December 07, 2010
Plant Growth Negative Feedback On CO2 Warming

CO2 is food for plants and so higher atmospheric CO2 will boost plant growth.

GREENBELT, Md. -- A new NASA computer modeling effort has found that additional growth of plants and trees in a world with doubled atmospheric carbon dioxide levels would create a new negative feedback – a cooling effect – in the Earth's climate system that could work to reduce future global warming.

The cooling effect would be -0.3 degrees Celsius (C) (-0.5 Fahrenheit (F)) globally and -0.6 degrees C (-1.1 F) over land, compared to simulations where the feedback was not included, said Lahouari Bounoua, of Goddard Space Flight Center, Greenbelt, Md. Bounoua is lead author on a paper detailing the results that will be published Dec. 7 in the journal Geophysical Research Letters.

Without the negative feedback included, the model found a warming of 1.94 degrees C globally when carbon dioxide was doubled.

Note that in models of this sort there are many unknowns and probabilities. The warming from CO2 could be smaller or larger than this study used. The feedbacks from plants could be different for a number of reasons.

Plant growth causes both positive and negative feedbacks on temperature. This study finds the negative feedbacks will dominate.

An example of a positive feedback would be if warming temperatures caused forests to grow in the place of Arctic tundra. The darker surface of a forest canopy would absorb more solar radiation than the snowy tundra, which reflects more solar radiation. The greater absorption would amplify warming. The vegetative feedback modeled in this research, in which increased plant growth would exert a cooling effect, is an example of a negative feedback. The feedback quantified in this study is a result of an interaction between all these aspects: carbon dioxide enrichment, a warming and moistening climate, plants' more efficient use of water, down-regulation and the ability for leaf growth.

When CO2 is high plants do not have to open up their pores for as long to let in CO2. So they lose less water. Hence the comment about "plants' more efficient use of water". That means plants will evaporate less water into the atmosphere. It also means that plants will become less water-limited in their growth. Curiously, the lower water need should cause forests to expand into deserts. Though higher temperatures could cause droughts in some areas that cut plant levels. Hard to say how this all shakes out globally.

While I expect Peak Oil to happen fairly soon I am far less clear on Peak Natural Gas or Peak Coal. Some argue that we have far less coal left than commonly believed. But we do not know how coal production would respond to sustained higher prices. Maybe 90% of the extractable coal will be used by 2070 (PDF). Then again, maybe the amount of coal available would double in response to less than a doubling of coal prices.

Share |      Randall Parker, 2010 December 07 10:22 PM  Climate Feedbacks

Dan said at December 7, 2010 10:59 PM:

I find it bizarre that the response of vegetation to C02 concentration hasn't been better modeled previously. It would be nice if the source code to some of these models was posted online for proper review.

Peak oil is upon us, but I think natural gas won't peak for quite awhile ... and coal will never peak (just become uneconomical)


Jake said at December 7, 2010 11:21 PM:

Yet another revised model from the fantasyland called NASA. Won't those bozos ever give up. Global Warming is so 20th Century.

th said at December 8, 2010 5:07 AM:

Given nasa's growing tendency to lie, the recent arsenic bacteria hysteria has been exposed as such, muslims are feeling much better about themselves watching us western gullibles gushing over their daily barrage of nonsense.

Bruce said at December 8, 2010 11:33 AM:

Peak Oil ... 10 years from now perpetually.

"NORTH AMERICA: The New Energy Kingdom? “With rising production from shale fields, the U.S. surpassed Russia last year to become the world’s largest supplier of natural gas. Shale now accounts for 10 per cent of the country’s natural gas production – up from 2 per cent in 1990. Chesapeake’s production from its next Texas project, expected by the end of 2012, will by itself supply the energy equivalent of 500,000 barrels of oil a day. For new oil, the U.S. has the huge Green River play that overlaps Colorado and Utah, one of the largest shale oil fields in the world. The EIA reports that the country’s proven reserves of crude rose last year by 9 per cent to 22.3 billion barrels. . . . Within a decade or so, North America will almost certainly emerge as the world’s biggest supplier – and exporter – of reasonably cheap energy.”

Engineer-Poet said at December 8, 2010 2:59 PM:

Nah, peak oil was five years ago.

The US shale gas boom is coming from the thermally-matured source rocks which produced the previous US oil boom.  But we're extracting the gas at a much faster rate, and will exhaust its potential that much sooner.  It's time to go nuclear.

Phillep Harding said at December 8, 2010 4:52 PM:

The first "peak oil" I recall was forecast for 40 years ago. Pardon my lack of panic.

Expanding forest cover, should humans assist in reforesting some areas presently denuded of trees, would increase humidity at those locations and downwind. I would expect temperature swings to be moderated, no idea what would happen globally if reforestation was widespread.

Engineer-Poet said at December 8, 2010 5:40 PM:
The first "peak oil" I recall was forecast for 40 years ago.
You mean Hubbert projecting the peak for the USA?  He was right on target.
Pardon my lack of panic.
Panic helps nothing, but if you think petroleum is going to stay cheap and plentiful you're a fool.  Plan for expensive oil, and act like it matters.
BioBob said at December 8, 2010 6:12 PM:

I just love the tenth of a degree C accuracy outputs of these climate models. AGW scientists routinely "adjust" the raw temp data [which is 80% suspect anyway] by 20 times this purported level of accuracy. Who cares ? They can and DO manipulate the numbers however they please apparently without repercussion, either scientific or moral. Nothing they claim is worth the paper it is printed on or the electrons it consumes.

Hong said at December 8, 2010 6:41 PM:

So the skeptics may have partial vindication here in their argument that runaway temperature rises were unlikely. And that the tree ring data Michael Mann chose to hide because it didn't fit his alarmist narrative might've been more reliable then he or the believers wanted to admit.

Bruce said at December 8, 2010 7:47 PM:

EP: You are sad and bitter about the vast quantities of NG. How does feel to hitch your wagon to a losing philosophy?

"Assuming 1 per cent recovery,” the U.S. Geological Survey says, “these deposits [in U.S. territory] could meet the natural gas needs of the country (at current rates of consumption) for 100 years.”

2% recovery = 200 years ... etc.

Engineer-Poet said at December 9, 2010 8:14 AM:
EP: You are sad and bitter about the vast quantities of NG. How does feel to hitch your wagon to a losing philosophy?
The EIA and USGS have a history of predictions of abundance which fail spectacularly. 
"Assuming 1 per cent recovery,” the U.S. Geological Survey says, “these deposits [in U.S. territory] could meet the natural gas needs of the country (at current rates of consumption) for 100 years.”
The Globe and Mail article which is the source for your quote makes a number of errors (only one of which has a correction at the bottom).  Among other faults, it uncritically touts the Green River shale as a massive source of oil.  The Green River shale is a thermally immature rock containing kerogen, the precursor material of crude oil.  Despite efforts over more than 30 years, nobody has been able to produce oil from this rock at a profit.  Shell's on-again, off-again efforts at in-situ retorting were off again last I saw, not even getting a pilot test running.  Anyone relying on this to keep their Hummer running is in for a big disappointment at best.

Nature has buried lots of organic-laden shales deeply enough that earth's heat did all the thermal processing work for us.  It's quite a different matter to do it ourselves, and I don't expect the cost to improve much because the EROEI is an intractable matter of physics.  If you think oil shale is going to give cheap gas, first explain why it hasn't already.

2% recovery = 200 years ... etc.
Another fallacy of composition; that figure includes ocean-floor methane clathrates.  Clathrates are another thing like kerogen; they're there, but may be impossible to recover at a profit and will be expensive regardless.  At some price our current infrastructure becomes uncompetitive no matter how much fuel is available.

Actual US NG reserves of 284 trillion ft³ are about 13 years' supply at current consumption.  If you substitute NG for petroleum, you add another 35 quads of demand and reserves shrink to about 5 years.

If we finally developed fast-spectrum reactors, US uranium already in inventory could run the nation for several hundred years.  That's not from reserves in the ground, that's from DU tailings from enrichment sitting around in warehouses.

Bruce said at December 9, 2010 10:00 AM:

EP: Your lack of faith in Shale Oil mimics the exact same things you and Randall said about Shale NG.

90-116 years worth of NG WITHOUT HYDRATES factored in.

"•In its April 2009 report, "Modern Shale Gas Development in the United States: A Primer," the US Department of Energy stated that at the US natural gas production rates for 2007 of about 19.3 Tcf, the current recoverable resource estimate provides enough natural gas to supply the US for the next 90 years. Separate estimates of the shale gas resource extend this supply to 116 years. Production of shale gas is expected to increase from a 2007 US total of 1.4 Tcf to 4.8 Tcf in 2020. The DOE report states that shale gas production potential of 3 to 4 Tcf per year may be sustainable for decades."

Quit embarrasing yourself.

Bruce said at December 9, 2010 10:05 AM:

"The United States has abundant natural gas resources. The Energy Information Administration
estimates that the U.S. has more than 1,744 trillion cubic feet (tcf) of technically recoverable natural
gas, including 211 tcf of proved reserves (the discovered, economically recoverable fraction of the
original gas-in-place). Technically recoverable unconventional gas (shale gas, tight sands, and
coalbed methane) accounts for 60% of the onshore recoverable resource. At the U.S. production
rates for 2007, about 19.3 tcf, the current recoverable resource estimate provides enough natural
gas to supply the U.S. for the next 90 years. Separate estimates of the shale gas resource extend this
supply to 116 years."

morpheus said at December 10, 2010 2:04 PM:

good catch looks like the planet can balance itself without manbearpig gores

The Week
Dec 10, 2010

The irony: As negotiators from nearly 200 countries met in Cancun to strategize ways to keep the planet from getting hotter, the temperature in the seaside Mexican city plunged to a 100-year record low of 54° F.

Climate-change skeptics are gleefully calling Cancun’s weather the latest example of the “Gore Effect” — a plunge in temperature they say occurs wherever former Vice President Al Gore, now a Nobel Prize-winning environmental activist, makes a speech about the climate.

Although Gore is not scheduled to speak in Cancun, “it could be that the Gore Effect has announced his secret arrival,” jokes former NASA scientist Roy W. Spencer

Engineer-Poet said at December 14, 2010 5:28 AM:

Yeah, Bruce.  You just wait on those promises of oil from shale.  After all, 30+ years of negative results don't mean anything, do they?

th said at December 14, 2010 3:33 PM:

bruce said, "quit embarrassing yourself", Not possible, even if he started working on that now, stuff like this will come up to haunt the dumbass for at least another 20 years. I hear the hansen freak is on suicide watch....gore is too retarded to know what this means.

"According to scientists' models of Earth's orbit and orientation toward the Sun indicate that our world should be just beginning to enter a new period of cooling -- perhaps the next ice age."

Engineer-Poet said at December 15, 2010 1:35 AM:

That's production of crude oil.  It's not conversion of kerogen to syncrude by artificial thermal maturation of an immature source rock.

th said at December 17, 2010 2:35 PM:

Wrong slick, it's shale oil, oil from shale without the green river complications, something hubbert probably never heard of, I hear the marcellus has great potential in this area, the greenie kneejerks are the only thing standing the way.

Engineer-Poet said at December 18, 2010 3:54 PM:

"the green river complications" are the need to artifically heat and mature the immature material.  Not that repeating this to you will get through your belief that the difficulties are all from "greenie kneejerks" instead of inherent physio-chemical issues of the processing.

th said at December 19, 2010 4:52 PM:

jeezus, you are slow, eagle-ford is a shale formation that produces oil with the same relatively easy methods as shale gas, green river is like your texas wind dream, it ain't gonna happen. The greenjerks was in reference to paterson in NY banning fraccing in the marcellus, WWF, sierra club, etc. preaching to the choir up there. A good ad campaign always wins against rationality and no one ever accused the land of barney frank of being rational.

Engineer-Poet said at December 21, 2010 10:26 PM:

Perhaps you should tell all the people whose well water became undrinkable after the fraccing operations that they're victims of an ad campaign.

th said at December 29, 2010 4:45 PM:

here's a list of everyone so far from this fruitloop, perception isn't reality, a short pitiful list given the massive areas involved, new york, what a mess, all they want is a mosque shoved up their ass.

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