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Climate of the future?

Researcher will try to predict it by simulating global warming

Jeff Dukes wants to know what New England will look like in a warmer, wetter world. So, the biology professor at the University of Massachusetts at Boston will spend five years simulating future climatic conditions on an old farm in Waltham.

During the $1 million Boston-Area Climate Experiment at the university's agricultural facility on Beaver Street, ceramic heaters will warm 2-square-meter plots of earth to simulate the effects of global warming. Corrugated polycarbonate roofing panels and sprinklers overhead will control the amount of rain that reaches the ground over specific plots.

The overall temperature in the Northeast in the next century may increase 4, 7, or 12 degrees, according to some scientists. But no one knows for sure.

The climate experiment will vary the temperature and rainfall amounts within 36 individual plots. In other words, Dukes is shaping three dozen microclimates -- some wetter, some drier, some cooler, some hotter -- that do not yet exist in New England.

Dukes will study how the climate changes affect the growth of grasses and wildflowers, as well as microbes in the soil.

But first he must find a way to keep the lid over his experiment.

"The storm just ripped our roof off," Dukes said as he stood in the field at the agricultural facility.

Last month's northeaster had torn gaping holes in the greenhouse-like roofs he had built above three rows of plots. "Those slats that are double-wide did just fine. So we're going to use those instead."

That means that Dukes and his technicians and grad students in the Dukes Lab at UMass may need to recalibrate their experiment and pipe in more water to those spots that will get less rain passing through the wider slats.

Old fields like the one in Waltham can return to forest land over hundreds of years. Dukes's group will plant tree seedlings on some of the plots next year to study their growth.

Dukes suspects that ecosystems have certain warming thresholds at which plant and microbial growth "become less predictable." At some point, one species might crowd the others out or all the species might suffer.

The Boston-Area Climate Experiment is Dukes's attempt to find those tipping points.

Dukes's research begins with the premise that global warming is actually happening and that man probably has a contributing role.

"We start with global warming as a given," he said.

In an ironic twist, Dukes expects the electric bill for keeping the ceramic heaters on 24 hours a day, seven days a week, to cost at least $60,000 a year. The National Science Foundation and US Department of Energy are funding the experiment.

"Jeff is one of the leading global-change and plant-ecology scientists in the world," said US Department of Agriculture plant physiologist Jack Morgan, who has visited the Waltham site. "His research is very solid."

Morgan is studying the effects of elevated carbon dioxide and temperatures on Great Plains rangelands with experiments in Colorado and Wyoming. He said he believes that rising carbon-dioxide levels are changing rangelands, making them less useful for livestock grazing because of the encroachment of "woody plants and a decline in forage quality."

Ranchers and scientists in the United States, Australia, Europe, and South Africa have long attributed the problem -- marked by the encroachment of a particular shrub -- to overgrazing and a lack of wildfires in densely populated areas.

"But if CO{-2} is in part driving this," Morgan said, "that's not something that is going to go away by itself. It's important that we anticipate these conditions."

The USDA's Agricultural Research Service, at ars.usda.gov, and for which Morgan works, aims to assess "agriculture's role as a source or sink in greenhouse gas emissions" and to create models to project how crops and animals would respond to climate change, according to the research service's website.

"My job and Jeff's," Morgan said, "is to provide the science so policy makers can make intelligent decisions."

Some climate experiments, like Dukes's project, also are intended to present the public with a tangible experience of some likely scenarios.

Visitors to the Waltham site soon will be able to explore demonstration plots that will show plant species as they thrive, or die, in a warmer climate.

The public, even some scientists, still have not been convinced that global warming is real, said Novem Auyeung, a doctoral student in Dukes's l ab who will study how microbes in the soil are affected by changes in temperature and rainfall.

Auyeung gets surprised looks when she tells some of her friends about the project. "They say, 'But aren't there scientists who don't believe global warming is happening?' "

There are "fewer and fewer scientists in that category," said Auyeung, who said the evidence for the phenomenon is massive.

Dissenters, even if their science is shaky, can disproportionately affect the global warming debate, Auyeung said.

"They stand out," she said. "They are the ones you remember. It's like when you've had a bunch of bad days in a row, you remember the one good day, that the sun was shining."

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