Humans' 10,000-Year Warming Habit

BBC ^ | 12-10-2003 | Richard Black

[-YYZ-]

Which keeps a larger amount of carbon locked up: an acre of forest or an acre of vegetable farm? Obviously the trees lock up more carbon than the plants that replaced them do. As long as the wood from those trees is kept intact, you're actually slightly ahead of the game. As soon as that wood decomposes, or is burned, you've released that carbon into the atmosphere. So yes, replacing woodlands with farms does put some carbon into the atmosphere, eventually. If you do slash and burn like in the Amazon, you immediately release the carbon into the atmosphere, and the land may be so poor when you're done farming it that it won't grow much of anything for a long, long time.

Of course, none of that really matters if global warming exists and is not caused by so-called greenhouse gasses.

[4mycountry]

Sounds like hot air to me.

[Bernard Marx]

I think it is still OK to say that human agriculture can have a greater impact than natural vegetation.

Possibly. The thing is, we don't really know. Ever-increasing human populations contribute humungous amounts of methane as well. How many "cattle" were there in a state of nature? Last I heard there are more trees in the U.S. now than when Columbus arrived in the New World, and forests are extending their ranges northward.

My criticism is based on the fact there are no hard data in the study. If you can quantify and actually compare Mammoth Herd X to Black Angus Herd Y, and so many million acres of Tempskya Fern in the Jurassic to an actual amount of present day sorghum (plus crop rotation cycles) then I might pay attention. But it's all Blue Sky academic posturing.

[F.J. Mitchell]

All speculation beyond the scope of one's knowledge, is pure BS, regardless of the number of diplomas that decorate the walls of the genius.

[from occupied ga]

this 10,000-year warming added almost a degree Celsius to the global average temperature.

It is all of the diesel tractors that were used in the paeolithic that started the problems. Once these tractors were converted to run on ethanol in the neolithic then global warming slowed

[Pan_Yans Wife]

Did you hear that in Australia, the farmers are now charged a methane tax, because of environmental impact? :)

[ancient_geezer]

Humans have been warming the Earth's climate for the last 10,000 years, US scientist William Ruddiman claims.

 

Figure 1-2 Climate of the last 2400 years

Hmmm! strange definition of warming trend by humans there. Looks like overall down to me.

Figure 1-3 Climate of the last 12,000 years

Ohh! I see, It must-a-been that jump in temperature just before agriculture set in from all them caveman hunter/gatherer campfires.

[Calvin Locke]

Don't forget Mars. Mars is warming too. Must be all those failed spacecraft that keep crashing (if they're lucky
enough to even reach the planet) on Mars. No other reason for it.

[Jackson Brown]

If you do slash and burn like in the Amazon, you immediately release the carbon into the atmosphere, and the land may be so poor when you're done farming it that it won't grow much of anything for a long, long time.

This is true if you just consider the "burn" part. However, it is also true that the rotting "material" on the Amazon's floor produces more CO2 than the Amazon's trees take in. This is more or less true for most old growth forests...and, NO, I'm not suggesting any actions here, including cutting down of old growth forests...just adding to the mix.

[Consort]

Weather is caused by stray lingering thoughts of dead humans. Everybody knows that.

[Jackson Brown]

And it does not alter the assertion that almost a further degree Celsius has been added over the last century alone, mainly through our dependence on fossil fuels.

This theory might not alter this conclusion, but the facts do. The short AND long term records show that warming came first and then the atmospheric CO2 build up FOLLOWED! Since warmer soil and water can retain less CO2, it is more logical to view warming as the cause of atmospheric CO2 and not visa versa...especially since that is what the most recent studies that address the cause and effects now show...but are ignored by the GW entrepreneurs!

[-YYZ-]

"This is true if you just consider the "burn" part. However, it is also true that the rotting "material" on the Amazon's floor produces more CO2 than the Amazon's trees take in."

I can't see how that is possible over the long term if the forest is fairly stable over a long term. Where does the rotting material come from, if not from the trees? If a tree dies and falls, it ends up rotting on the forest floor, but another tree will eventually fill that space and consume an equivalent amount of carbon from the air. Otherwise all the rotting material on the forest floor would eventually disappear.

However, that does mean that once mature, a forest like that is essentially neutral in terms of carbon inputs and outputs. The carbon is not being locked away, like in fossil fuels or the carbonates from sea creatures of all sizes that eventually become limestone. But it does keep a certain amount of carbon tied up, and that amount is larger than fields under cultivation would tie up.

[Old Professer]

This is typical of "scientists": when your argument proves unmarketable, change arguments.

[Mad Dawgg]

"6-8" of global warming expected here in Cleveland tonight."

I predict no matter what frigged-up science the global warming nuts use to try and prove their point the will ultimately fail because of Buffalo New York and Cleveland Ohio.

Anyone who has spent a winter in either place will never believe there is anything at all to the phenomenon known as Global Warming!!!

[Jackson Brown]

I writing this quickly, so if it not completely clear, or comprehensive...I apologize in advance.

There are a lot of recent studies that show this (the dead material emitting more CO2 than the trees take in). I can't lay my hands on them right now, but the explanation -- for rain forests like the Amazon -- is that 50% of the dry trunk of tree (these are often 100+ feet tall and quite big around) is carbon. However, in dense old growth forests, 90% of the CO2 breathing part of the tree (where photosynthesis takes place and it gives off Oxygen) is in the first 15-20 feet of the canopy -- when you get 50 feet down from the canopy, only 2% exists.

When those trees falls, they more likely to cause the trees near it spread out and not be replaced by a new one of the same type...What sun does reach the floor usually just supports small plants that use less CO2 and emit less O2.

That 100+ foot tree -- and ALL the debris that the trees sluff off -- then emits it's stored carbon as it rots -- especially in very wet rain forests during rainy weather.

The dead material that flows into the streams and rivers gives off CO2 at an even more rapid pace. (see BBC report below on the Amazon that gives a small bit of the details regarding this)

---

'No solution' found in more trees

Planting trees to curb the effects of global warming is unlikely to work.
A US-Brazilian team has found that some parts of the Amazon rain forest emit more carbon dioxide (CO2) than they absorb in very wet conditions.

Their report, published in the journal Science, says previous studies have almost certainly overestimated how much CO2 the Amazon can take in.

And their study is backed by other work which shows newly planted trees will not grow fast enough to mop up CO2.

The Science papers are pertinent because the idea of using forests to curb global warming forms a central plank of the Kyoto Protocol, which world governments will discuss next week in Milan.

The protocol allows countries to plant new trees and conserve old forests rather than cut the amount of greenhouse gases they produce.

[SNIP]

Saleska's study of old-growth Amazonian rainforest shows clearly that drought or other disturbances that kill trees can lead to higher levels of carbon dioxide release.

These increases in carbon loss occur during wet seasons when the dead wood breaks down, not during the dry season as has been generally found.

Rest at --
http://news.bbc.co.uk/1/hi/sci/tech/3246938.stm

[blam]

"This is true if you just consider the "burn" part. However, it is also true that the rotting "material" on the Amazon's floor produces more CO2 than the Amazon's trees take in. "

Read This article.

Rainforest Researchers Hit Paydirt (Farming In South America 11K Years Ago)

[Jackson Brown]

Absolutely --

The bulk soil on the "untouched" Amazon floor is extremely poor -- despite the rotting material that falls since -- for the most part -- it just rots but does not sink into the ground. Most washes into rivers and streams and does not replenish the soil. recent studies show that a GREAT deal of CO2 is given off by the rivers that run through the rain forests that causes the release of the stored CO2. I was aware of what you linked -- but thanks nonetheless!!!!

[Timocrat]

A US-Brazilian team has found that some parts of the Amazon rain forest emit more carbon dioxide (CO2) than they absorb in very wet conditions.

You mean Ronald Reagan was right.

[Jackson Brown]

You mean Ronald Reagan was right.

I'm not aware of what Reagan said, but a WHOLE lot of what people have been screaming about (that has become the basis for a lot of Kyoto) is extremely flawed -- even before Kyoto became THE issue.

OLD GROWTH FORESTS, especially rain forests, are at best CO2 neutral. They are great to have, but don't use them as the basis to prove anything about being the "planets lungs".

FAR More oxygen is given off from the plankton in the oceans than forests...period.

New growth forests -- if managed right (like those planted by lumber/paper companies) -- give off far more O2 than old growth.

[stylin19a]

Professor Ruddiman has now calculated that if the Earth had followed its natural cycle over the last 10,000 years, it should have got steadily colder.

He should have been around my house the time I told my wife "Those slacks make your butt look big"