In If loss of the rain forest would deplete oxygen, why didn’t deforestation of North America and Europe do so?
07-Oct-1994, posted on the Home Page, Cecil doesn’t mention re-planting trees. The big paper companies like St. Regis and Weyerhauser treat trees like any other crop, planting more as soon as they cut down a batch. Don’t the scientists who figured out global warming factor that into their equations? Or is it just more fun for them to get up on a soapbox and shout, “We’re all gonna die!”
P.S. Re global warming–I can remember when back in the 1970’s, they were confidently predicting another Ice Age. Make up your minds, people.
P.P.S. "Too much warming in too short a time and farming is disrupted, the oceans rise . . . " and the next thing you know, you’ve got Kevin Costner starring in Waterworld. Quick! Plant a tree!
It is true that deforestation is causing some grief, particularly in terms of the Greenhouse Effect. However, I feel that this can be easily overcome through one simple action - the legalisation of marijuana.
The reason I say this is because the Hemp plant is one of the best photosynthesisers in the plant kingdom - they grow fast and use a lot of CO2 for their growth process. If hemp plantations were set up, not necessarily for narcotic use, but for more utilitarian purposes such as paper and rope, we could cut down (pardon the pun) deforestation and Greenhouse gases.
The way it works in theory is this: Global warming heats up the planet. Polar ice caps melt due to increased temprature. All that ice melting absorbs heat energy. Temprature drops. VOILA! Ice age.
One thing that Cecil didn’t mention is that some environmentalists (perhaps only the extremists?) DO say that cutting down the rainforests would lower oxygen levels in the atmosphere. Anyone have any info on what % contribution to atmospheric oxygen the rainforests currently provide?
IANAS, and I don’t have any statistics to back this up but…I believe that landbased plants provide a very small percentage of the oxygen in the atmosphere. I think like 75% or something comes from algae and other water based plants.
I suspect Cecil ignored that part because it is irrelevant. Yes the logging industry does replant trees now. That has not always been the case. While currently tree growth in this country has increased in the last century (because of conservation efforts including the logging industry), there was a far larger deforestation in Europe and North America than has been replenished in this manner. So to say they replant now is just to say that the U.S. has stemmed the reduction of tree quantity to zero or small gains, but that does not address the centuries of reduction.
Second, while that applies to the U.S., the deforestation of the rainforests in South America and Central America are not being replenished. This is because reasons for clearing include growth for cities and human population, and land clearing and cheap (and short term) fertilization for farming. This is different than logging for paper and lumber, which have a vested interest in having new trees grown to harvest later.
As for scientists factoring it in their equations, they probably do. As mentioned above, the replanting is far smaller than the deforestation.
Yeah, I know it doesn’t relate to the rain forest deforestation, but I have heard it said (admittedly, by anti-Earth-Firster naysayers) that it doesn’t matter about the tropical rain forests, because thanks to Weyerhauser, et al, there are enough trees in North America to take care of the world’s air needs, and so global warming is all humbug, etc. Anybody else ever hear this?
One, when trees are cut down, it seems they are replaced by grasses-do grasses have more photosynthetic activity than trees? heck, it might be that grasses are BETTER than trees in converting CO2 to O2!! In addition, it sems that the Amazon basin WAS grassland/savannah as recently as 12,000 years ago! Who says forests are better than savannas-humans probably would not have evolved if the world was all forested!
Second: what happened to the American billionaire (DK Ludwig) who tried to make the amazon into a giand pulp wood farm? I heard he lost his shirt-I guess the equatorial rain forests aren’t good for much after all. Given the fact that nobody seems to be able to farm them, then they probably should be left alone. The Brazilians certainly should know by now that the whole idea of colonizing the Amazon basin is doomed to economic disaster!
As of December 1999, the plantation was up for sale. Asking price: $1.00. But there’s a catch–it comes with $354 million dollars in debt. Any Dopers out there interested?
What's going on is that we have two competing things going on--cooling of natural origin, and warming due to greenhouse gasses. Until recently, the graph has been dominated by the noise and no trend could be discerned--everyone was arguing from a theoretical standpoint. However, in recent years, the line has climbed out of the noise--there's a pretty clear warming trend.
Unfortunately, this won't help much. Sure, crops like hemp are *FAR* more effective at removing carbon from the atmosphere and converting it to organic material. However, that's not the whole picture. To do any good environmentally, the carbon must remain removed--and that's not going to happen much with hemp. Most of the material will be used, decay and release the carbon right back into the atmosphere.
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Quoting Nanook of the North Shore:**
The way it works in theory is this: Global warming heats up the planet. Polar ice caps melt due to increased temprature. All that ice melting absorbs heat energy. Temprature drops. VOILA! Ice age.
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Nope--melting doesn't actually lower the temperature under normal conditions. (It will if you take fresh-water ice and add salt, though.) Instead, the considerable heat required simply slows the melting.
I haven't heard exactly this, but I've heard similar assertions--never backed by any analysis, though. I don't believe it, though--*IF* it were correct, then the currently far higher level of vegetation would be converting CO2 to O2 far faster than other forces reversed the reaction--something that is obviously not happening.
There is some thinking that global warming may actually precipitate another ice age. Here’s a 2-year-old article from Atlantic Monthly on the possibility.
The basic idea is that our currently climate depends on certain ocean circulatory patterns and that a key to these is the North Atlantic Current. When it gets to the far north Atlantic, it is evaporated by cold winds from Canada, making it salty and thus heavier so it sinks. This also warms the air and keeps northern Europe more habitable than it would be otherwise. But it’s also a part of a worldwide salt circulation pattern.
If global warming melts Greenland ice and forms a large lake behind an ice dam, the dam breaking could release enough fresh water into the north Atlantic to disrupt the whole salt circulation system. This would reduce the flow of heat from the tropics towards the poles and flip the Earth into an ice age.
This is just a summary. There’s a lot more in the article.