Cambridge, MA 02238-9105. Call 617-547-5552; see http://ucsusa.org