The impact of global warming in Montana

By JACOB GOLDSTEIN Chronicle Staff Writer

Kelly Redmond has been studying Montana's climate since he was a boy, when his father took the daily weather readings at Gallatin Field.

For Redmond, a fascination with climate was just part of growing up in a weather-obsessed state:

"If you're not interested in the weather in Montana, basically you're in a cemetery," he explained.

But unlike most armchair weathermen, Redmond earned a Ph.D. in meteorology and landed a federally funded job studying climate in the West.

Like many scientists, Redmond believes the weather in Montana will probably get warmer in the coming decades, and that certain consequences -- including a reduction in average annual snowpack -- are likely to accompany that trend.

Not all experts agree with Redmond's predictions. But many of those who are skeptical of his views agree that human activities -- such as the burning of fossil fuels, which releases carbon dioxide into the atmosphere -- are likely to have some effect on the world's climate, and that Montana's weather will change in some unpredictable way.

Redmond's predictions are based on the assumption that temperatures worldwide will increase in the coming years.

"That's the most confident thing we can say," he said.

A climate change report issued two years ago by the National Academy of Science began with the statement, "Greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures ... to rise."

The largest changes in the U.S., Redmond said, are likely to be in Western states, during the winter, in higher latitudes -- all of which would impact Montana.

"If the temperature got warmer," he continued, "the snow would be falling over a fewer number of months per year."

This would mean a decline in snowpack -- a change that would would upset the current system, in which runoff from the snow that falls during winter provides most of the water used in the dry summer months.

"It's a beautiful structure the way it works right now," Redmond said. "It's a big white reservoir. It's draped over the tops of the mountains. It didn't require any structures to be put in place."

Gretchen Rupp, the environmental engineer who heads the Montana Water Center, was more succinct:

"If we see warming, we will get more winter precipitation in the form of rain rather than snow, which means lessened snowpack, which means less surface water available to us in the summer."

Many experts agree that the scenario described by Rupp and Redmond is likely. But water managers and users in Montana have taken little notice, according to Rupp.

"I haven't heard us talking about it in Montana," she said. "We're scrambling so hard to deal with things on a month-to-month and year-to-year situation."

Rupp added that in the absence of dramatic climate changes, action on the part of the agencies that manage water will be unlikely.

"When a space shuttle explodes, we instantly appoint a commission and spend millions of dollars," she said. But in the case of climate change, "we're not going to see any explosions. We don't have good ways of dealing with this kind of change."

Another reason for the lack of action is the skepticism that remains in many parts of the professional community.

The American Association of State Climatologists' official policy says, "climate predictions have not demonstrated skill in projecting ... changes in such important climate conditions as growing season, drought, flood-producing rainfall, heat waves, tropical cyclones and winter storms."

"We have no confidence in what the future climate is going to be," said Roger Pielke, the Colorado climatologist who serves as the group's president.

But Pielke, like many of those who put little faith in the specific predictions of climate models, agrees that changes are in store.

"The very (phrase) 'climate change' is almost redundant," Pielke said. "Every century in the last thousand years is different."

The 20th century was characterized by an unusually stable climate, according to Lisa Graumlich, a Montana State University scientist who has studied tree rings to compile centuries of climate data for the Western U.S.

"We've been really lucky for the last 100 years," Graumlich said.

The historic record clearly shows that decades-long "megadroughts" have periodically afflicted the West during the last millennium -- events "that make the Dust Bowl look like a picnic," she said. A 16th-century drought lasted for 40 years and affected regions from Montana to Mexico, tree-ring data suggest.

A highly variable climate is bad news for farmers, said Carl Mattson, a Custer farmer who served two years ago on a federal committee that studied the impacts of climate change on American agriculture.

Mattson explained that variability makes it difficult for farmers to predict what their income will be.

"If you have a job and someone says, 'We might be able to work you half time or we might be able to work you full time,' suddenly that affects what you might be able to do in life," Mattson said.

The committee Mattson served on was composed mostly of scientists; he was one of a few "stakeholders," whose role was to explain to scientists the implications of various changes in climate.

The group reviewed models that predicted a range of climactic changes, according to Mattson, but all of the models suggested increased variability and more dramatic weather.

"The highs would be higher, the lows would be lower, the drought would be longer, the wet spells would be wetter," he said.

Pielke noted that even those climatologists who are skeptical of specific predictions believe human activities will have an impact on global climate.

"We are convinced that humans are disturbing the climate system," he explained. "We can be confident that we are altering the climate, but in unknown, unforeseen ways."

Redmond said scientists need to collect more data to improve the predictive power of their models, and to consider human impacts -- such as changes in land-use patterns -- that go beyond carbon-dioxide emissions.

But he emphasized that atmospheric levels of carbon dioxide will almost certainly continue to increase, and that the increase will have an impact on the world's climate.

"This is a genie we can't put back in the bottle," he said.

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