Plants May Be Far Less Capable Of Absorbing Excess CO2 Than Thought

[hatrack]

Plants do much less than previously thought to soak up carbon dioxide, say Bruce Hungate of Northern Arizona University and Kees-Jan van Groenigen of the University of California Davis. Their paper, appearing in the Proceedings of the National Academy of Sciences, suggests that plants are limited in their capacity to clean up excess carbon dioxide in the atmosphere. And unfortunately, even their current abilities may be diminishing.

According to the paper, the limitation on carbon take-up stems from a dependence on nitrogen and other trace elements that are essential for photosynthesis; the process that removes carbon dioxide from the air and transfers it back into the ground. "Our paper shows that in order for soils to lock away more carbon as carbon dioxide rises, there has to be quite a bit of extra nitrogen available - far more than what is normally available in most ecosystems," explained Hungate.

It was previously thought that rising carbon dioxide levels would also speed up the process of nitrogen fixation, where plants "pump" nitrogen back into the soil. But this process can only increase if higher levels of other essential nutrients, such as potassium, phosphorus and molybdenum are available. "The discovery implies that future carbon storage by land ecosystems may be smaller than previously thought, and therefore not a very large part of a solution to global warming," Hungate lamented.

While plants may not save the planet, they still play an important role in reducing carbon dioxide levels. "We do know that CO2 in the atmosphere would be increasing faster were it not for current carbon storage in the oceans and on land," said Hungate. "But land ecosystems appear to have a limited and diminishing capacity to clean up excess carbon dioxide in the atmosphere. Reducing our reliance on fossil fuels is likely to be far more effective than expecting natural ecosystems to mop-up the extra CO2 in the atmosphere."

EDIT/END

MODS: Press release, given here in its entirety.

http://www.scienceagogo.com/news/20060311043102data_trunc_sys.shtml

[Triana]

1. That's absolutely true...

...I sometimes work around some environmental orgs and I can tell you this is exactly what their scientists and researchers say. You can't UNDO CO2 damage by planting more trees and plants. Doesn't work. The ONLY way to reduce CO2 from the atmosphere is to STOP PUTTING IT THERE. Furthermore, planting certain plants and trees in areas where they didn't grow naturally can further upset the ecosystem there, putting more moisture, etc. into the air.

You can't fool with Mother Nature.

[phantom power]

2. We're going to have to engineer the ecosystems...

if we want to play the biological sequestration game. Engineered soil bacteria for increased rate of nitrogen binding. Maybe soup up the carbon-uptake metabolism in the plants too. Somebody posted a recent result in that arena.

[NNadir]

3. Well that's good news.

I was worried about things getting over grown, even with all of our new biofuel industries cutting them up as fast as is possible.

[Peace Patriot]

4. Where do you feel better--in a forest, where the air is cool and sweet,

and the light reaches you in dappled splashes, and you are surrounded by green and multicolored growing things, or on a crowded freeway, caged in by concrete and steel, on a hot smoggy day?

End of story.

Green and wet are good for us. Driving around like bugs in steel exoskeletons, bumper to bumper with other insectoids, with nothing to look at but concrete "sound barriers" and garish billboards, and breathing toxic fumes, is a form of racial suicide. What's NOT good for us, is NOT good for other living things and for all life in our fragile blue bubble of a planetary environment.

The UC Davis science department is supported by Big Ag and Big Timber. They don't want to hear that we should be planting trees, not cutting down the last of earth's forests--80% of which have been severely damaged or destroyed in the last hundred years alone.

I certainly agree that we should stop polluting the atmosphere, and should NOT depend on reforestation to clean up our mess--for one thing because it isn't going to happen. We are destroying earth's forests at a truly alarming rate. And the greedbags who are doing it are NOT going to use any of THEIR profits, or permit themselves to be properly taxed for the common good, to pay for reforestation that keeps up with deforestation, with the starting line being, say, 1900 A.D. (Note: A tree farm is not a forest. It's a farm full of evenly spaced baby trees. True reforestation means leaving the forest alone for about 500 years, so that the volume of living tissue increases, the root and leaf systems can increase to stabilize water flow and prevent soil nutrient loss, and endangered birds, fish and other species can re-establish habitat and recover.)

But these kinds of scientists who focus in on one aspect of the situation, and toss items like this into the corporate newsstream to take the heat off the de-foresters and polluters, are not doing us or the planet any good. There is one such scientist they use in California deforestation permits (called "timber harvest plans") who is always quoted when the issue of salmon land-based spawning habitat comes up (the streams in the forests), and makes the case for "ocean currents" and "overfishing" to explain the grave declines in the salmon population, letting the timber corporations off the hook for pouring rivers of mud and toxic herbicides into the streams where the salmon go to spawn. Obviously, a species that is impacted by overfishing, and/or may be impacted by "ocean currents," will be less able to deal with the stress of mud and pesticides in their spawning habitat. But that overall cumulative effects issue is not what is intended. What is intended is merely having a glib answer--something that sounds good and is plausible--in order to permit more and more and more logging, for the profit of a few, in habitat where there used to be tens of thousands of salmon, and now there are ten, or none.

The matter of global warming is extremely complex, and cannot be reduced to one simple equation (trees as carbon sinks). Global warming is not just making crazy weather and affecting immediate environments like those of the polar regions. It is placing stresses on wildlife, on the oceans, on ocean fisheries, and other systems that are already under stress. For instance, bird and other species' migration patterns have been altered. What happens when a reduced population of birds, affected, say, by a longer flying time, arrives at the nesting site, and finds it paved over, or finds all its favorite trees or shrubs gone. Given the grave loss of biodiversity worldwide, we cannot look at this as a natural development, which nature will solve--i.e., some birds will adapt; they will survive and may repopulate, and the others won't--the pattern of evolution since time immemorial. We have altered things too much, in too many places. The World Wildlife Fund estimates 50 years to the death of the planet! That is, at current levels of consumption, pollution, deforestation and loss of habitat. 50 years!

Obviously, re-forestation and re-vegetation--and STOPPING the destruction of virgin habitat--are one part of the answer. We must address the WHOLE problem, not just the problems humans face of wild weather, or flooded coastal areas, or lack of fish. We must look at secondary impacts, like the one above--multiple impacts on the birds, in a quickly dying planetary ecosystem. Leaving THEIR little piece of habitat alone--not paving it over, not deforesting it-- will help them to survive the OTHER impacts they face, including those of global warming (changed weather, changed food supplies, change in predation patterns, etc.)

Plant away, I'd say. Almost any plant anywhere is better than no plant (with the exception of invasive species). And trees are the best plantings of all, since they quickly create cool, wet areas--and cool, wet and green are good. You don't need a scientist to tell you that. Go outside and FEEL!