Climate report forecasts smaller, hotter Maryland

The Baltimore Sun

Look for balmier winters and blistering summers in the decades to come. Enjoy the colorful fall foliage in Western Maryland - while you can. And unless circumstances change, prepare to see a different mix of plants, trees and birds by the end of the century, worsening dead zones in the Chesapeake Bay, and for the state that some call "America in miniature" to get dramatically smaller as rising waters push the shoreline inland.

So says a group of scientists who have compiled the first comprehensive assessment of how Maryland could be altered by global climate change.

Their report, a copy of which was obtained by The Sun, was prepared to help state policy-makers and lawmakers develop responses to the sweeping impacts.

The scientists' assessment suggests that some of the expected changes may appear benign at first, but many others could have drastic consequences.

"The good news is we'll have winters like Charleston, South Carolina," said Donald F. Boesch, president of the University of Maryland Center for Environmental Science and editor of the report. "The bad news is we'll have summers like Phoenix, but with humidity."

Similarly, the report suggests that the state's gardeners and farmers might benefit for the next several decades as rising temperatures lengthen the growing season. But crops and gardens could suffer later in the century as hotter weather dries out the soil and stresses plants.

The report, produced for the state Commission on Climate Change, was researched and written by a committee of 19 scientists from five Maryland campuses, the U.S. Geological Survey and two environmental groups. They include specialists in marine science, oceanography, physics, hydrology, ecology, geology, biology and epidemiology.

The committee drew from new and previous research on global and regional climate change, including the latest report, in 2007, by the Intergovernmental Panel on Climate Change, an international scientific body set up by the United Nations.

The Maryland group also considered many supercomputer model projections, selected for how well they replicated actual 20th-century conditions in the state.

The commission, appointed last year by Gov. Martin O'Malley, is expected to recommend measures to prepare the public for the unavoidable impacts of already rising global temperatures and sea levels, as well as to limit warming by reducing emissions of carbon dioxide and other so-called greenhouse gases.

Maryland is among a growing number of state and local governments that are taking action on their own to assess the impact of climate change. Among other initiatives, the state recently joined the Regional Greenhouse Gas Initiative, a group of Northeast and Mid-Atlantic states that are cooperating on strategies to reduce carbon dioxide emissions from power plants.

Shari T. Wilson, Maryland's environment secretary and the chairwoman of the climate commission, said the panel expects to present a menu of 42 policy responses to the governor this month.

Some, such as the administration's push to increase energy efficiency and production of renewable power, are already under way and should reduce emissions over the next decade, she said. Others, such as expanding public transportation use, could take longer to produce significant results and cost more up front.

"This issue and the reductions cut across every sector of the state, whether it's transportation or energy. It affects everybody," said Wilson.

Any state legislation attempting to curtail carbon dioxide emissions is likely to be controversial. An administration-backed bill that would have committed the state to reducing releases of heat-trapping gases 90 percent by 2050 failed this year in Annapolis. Manufacturers and labor unions warned that it could drive industry from Maryland and cost jobs.

The governor has yet to see any of the commission's reports but looks forward to reviewing them, said his spokesman, Rick Abbruzzese.

"All of this has to be considered with all the stakeholders involved, keeping in mind the national economy and the budgetary issues the state faces," he said. "We'll have to make some decisions on how quickly we can move forward."

But the sooner action is taken, the more likely it is society might temper the impacts, said Boesch: "Given what it takes to stabilize greenhouse gases, time is of the essence."

Among the report's findings:

* An increase in the average annual temperature in Maryland of about 3 degrees Fahrenheit by midcentury is "likely unavoidable;" if greenhouse gas emissions go unchecked, summertime averages could soar by up to 9 degrees, with heat waves lasting practically all summer and 24 days with highs above 100 degrees.

* Increased health risks, particularly for the elderly, the young and those with respiratory problems, due to both heat stress and air pollution aggravated by hot weather;

* The maple, beech and birch trees in forested Western Maryland are likely to "fade away," the report says, while pine trees more common in southern climes come to dominate the woodlands.

* As many as 34 bird species, including the signature Baltimore oriole, could be forced northward, while birds such as the cardinal and indigo bunting, seen more often to the south, become more common here.

The scientific group also focused on the potential impacts of sea-level rise for Maryland's 4,400 miles of shoreline. The waterline here has already risen by a foot since 1900, through a combination of surging waters and the land slowly sinking. Land subsidence likely will continue at the same rate, the scientists project, but sea-level rise is expected to accelerate during the coming century.

Shoreline erosion has already claimed many islands and broad stretches of wetlands in the Chesapeake - and spurred many Marylanders to armor their shorelines with bulkheads - with deleterious impacts on water quality, shoreline habitat and wildlife.

When the climate models add the impact of melting Arctic ice, the projected rise in sea level jumps to three feet by the end of the century. If so, the panel concluded, "most tidal wetlands would be lost - about 200 square miles of land would be inundated," reverting to open water. Migration of wetlands to higher ground would not replace what is lost.

Smith Island and portions of Talbot, St. Mary's, Anne Arundel and Baltimore counties could be inundated or cut off.

An 18-inch rise in sea levels would drown 264 miles of roads, 226 miles of rail and 31 percent of Baltimore's port facilities, the panel noted.

The panel urged that Maryland's long-range planning accommodate a 1-foot rise in sea level by midcentury and 2 feet by 2100. If emissions are not curbed, it would be "prudent" in long-term infrastructure planning to anticipate a 4-foot rise in sea levels a century from now.

As temperatures climb, cool-water northern species in the Chesapeake estuary, such as soft-shell clams, sturgeon and eelgrass, are likely to disappear, while warm-water species - such as Atlantic croaker - would benefit. Crabs might prosper from higher salinity and warmer temperatures.

"Summertime water temperatures are likely to be similar to those of the North Carolina sounds by 2050," the panel said.

By 2100, they'll feel like South Florida.

With added runoff, that will expand "dead" zones, where nutrients in sediments lead to algae blooms, decay and reductions in dissolved oxygen.

On the plus side: Icing across the Chesapeake Bay - formerly a once-in-10-years event - may become as rare as once in 25 to 40 years, the committee said. That could aid oystermen and bay navigation.

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