(This is Part 25 of a series. Go back to Part 24.)
Another effect of climate change is that snow/ice masses are melting all over the earth. Icebergs the size of large cities are breaking off the gigantic glaciers in Antartica. The snow/ice cover on top of the Alps, the Himalayas, the Andes, the Sierras and so on are melting. The vast ice sheet across Greenland is melting more and more rapidly.
Well, so what? What difference does some melting snow and ice make?
First, those snow/ice masses which are in the mountains are "reservoirs in the sky". They store up and hold water during the winter, then release some of it in the spring and summer—filling the rivers during the growing season.
As these mountain reservoirs shrink, snow runs off during the winter, often creating floods. And during the summer, when water is needed the most, there is less snowmelt to fill the rivers. In fact, there is often draught instead. As mentioned before, floods and draught are often two sides of the same coin.
Second, snow and ice sheets all over the world reflect over 80% of the light and heat energy falling upon them. In contrast, land and water reflect only 20% and hold much more heat. This being so, as more and more of the snow/ice masses melt, less energy is reflected off the earth and more is held, warming the planet.
Note too that as more snow/ice masses melt the planet warms up more which causes more snow/ice masses to melt which warms up the planet even more and so on. This is a reinforcing feedback cycle which contributes to an acceleration of the global warming phenomenon.
In turn, the acceleration which is occurring could, in the future, take the planet past an ecological "tipping point"
of some kind, with unknown consequences.
We do know this. Land encroaching and global warming are putting increasing stress on the web of life. There have been five Great Extinctions in the earth's history; the last was the one 65 million years ago that killed off the dinosaurs.
Scientists are now referring to our time as the sixth Great Extinction, because so many species are dying off so fast. The rate of extinction is at least a thousand times greater than the background rate. Mammals, birds, amphibians and fish are all threatened.
The network of life depends upon diversity. Diversity is nature's way of protecting life against unknown hazards. As the diversity of life diminishes on planet earth, so too does the hold of life itself.
For example. there are only 5,000 tigers left on earth now, and scientists believe they will go extinct because there is no longer enough diversity in their gene pool to survive for more than a few decades. Ponder that for a moment: An earth with no tigers. If that isn't a sign, a symptom, a wake-up call, a canary in the mine...what is?
(This is the end of Part 25. Go to Part 26.)
—jim sloman, 10.21.04 for Oct 16
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