More Fragile than They Might Appear: The Sierras’ Warning of a Warming World

A twenty-two year USGS study of 21,000 trees in the Sierras has produced an unexpected result: The trees are dying. Not just one variety, but the Ponderosa Pines, the White Fir Conifers, the Red Fir, the Jeffrey Pines and the Subalpine are all dying of the thirst and the heat and the insect infestation that accompanies drought conditions.

“They’re more fragile than they might appear,” says Dr. Phillip van Mantgem, an ecologist with the U.S. Geological Survey and lead author of the report that suggests even the slightest change in climate can produce unexpected results in a delicate ecosystem. In this case, in addition to the millions of Southern California trees that have already died due to the Bark Beetle infestation, the Sierra range will be more vulnerable to fires as the dying trees become kindling while the air their leaves and pine needles once cooled grows warmer.

This symbiotic relationship is not isolated to the Sierras. The Mount Parnitha Forest, long known as the “lungs of Athens,” burned earlier this summer in a nine-day heat wave at 46 degrees Celsius (114.8 degrees Fahrenheit). Mount Parnitha had cooled the air as it traveled down to the city of four million. Now the forest is gone and the air is hot and polluted – even by Athens’ standard. While the temperature has not yet reached 114.8 degrees in the Southern California Mountains, the USGS report states that during the twenty-two year study the range warmed by 1.8 degrees Fahrenheit, which turned out to be enough to cause the precipitation to evaporate before it could be absorbed by the younger trees, their root systems too small to store enough water to endure the drought conditions, leading the report to conclude that the trees are “more fragile than they might appear.”

The same could be said of the Oxford river valleys that flooded so terribly this year, the glaciers of the mid-Alps which can no longer support their ski lodges, the elderly of Hungary who are receiving visits from a concerned government and all the cities in Turkey where they’ve instituted water rationing in response to drought.

“The world experienced a series of record-breaking weather events in early 2007, from flooding in Asia to heat waves in Europe and snowfall in South Africa, the United Nations weather agency said Tuesday.

The World Meteorological Organization said global land surface temperatures in January and April were likely the warmest since records began in 1880, at about 3 degrees Fahrenheit higher than average for those months.

There have also been severe monsoon floods across South Asia, abnormally heavy rains in northern Europe, China, Sudan, Mozambique and Uruguay, extreme heat waves in southeastern Europe and Russia, and unusual snowfall in South Africa and South America this year, the WMO said.”


In response, the UN has announced a new Climate Change web site: Gateway to the UN System's Work on Climate Change which will track the climate crisis across the globe. The site is worth a visit, as is this link to the World Meteorological Organization, the UN report about our warming world, the IPCC report on Climate Change and something everyone can do to reduce their carbon footprint.

The USGS report link with Sierra Forest images taken by the lead scientist.