Posts Tagged ‘climate change’

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. 

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.

The Purchasing Power of Coffee Hounds

Saturday, October 4th, 2008

Java lovers take note: For better or worse, our passion for espresso, latte, or plain old cups of morning joe has had a dramatic effect on landscapes around the world — today, coffee is grown in at least 16 of the world’s 34 biodiversity hotspots — not to mention the people whose livelihoods depend on the stuff. In an effort to boost production, growers have increased their use of pesticides and are relying less on shade trees, which offer habitat for birds and other environmental benefits. Given increasing evidence of the health benefits of coffee consumption, this trend is likely to intensify, despite the fact that these practices make the crop more vulnerable to erratic weather.

No, this isn’t a plea for coffee hounds to switch to tea or hot chocolate (the same trends have been detected among producers of these crops). But it is a reminder that we can help protect the land and its people in coffee-growing regions by buying shade-grown products. According to the latest evidence, in an article published in the October issue of BioScience, sustainable farming that employs shade trees may improve coffee crops’ resistance to the temperature and precipitation extremes that climate change is expected to trigger. You can find a pdf to the full article here

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.”