dalem

The division of storms into 25 year, 50 year, and 100 year categories has been around long before the religion of human driven global warming. Read about the hurricane seasons of the 1930s, for instance.

-dale

Parihaka

Plants Exhale Methane, Contribute to Warming, Study Says
Brian Handwerk
for National Geographic News
January 11, 2006
Grasses and other green growth may produce 10 to 30 percent of Earth's annual methane output, a new study reports, making plants a surprising—and potentially significant—contributor to global warming.
Until the data were unveiled in this week's Nature, scientists had believed that plant-related methane formed only in oxygen-free environments, such as bogs.
But a team of European researchers identified a large range of plants that release methane under normal growing conditions. The gas also seeps from dead plant material.
David Lowe is a study co-author and an atmospheric chemist with the National Institute of Water and Atmospheric Research in Wellington, New Zealand.
According to Lowe, "We now have the specter that new forests might increase greenhouse warming through methane emissions rather than decrease it by being sinks for carbon dioxide."
"The identification of a new source should prompt a re-examination of the global methane budget."
Escaping Notice
The potentially enormous natural source of greenhouse gases had thus far escaped notice, which experts say is not surprising.
Thomas Roeckmann, a study co-author and atmospheric scientist with the Institute for Marine and Atmospheric Research in Utrecht, the Netherlands, said a very close look was needed to spot the emissions.
"The emissions per plant are rather small, and one has to look quite carefully to detect the increase above the high natural background of [methane]," he said. "So you would not find those emissions by chance."
Estimating the total global production of methane and other greenhouse gasses is far from an exact science, Lowe said.
"People who prepare the emission budgets use a bottom-up technology. Someone will make a measurement in a swamp somewhere and simply extrapolate that measurement upwards to represent all the world's swamps. They'll measure emissions from a cow or a sheep and extrapolate that upwards to include all of the world's animals.
"As you can imagine, there are huge errors. The science is so inexact that you could easily fit a new source like this into the estimates."
The new research may explain the large plumes of methane hovering over tropical forests that several satellites have spotted.
"That has been puzzling, and no one could explain it—but this provides an explanation," Lowe said. "It's [likely to be] the trees themselves that are producing that methane."
Unknown Contribution
Plants are just one of several natural sources of greenhouse gasses. Scientists believe that livestock like cattle and sheep may be responsible for some 20 percent of global methane emissions.
Just one full-grown dairy cow can emit some 100 to 130 gallons (400 to 500 liters) of methane each day as a product of digestive microbes breaking down their grassy diet.
Methane is considered a key greenhouse gas because it traps heat inside the Earth's atmosphere about 20 times more effectively than carbon dioxide.
Scientists have long known that anaerobic bacteria produce large levels of methane while breaking down plant material in bogs, such as Siberia's vast peatlands.
But the scope of production from oxygen-using live plants could be far higher—and have more dramatic results for the planet's climate.
Research suggests that rising temperatures could boost plants' methane production, which might help to retain heat and spark further temperature increases in a self-perpetuating cycle.
Just how big of a greenhouse cycle might be created?
"The size of the effect is difficult to quantify," Roeckmann, of the Dutch Institute for Marine and Atmospheric Research, said.
"It will depend on how sensitive the emissions are to various environmental parameters, [such as] temperature, increased carbon dioxide, and humidity."
"This is just a first research paper," Lowe added. "You really need others to get out there and confirm these measurements independently. You'll see lots of labs getting involved with this research."
Historical Context
The findings also may prompt scientists to revisit conclusions on historical climate change and its possible causes.
"We know that there have been periods of very rapid climate change, and ice cores have shown [corresponding] changes in levels of gases like carbon dioxide and methane," Lowe said.
"It has been thought that the land had reverted very rapidly to swamps, but it could be that in fact the forests played quite a major role in rapidly changing temperatures."
Roeckmann explained that global levels of plant and animal matter have also fluctuated during different historical eras.
"Our new results at least show the possibility that this could have a significant climate impact," he said.
"We postulate in our paper that the direct plant source made up roughly 50 percent of the global [methane production] in pre-industrial times."
"Thus [methane] emissions from plants represent a [newly discovered] process that can lead to warming and cooling of the Earth, certainly on glacial-interglacial timescales but, potentially even more important, on longer geological timescales.
"And of course this also affects the understanding of the current conditions."
Lowe notes that any reassessment of current climate change models could include some interesting political ramifications.
For example, the Kyoto protocol—an international treaty designed to try and curb climate change—requires complex accounting that holds countries to specified greenhouse gas emissions limits.
"Several countries are counting their forests as vegetative sinks for carbon dioxide," he said.
"But are you absorbing more carbon dioxide than you are [possibly] releasing methane? I suppose that the Kyoto protocol accountants are going to be working overtime trying to figure that one out."


http://news.nationalgeographic.com/n...t_methane.html

Anon

Further evidence that we just DO NOT know enough to be dicking around trying to 'fix' what's 'broken' in the environment.

We are such arrogant children...

Parihaka

Ahhh, but it's our arrogance that makes us great

Anon

...and dangerous.

FutureMD

The fact is, the world is getting warmer, and however many theories exist about the topic there is a simple one that most people can agree on: we just don't know why.

dalem

Sure we do - the median historical tempaerature of the planet is much higher than where it sits now. What more do you need to know?

-dale

gunnut

We're coming out of an Ice Age. Ever thought of that? The earth gets warmer everytime it comes out of an ice age. We're at the tail end of it.

Ever wondered why Greenland is called "Green"land? It should be "White"land.

It's called Greenland because it used to be green when the earth was warmer. Ask the Vikings. They settled there about a thousand years ago. Archeological evidences suggest they were able to raise lifestock there. You need pasture for farm animals. How do you do that on an icy waste land? You don't. Greenland was a good pasture land during the warm days one thousand years ago. Then a small ice age hit and turned the giant green grassland into an icy waste land. The Viking settlement perished.

Look it up. Earth is getting back to normal. Not burning up.


disclaimer: I assume Greenland is a direct translation of its Nordic name. Just in case if I make an ass of myself.

Anoop C

This thread is too long for me to read all the posts, so I'll just ask if anyone has heard this before:

One of the problems in assessing the extent and periodicity of global warming has been the (apparent) lack of temperature measurement stretching into the distant past.

I happened to talk to a person doing his Ph.D. in Geochemistry at the U of Chicago. He said that temperature can be quite accurately measured many tens of thousand years into the past by measuring the relative isotopic composition of oxygen in air bubbles trapped inside icebergs. He said that the data so obtained shows that the Earth is hotter now than at any time in the recorded past.

However, he admitted that the debate on global warming was too highly politicised to be much good. Another thing he mentioned is that the higher amount of water vapor in the atmosphere was trapping more heat than the CO2; but of course the higher amount of water vapor was a result of higher vapor pressure of water at higher temperature.

Apparently there is no danger of this cycle spiralling beyond control as had happened on Venus (?).
-----------------------------------------------------------------------------------------
My question is: is this common knowledge and has it been factored into the discussion here?

dalem

Your friend is running up against the wall of "the recorded past" in his claim.

The planet was much warmer than it is now over MOST of its known geologic history, i.e. the last 4 billion years. Periods of massive ice advance and coverage, such as we are still seeing in the last 100,000 years, are relatively rare. And gunnut is absolutely correct in pointing out that we are presently in a warming period during the current interglacial.

And the CO2/water vapor greenhouse cycle is well-understood. Venus is a little closer to the sun and therefore not a 100% mirror of the Earth's geologic history.

If you are truly interested there is a great deal of good discussion on this topic all through this sub-forum here. I lost one particular thread from last year where I went over some of the other big glacial advances in Earth's geologic past though. Bummer.

-dale

Horrido

It was called "Greenland" as a marketing strategy by Lief Eriksson. If he'd called it "White-tundra-permafrost-freeze-your-ass-off-and-starve-land," potential investors would hesitate to relocate there.

Haven't read this thread through because of all the posts and the meaningless, politicezed topic, but the bottom line is, temperatures have increased in direct correlation to increased pollutant levels since the start of the industrial revolution, after having been relatively stable before the industrial revolution. These are NOT left-wing whack-job professors supporting this, but cautious, conservative, highly educated and intelligent people that KNOW what they're doing and how to do it, despite the smear campaigns thrown against them by groups upset over what the research really means.

Human activity IS having a catastrophic impact on our ecosystems. This is in conjunction with a natural heating cycle, as well. The environment has been changing for all of civilization's history, and we're stupid to believe it's static. We aren't going to give up our oil, coal, finite-fossil-fuel-anything until it's run-out, the environment be damned in the face of our comfort and convenience of living. The ports of Alexandria and many other civilizations are deep underwater, now. LA, Manhatten, New Orleans, and most of Florida will most likely soon join them in the next two centuries.

Either way, I'm not worried about the planet. It has taken care of itself for over five billion years and through hundreds, if not thousands, of mass-extinctions from inumerable reasons. We are not a requirement for the global ecosystem's continued existence, if this experiment in intelligence fails and we check ourselves out, no big deal. Something will survive, evolve, and fill the gaps left by the extinction of others. I'm not planning on having kids, and I don't care if yours suffer. It's quite literally not my problem. It's just going to be a really cool shock when, natural or otherwise, things start going topsy-turvey, we start hitting mega-droubts in the west coast ENDING all agriculture and turning major rivers into mud-flats, or better yet, shocking the Atlantic oceanic conveyor belt to a dead stop and slinging into another major global ice age over a course of a few decades. It's all happened before, it WILL happen again, with or without human influence. Enjoy the current high, because when it ends, the party will be really, REALLY over.

__________________
The black flag is raised: Ban them all... Let the Admin sort them out.

I know I'm going to have the last word... I have powers of deletion and lock.

gunnut

It did work well though. The colony flourished for almost 400 years before it died out in the mid 15th century. There are archeological proof of the colonists diet consist largely of farm animals. Can't feed farm animals with ice. So they either imported grass, or the land provided grass.

astralis

in southern greenland, it is still warm for some agriculture- so yes, there is natural grass still there...

Horrido

I know they had grassland to work with, but it was also never really enough either volume-wise or nutritionally to support the herds. I wouldn't really say it worked well. They had to depend a lot on imports. I don't think the inhabitants of those colonies ever exceeded 50 or more individuals, and there's also some debate as to whether they were year-round settlements or summer fishing villages. A four-hundred-year time frame seems a bit long, too. My impression was a few decades. It's been 12-years since I studied the subject, so it's a bit fuzzy, and you could very well be spot-on right on all counts from more recent studies. Still, for Norwegians to pack-up and call it quits, it says a lot on how rough the realestate was. lol

dalem

Look, we KNOW that the ice sheets and glaciers have been advancing and retreating over the last few thousand years of recorded history, all over the world.

There's simply nothing to argue there.

-dale