Archive for the ‘climate change’ Category

Global Warming: A Doubling of Tree Deaths

Sunday, January 25th, 2009

More bad news: According to a new study published in the current issue of Science, tree deaths in old-growth forests throughout the American West have more than doubled in recent decades. During the past decade, for example, mountain pine bark beetles have killed roughly 3.5 million acres of lodgepole pine forests in northwestern Colorado, and spruce bark beetles have also killed large areas of spruce forest in northern and southwestern areas of the state.

The study’s authors ruled out a number of possible reasons for the increasing die-offs, including air pollution, long-term effects of fire suppression, and normal forest dynamics, while concluding that regional warming and related droughts were the likely causes. Scarier still is their speculation that these deaths could lead to a series of harmful “cascading effects” on wildlife, and even more carbon dioxide in the atmosphere as there are fewer trees to absorb it and as the dead trees decaying on the forest floors become a significant source of the greenhouse gas.

Global Warming: The Blog Epic

Thursday, January 22nd, 2009

What the heck does all the new data on global warming mean? For some perspective, take a look at one scientist’s very readable primer on climate change. Greg Laden, a biological anthropologist, provides not only good background but also cool facts. Here’s Laden on the major greenhouse gas:

Carbon Dioxide is a deadly poison. It is about 50% heavier than air, so where it occurs in density, in mines or certain natural vents associated with volcanics, it can accumulate in low spots. There are places in the Western Rift Valley where puddles of Carbon Dioxide form overnight while the air is still. These gas puddles can occur over puddles of water. When animals (such as antelopes) put their head down to the water to drink, they take a few whiffs of the gas and die. 

So far there are seven installments. You can find links to them here.

Global Warming: More Proof

Thursday, January 22nd, 2009

We already have data showing that the average global temperature has increased in the past 50 years, and that spring is arriving earlier. Now a new study by researchers at UC Berkeley and Harvard shows that all the seasons are arriving two days earlier. In non-tropical areas the hottest day of the year is coming nearly two days earlier, and the difference between summer and winter land temperatures has decreased. Winter temperatures have warmed more than those in summer—1.8 degrees Celsius (3.24 degrees Fahrenheit) and 1 degree C (1.8 degrees F) , respectively. 

Photosynthetic Machines

Wednesday, December 17th, 2008

In twenty years, according to Department of Energy Secretary nominee Steven Chu, artificial leaf-like membranes mimicking plant photosynthesis will be converting sunlight into liquid fuels. Right now, the transportation sector is almost entirely dependent on gasoline, diesel, and other petroleum-based fuels. In 2003 it accounted for about 27 percent of total U.S. greenhouse gas emissions.

Will Somebody Please Adopt This Tree?

Friday, December 12th, 2008

This year there seem to be more Fraser firs than ever for sale in my neighborhood, the Upper West Side of Manhattan. No big surprise. Woody plant expert Michael Dirr once called them the “Cadillac of Christmas Trees.” Fraser firs have a gorgeous pyramid shape and a profusion of soft, short needles arranged spirally around the branches. They also smell great. 

What is shocking is the stark contrast between the countless Fraser firs that line city streets, lending a festive air during the holidays, and the gray skeletons found in the tree’s native habitat. The species is endemic to the seven highest peaks in North Carolina, Tennessee, and Virginia; it is found nowhere else in the world. But in the past fifty years the number of mature Fraser firs on these mountains has declined by as much as 91 percent. The species is threatened with extinction in the wild largely because of an introduced insect, the balsam wooly adelgid, which first appeared in the southern Appalachians in 1957. The insect attacks by entering the trunk of a tree through fissures in its bark that develop as it ages; two to seven years later, the tree is dead.

Another threat to the Fraser fir: As temperatures rise due to global warming, it has nowhere to go. It can’t migrate upward to cooler, higher habitat because it already grows at high elevations on those seven mountains, in forests believed to be ice age relicts. When the last of the Pleistocene glaciers retreated north, Fraser fir was left stranded on these mountaintops, which have climates similar to those of Maine and Quebec. 

Someday it may be possible to see Fraser fir only on Christmas tree farms, or frigid Gotham streets.

The species is in the National Collection of Endangered Plants, under the auspices of the Center for Plant Conservation, a coalition of botanical gardens. But Fraser fir deserves to live wild and free, outside the cultivated confines of a farm, a garden collection, or a seed bank. For a number of years, the National Park Service reportedly tried to control the balsam wooly adelgid at Clingman’s Dome in Tennessee, using the only effective control known to date — coating each limb of each tree with a mild soap. But this proved too time consuming and costly and was given up.

Scientists and government officials have their hands full with invasive pests and imperiled plants, not to mention budget cuts and a host of other impediments. But citizens can fill the gap. Another endangered native conifer, the Florida torreya, has a group of activists, the Torreya Guardians, advocating and acting on its behalf. Friends of the Fraser fir anyone?

Great Green Wall

Wednesday, November 26th, 2008

It’s telling that while China’s first Great Wall was built to hold back warrior horsemen from Central Asia, its new Green Wall is designed to counteract human-caused climate change.

Fifty years of forest cutting have left few trees to block the ferocious sandstorms that have pushed the Gobi Desert southward, ever closer to Beijing. According to a new study, the Green Wall, a 70-year project to plant a 2,800-mile shelterbelt of trees, could lead to an increase in precipitation of up to 20 percent and decrease the temperature in the area. The project also will improve relative humidity and soil moisture, and reduce prevailing winds. It is expected to be an international model for dealing with hotter and drier conditions expected due to climate change.

Do Food Miles Matter?

Saturday, November 15th, 2008

A dissenting view. Crux of the argument:

In the United States, a 2007 analysis found that transporting food from producers to retailers accounted for only 4 percent of greenhouse emissions related to food. According to a 2000 study, agriculture was responsible for 7.7 percent of total U.S. greenhouse gas emissions. In that study, food transport accounted for 14 percent of the greenhouse gas emissions associated with agriculture, which means that food transport is responsible for about 1 percent of total U.S. greenhouse gas emissions.

The Carbon Footprint of Gourmet Dirt

Sunday, August 17th, 2008

An interesting story by Joel Achenbach in today’s Washington Post is, on its face, about how the price of potting soil has soared in the past year due to the high cost of the fossil fuels used to manufacture, package, and ship the stuff. But read between the lines and the story is really about how a once humble material has been transformed into an upmarket mixture of largely unnecessary components from across the continent and around the globe — and about how gardening (or at least the kind practiced by many Americans), an activity by definition assumed to be “green,” is anything but.

Bob LaGasse, who represents soil and mulch manufacturers as executive director of the Mulch and Soil Council, explains that consumers demand these high-priced designer mixtures, which a South Carolina-based producer calls “potting soil on steroids.” (Bob LaGasse also happens to be executive director of the Garden Writers Association, representing the people who recommend potting soils and other horticultural products to consumers.) 

It’s virtually impossible these days to find a bag of potting soil that isn’t loaded with synthetic fertilizer. Nitrogen fertilizer, as David Wolfe, professor of plant and soil ecology at Cornell University, has pointed out, is the typical gardener’s biggest contribution to global warming. The manufacture of synthetic fertilizer is extremely energy intensive. And the use of nitrogen fertilizers (whether synthetic or organic) releases nitrous oxide gas, which in Wolfe’s words “has 300 times more global warming potential per molecule than carbon dioxide.” Yet American gardeners have been hoodwinked into believing that applying fertilizer to their plants, whether in containers or in the ground, is as fundamental as brushing their teeth.

In addition to organic matter, from composted clam shells to pine bark, which could just as easily come from local sources but is often shipped from far away, the typical bag of potting soil is also likely to contain perlite transported from the Greek island of Milos and coconut coir from Vietnam, if not peat moss “vacuum-harvested” from Canadian bogs. Then the concoction is packaged in plastic bags, which are piled up and shrink-wrapped on wooden pallets for shipping to nurseries and superstores. In short, the amount of embodied energy and greenhouse gases associated with a bag of potting mix is mind boggling.

All for a few petunia plants likely to end up in a dump after the first frost.

California Plants and Climate Change — Even Worse Than we Thought?

Thursday, August 7th, 2008

KQED radio has produced an interesting follow-up to the recent Plos One paper predicting that climate change will have a dire impact on redwoods and other plants that are endemic to California, America’s biodiversity hotspot — plants found nowhere else in the world. (My blog on the paper is here.) A KQED reporter interviews the authors and finds they’re even more pessimistic than they were when they wrote the paper. One sobering prediction: Most of California’s endemic plants will die if global warming continues at its present pace. At the end of the century, redwoods could still be growing in California because adult trees are so long-lived. But since no seedlings will be able to survive, these adults will be the last redwoods on earth, a forest of the “living dead.”

On the KQED website you’ll also find an interesting slide show based on the radio interview.

Climate Roulette

Thursday, July 10th, 2008

How will America’s biodiversity hotspot — the state of California — fare as the climate changes? Not great, according to a new paper in the peer-reviewed online journal PLoS One. Its findings have implications for plant conservation that are guaranteed to raise a few eyebrows. 

The paper was the buzz among botanists at the annual conference of the American Public Garden Association in Pasadena a couple of weeks ago. California’s diverse and distinctive flora faces a potential “collapse,” David Ackerly, an ecologist at UC Berkeley and the senior author of the paper, told the LA Times. “As the climate changes, many of these plants will have no place to go.” 

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