Polluting trees not such a far-fetched idea
By Ben Bova
Sunday, April 9, 2006
Good old Ronald Reagan.
Once derided as an aged, second-rate movie actor just pretending to be president, he's looking better with every passing year.
Early in his first term in the White House, for example, Reagan made a comment to the effect that trees produce air pollution. The news media howled at his gaffe.
But a few weeks ago, in a surprise that shocked many ecologists, a scientific study revealed that trees emit methane, a greenhouse gas that traps sunlight even more effectively than carbon dioxide does and helps to produce global warming.
Blame global warming on the trees?
Well, not entirely.
But trees and other green plants, including grasses, release more than 150 million metric tons of methane into the atmosphere every year, according to research done by Frank Keppler, a geophysicist at the Max Planck Institute for Nuclear Physics, in Heidelberg, Germany.
Atmospheric scientists were stunned by the German lab's announcement. They hadn't considered green plants as a source for methane. Methane, they thought, comes primarily from bacteria living in the guts of animals ranging from termites to cows.
Apparently, however, about 20 percent of all the methane put into the atmosphere comes from trees and other green plants.
This finding helps to explain the "signature" of methane that orbiting satellites have detected over tropical forests. Global warming is real: temperature measurements around the world show that our planet is heating up.
Last year was the warmest ever recorded. How much of the warming is due to natural processes, and how much due to human activities?
It seems no coincidence that the warming trend appears to follow closely the amount of greenhouse gases that human civilization pours into the atmosphere. These gases, such as carbon dioxide and methane, trap incoming solar radiation the way a greenhouse's windows do, raising the planet's temperature.
Scientists have long recognized that many plants produce volatile hydrocarbons that lead to haze and smog. That was the reason for Reagan's comment about trees and pollution.
But methane?
In the matter of pollution and global warming, trees and other green planets have always been considered the "good guys" because they take the greenhouse gas carbon dioxide out of the air and use it to produce carbohydrate sugars and starches through photosynthesis.
We human beings have taken the rap as the "bad guys" because we pump megatons of carbon dioxide into the air each year, mainly by burning fossil fuels such as coal, oil and natural gas.
International efforts to stem global warming, such as the ineffectual Kyoto Treaty, are based on the idea that humankind must reduce the amount of greenhouse gases we're emitting.
Now it turns out that those benevolent green plants aren't entirely benevolent: they produce lots of methane, which is a very efficient greenhouse gas.
The trees and other plants aren't the sole villains in the global warming arena, of course. Human actions still produce a lot more greenhouse gas than our green friends.
But we're not the only ones to blame. Score one for the Gipper.
• It's a thankless job, being the messenger who brings news that people don't want to hear. Just ask Naples resident Don Phillips.
An ardent recreational fisherman, Phillips started to get concerned several years ago about the declining stocks of fish in local waters. He spent three years researching the problem with fishery managers and biologists in Florida and elsewhere, around the country.
The result is his book, "Our Fragile Coastal Fisheries." It's been published by Trafford Publishing, an on-demand company based in Canada.
The subtitle of Phillips' book asks the question, "Can They (the coastal fisheries) Survive Man's Relentless Growth?"
The answer to that question, as I read the information in the book, is: probably not.
In page after page, in interview after interview, in charts of fish populations not only in Florida but around the country, Phillips shows clearly that our fisheries are in deep trouble. Overfishing is one part of the problem. Commercial fishermen usually have the attitude that there's an infinite supply of fish in the sea; we can take as much as we like, the fish population will replenish itself.
But just as human hunting had driven many land-dwelling animals close to extinction — think of the bald eagle and the bison, for example — overfishing is threatening to wipe out the very fish stocks that the commercial fishing industry depends upon.
Moreover, development along our shorelines is destroying the estuaries in which many fish species spawn, and in which their hatchlings spend their earliest months.
When concrete replaces wetlands, when runoff into the estuaries is thick with fertilizers and pesticides, we are destroying the nurseries where tomorrow's fish are hatched.
Phillips is no tree-hugging extremist. He's studied the situation carefully and delved into the actual, measurable statistics. From the Columbia Basin salmon on the West Coast to the familiar Florida grouper, fish stocks are declining so precipitously that many of the most popular species are now endangered.
Nor is this merely a Florida problem. It's global.
Decades of unrestricted fishing by huge oceanic factory ships have sent fisheries worldwide to the brink of collapse. The famous Grand Banks off Newfoundland, for example, have been closed to commercial fishing by the Canadian government. Marine biologists have urged closing of most of the fisheries around Europe.
If these fisheries do collapse, most of the species that we eat will become extinct. Fish were once cheap and plentiful; in many parts of the world, the poor depend on fish to sustain them. If the fisheries collapse, human starvation will be the result.
Here in the affluent United States, many types of once-inexpensive fish already cost more than steak in local retail stores.
Phillips is telling an important story, but most people don't want to hear it. And that's the worst part of the problem: You can't fix it if you won't admit it's broken.
To get a copy of "Our Fragile Coastal Fisheries," contact Don Phillips via e-mail at tropangler@cyberisle.com. Especially if you enjoy fishing, read this book. Naples resident Ben Bova is the author of more than 110 books. His latest novel is "Titan." Bova's Web site address is www.benbova.net.
© 2006 Naples Daily News and NDN Productions. Published in Naples, Florida, USA by the E.W. Scripps Co.
naplesnews.com |
