Climate Change and You

Butterflies are highly sensitive creatures, especially when it comes to changes in climate. So several years ago Dr. Camille Parmesan, a population biologist from the University of Texas, Austin, decided to investigate whether they could tell us something about global climate change. She found that 37 species of nonmigratory butterflies in Europe, and one species in the western Americas, have shifted their geographic ranges in correlation to changes in climate. Many of these species have moved both poleward and higher in elevation.

This implies that even a small change in mean temperature can have a big effect on wild organisms, Parmesan says. "It's probably a signal of what's going to start happening in lots of other organisms," she adds. While the effects are still small, from a human perspective, there's a lot we can do to prevent bigger change.

The Earth Is Warming

The scientific consensus is that global warming is underway, caused by a phenomenon known as the "greenhouse effect." Certain gases, such as carbon dioxide (CO2), methane, chlorofluorocarbons and nitrous oxide, accumulate in Earth's atmosphere and, like glass, trap heat close to its surface. These gases are both naturally occurring and a result of human activity: burning fossil fuels (coal, oil and natural gas), cutting forests, and farming.

Climatologists say that the planet has warmed by 0.72°F to 1.08°F during the past century, in which the 1990's were the hottest decade. A temperature hike of 3.5°F, the most likely number for the next century, would cause extreme climate changes. The frequency of floods and drought is likely to increase. Glaciers will melt, while ocean temperatures and sea level will rise. Flooding may force people to move away from low lying coastal areas. Plants and animals adapted to cooler climates may die out or be pushed north. Parmesan's butterfly studies are the first to document such a shift.

3 Ways to Help

We have a chance at countering global warming if we do the following:

1) Reduce Use of Fossil Fuels:

Dr. Parmesan drives a Honda Civic because it's more fuel efficient and emits less CO2. For example, a 2000 Honda Civic sedan gets 35 miles per gallon in the city, while a 2000 Ford Explorer sport utility vehicle gets less than half that. Parmesan also suggests that we reduce our use of fuel-guzzling air conditioners and heating. "Try to be more comfortable in a wider range of temperatures," she says.

2) Plant and Conserve Trees:

Trees reduce CO2 in the atmosphere through photosynthesis, taking up CO2 in their leaves and converting it into carbon in the tree's biomass -- the trunk, branches and roots. Slower-growing trees, which live longer, will store more CO2 than a fast-growing, short-lived one. Cutting old-growth forests causes major carbon release as the wood decomposes over time. By choosing certified sustainably-forested wood, consumers encourage management practices such as replanting trees, and preserving old growth.

To maximize CO2 reduction when you plant a shade tree, "The best place is to the west, northwest or southwest of a building -- it provides the biggest cooling benefit," says Greg McPherson of the U.S. Forest Service. Planting evergreens as wind barriers will lower heating costs, he adds.

3) Support Organic Farms:

Improved agricultural practices can reduce the amount of CO2 in our atmosphere. These include such organic farming techniques as increasing the use of cover crops, crop rotations, and using organic manure as fertilizer. By returning organic matter to the soil, such methods in the U.S. can keep up to 200 million tons of CO2 per year out of the atmosphere, says Rattan Lal, Ph.D., professor of soil science at Ohio State University. "These improved farming techniques could meet up to one-third of the U.S. commitment under Kyoto," Dr. Lal says, referring to an international agreement to cut greenhouse gas emissions beginning in 2008. The U.S. Senate has yet to ratify the Kyoto Protocol.

But ultimately, Lal cautions, "The ability of soil to hold carbon is finite, so once that reservoir is full we must find another means of sequestering carbon." But efforts to increase carbon storage in soil and forests can buy us time to make needed bigger public and private sector changes.

Cooler Business

As governments address greenhouse gas reductions, there's debate over industry's role. Today, U.S. industry is responsible for 35% of the country's CO2 emissions. Given such a high percentage, many policymakers recognize the crucial role industry could play in mitigating climate change.

In recent years, a number of companies have shown that, by redesigning their energy systems to burn less fossil fuels, they've been able to cut costs while increasing productivity and profitability. In 1998, the U.S. experienced the smallest increase in greenhouse gas emissions since 1991, yet the economy grew by 4%. A Department of Energy official commented that 1998's warm winter and a slowdown in some sectors of industrial production may have caused some of the emissions decline.

In any case, we still need reductions: The U.S must cut back its emissions of greenhouse gases 7% from 1990 levels if it is to meet the terms of the Kyoto Protocol. But U.S. emissions are currently 10% above 1990 levels.

A problem as big as the Earth itself can seem overwhelming. One energy policy expert, when asked what individuals can do to reverse climate change, just laughed and said, "pray ... or meditate on a picture of Antarctica every day." True, one Honda Civic on a highway clogged with SUV's won't turn down Earth's thermostat. But it's our combined efforts that make a difference, politically, in the marketplace and at home.

Nancy Cohen is a freelance environmental writer.