Schwartz in the news again:
Stephen Schwartz of Brookhaven National Laboratory makes our weekly roundup again this week. This time, its for a comment/reply in the latest issue of Nature concerning a previously published Nature piece “Quantifying climate change — too rosy a picture?” by Schwartz et al. In the original piece, Schwartz and co-authors argue that the IPCC Fourth Assessment Report (AR4) presents an overly confident assessment of climate sensitivity and potential future climate change. In the response by Forster et al, a number of IPCC lead authors point out that the Schwartz et al critique ignores or misinterprets several key IPCC findings.
update: if you don’t have a subscription, the original Schwartz et al Nature article is available here and the recent comment/reply is available here
update #2: It has been pointed out to us that the commentary by Stephen Schwartz and co-authors was published on the Nature Reports Climate Change website, rather than in the print journal Nature.
Re:192: Jim says: “Again many thanks for the various comments. Fair enough, you all make some very valid points. However, my question has not yet been answered. So far as I can see it has been avoided. Given that we all agree that the sun affects climate, what is the precise physics of this process? How, in complete detail, does the sun affect climate?”
The source of the Sun’s energy as discovered by the late Hans Bethe is nuclear fusion, that is the fusing of hydrogen nucleii into helium in the Sun’s core.The temperature at the core is 15MK but still needs an assist from quantum tunneling to overcome the electrical repulsion of positively charged nucleii. The Sun releases this energy, emitting electromagnetic radiation over all spectrums,from radio waves to gamma rays, including light, and makes life possible on our home planet.
When the Earth goes through orbital changes in its eccentricity,and the angular change in its rotational axis(from 21.6 to 24.5) and the change in the time when the Earth is closest to the Sun,climate change takes place, that is affected by the Sun.
Jim Cripwell writes:
“How, in complete detail, does the sun affect climate?”
Short answer: slightly, over geologic time.
Long answer: complete details are not yet in. Check back later.
Even what’s known won’t fit into a blog post, Mr. Cripwell.
Here are 63 answers from pasting your question into Google (not Scholar). Many are high school physics coursework pages.
http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=GYF&q=%22How+does+the+sun+affect+climate%3F%22&btnG=Search
Some of these might be a good place for you to start. Remember, as Dano reminds us from time to time, there’s no “Wisdom” checkbox for Google searches. Beware the Larouche pages with the “neutron star” ideas, for example.
Jim, let me try to make it simple. The energy that drives climate is radiant energy that traverses interplanetary space as photons and is incident on Earth. That’s what the Sun does. Most of the other processes are insignificant–and that includes the supposed influence on GCR by the heliomagnetic field. That’s it, Jim. Radiant energy gets absorbed by gases, water and the land, and that’s what drives climate. This is not very complicated. There is no evasion. If you think there is, then you have not understood my answer.
re Jim Cripwell (192, et al) I’ll take the question seriously; it sounds like Sandbox 101 and that’s more my level than some of the other posters here. The Sun puts out radiant energy ala Planck. This radiant energy tools throughout the solar system. Some of it, reduced by 1/d2, runs into the earth. When averaged over the full spherical surface of the earth at any one instant, about 342 watts/m2 enters the earth system, about 107 watts (I’m omitting the m2 for convenience) gets reflected back out and is of no consequence, leaving 235watts entering the earth system, ~67watts absorbed by the atmosphere and 168watts by the terra firma. This absorption heats the absorber up, just like anything left in the Sun’s rays.
Now the Earth also emits its own Planck type radiation, which is based on the surface temperature of a body. This cools the Earth. The net incoming radiant energy has to balance the net outgoing radiation almost by definition. Otherwise the Earth would continue to heat up or cool down, one, for ever. If the Earth’s outgoing radiation from the surface exactly matched the solar incoming (235watts), Planck’s formula says the temperature of the terra firma would be about 30°C less than it actually is. But, the top of the atmosphere does emit about 235watts so the Earth system balances. But there is some “funny business” going on between the terra firma and the atmosphere. The surface is actually emitting more that the 235 watts — about 390watts, and is also losing heat to the atmosphere through evaporation and other thermals — about 100+watts. But it’s also reabsorbing a pile, about 324watts, of radiation from the atmosphere. All of this latter stuff being the so-called “greenhouse effect” and how all of this radiation effects our temperature and in turn the climate. (BTW, I don’t use “so-called” as a pejorative; there is an on-going debate if that is the proper term given the physics that goes on.)
That’s my Sandbox101 version. For truth in lending, I’m an AGW skeptic, but of some of the specifics, not the general process.
Re. energy efficient transportation
Why does it have to be a car?
Trains work. Buses work. Bicycles work. Shoe leather works. And, the last two have the added health benefit of exercise. Sometimes the solution is not technical, it is a change in behavior.
IPCC models under estimate the rate of climate change due to the nature of the concerns process (CLIMATE CHANGE: The Limits of Consensus, Oppenheimer et al., Science 14 September 2007: 1505-1506, DOI: 10.1126/science.1144831), and therefore, recent economic studies discount the cost of impacts from global warming far too much. We need to consider the cost of impacts occurring sooner, rather than later. We likely do not have the time to develop and mature elaborate new technologies.
I would bet that per capita bicycle use in the USA increases dramatically over the next 30 years. Other new transportation technologies will have popularity in the next 20 years. However, as the impacts of global warming accrue, the virtues of bicycles will win out.
JCH — type into Google: 300 bar = psi
-or- convert bar psi
————————
AGU: http://www.agu.org/pubs/crossref/2007/2007GL030426.shtml
amazing.
RE biofuels and global warming: Biofuel development is a good idea, but there are a lot of conditions to be met if you want to make carbon-neutral biofuels – first being that the agricultural energy and fertilizer inputs have to be fossil fuel free. Energy costs vary widely – a fact that all energy budget estimates I’ve seen fail to account for. In fact, energy budget estimates for biofuels are all completely unreliable. For one thing, an honest appraisal of the question would include a very wide range of ‘answers’. In any process A -> B -> C -> D -> E, there are many possible energy budget estimates. The total energy expended is a path-dependent question, not a ‘state function’. There is no ‘right answer’. Do you use coal to power distillation, and diesel to run the tractors? Or do you use solar-powered distillation and oxen? Or some other processes?
See also World Agriculture Faces Serious Decline from Global Warming. “World agriculture faces a serious decline within this century due to global warming unless emissions of carbon dioxide and other greenhouse gases are substantially reduced from their rising path, and developing countries will suffer much steeper declines than high-income countries…”
Flooding, drought and heat waves are among the main culprits, and eventually seawater intrusion into groundwater will cause additional problems.
Thus, it really doesn’t make any sense to promote biofuels as a solution to global warming. Biofuels can indeed replace a percentage of current fossil fuel use, but only if you can figure out how to run agriculture without fossil fuel inputs. This means major changes in industrial agricultural practices, such as: a complete end to export agriculture via ship and plane, no more production of nitrogen fertilizers via natural gas in the Haber process, electric tractors powered with compact efficient batteries (i.e. cell phone/laptop batteries) that are charged with solar and wind, and use of renewable energy to drive distillation in the case of ethanol production, or for a heat source in biodiesel synthesis. Fossil fuel-free agriculture is a big challenge all by itself.
Regarding energy storage: There are many ways to store solar- and wind-derived energy. The most convenient is to use high-density modern batteries (like the ones found in laptops). You can indeed run cars with such batteries – see Tesla Motors, for example – and the only downside is the time it takes to charge the batteries. Simple solutions include battery swapping stations in place of gas refueling stations. Hydrogen is just silly – convert the electricity to hydrogen (which is difficult to store) and then back to electricity onboard a car? Two stages are always less efficient than one – just use batteries.
The only solution to global warming, however, is to stop using fossil fuels. That creates a problem – what do we do for energy sources? The solution to that problem includes sunlight (solar PV and solar hot water), wind and photosynthesis (i.e. biofuels). Essentially, these are all ‘solar technologies’ – the only ones that aren’t are geothermal and nuclear, which have very limited long-term prospects as energy sources. Of course, these strategies will only replace part of the current global fossil fuel demand – meaning we need net energy conservation and an emphasis on highly efficient technology, as well as global population stabilization. There you go – problem solved – except for that additional unavoidable warming that is in the pipeline already.
Re #187: [Think about this. You are an engineer in GM. You want to do the right thing. You see all the latest technology from vendors always trying to get GM’s attention. You talk to a lot of folks. So you KNOW what is out there.]
We can look at that from another perspective, though. Consider what can be done – indeed, what companies like Honda & Toyota are doing – with currently available technology. Then we can look at what the US auto industry chooses to build, and spend large amounts of money advertising and selling. And we could also consider the fact that the automakers’ managements are apparently willing to go on record, in court, with claims that they can’t do significantly better than they are now.
US automakers probably aren’t buying up & concealing all sorts of revolutionary new technology, but neither are they being honest about what could do with what they do have.
Matt Said:
“Imagine 10 40 year old directors from GMs power train division approaching San Jose’s elite VC and Jobs and Spielberg and Hanks and saying “Listen, there is so much amazing technology out there that can make a car that runs for 200 miles on a D cell battery…we’d like you to do a first round of financing for $20M.” I can promise you those guys would get funding that afternoon simply based on their names and track record even if the investors didn’t understand how the physics worked out.”
The fallacy here is assuming that you could do much of anything in the automotive sector with $20 million. Capital intensive industries such as this (and petroleum, by the way) have a built-in obstacle to competition. GM, Ford and Chrysler developed this infrastructure at a time when there was virtually no foreign competition and when resources and labor (and especially healthcare) were relatively cheaper. This is why the big 3 persist in a model that cranks out SUVs nobody wants without 0% financing or cash-back rebates. Their loyalty is to their capital investment–to the point where they are willing to make seemingly suicidal business decisions just so they won’t have to retool. This is also why the oppose increased CAFE standards. Henry Ford’s “You can have any color you want as long as it’s black,” has been replaced by “You can have any fuel economy you want as long as it’s under 24 mpg.” So given this, I’m afraid I don’t have much doubt that the big 3 would squash any idea that challenged their hemhorraging business model.
Ike Solem(206) — Use biodiesel in tractors and other agricultural equipment. Use biomethane to produce the fertilizer. Biofuels are practical and billions of dollars are being invested in setting up to do so, world-wide.
However, here is the rub: A current estimate of energy from fossil fuels is 390 exajoules world-wide and presumably growing yearly. An achievable goal for bioenergy, with considerable investment, is 440 exajoules by 2050, when the world’s population will have grown and, on average, become more energy intensive, perhaps growing from the current 400–420 exajoules from all sources to, say, 800 exajoules. So bioenergy can only supply about 55% of the requirement. The rest, and hopefully more than that, has to come from solar, wind, geothermal, waves, etc.
I say more than that because it would be a very good idea to begin sequestering biocoal back into the ground in abondoned mines and carbon landfills. The schemes for sequestering carbon dioxide appear risky to me.
But if some form of sequestration is possible, then the anthropogenic carbon load goes down. Hence I would greatly appreciate some responses to my comment #11.
Am I the first here to google:
“Jim Cripwell” ?
re: #206 Ike
Fossil-free agriculture is challenge: we agree, and especially on the fertilizer. I like the idea of electric tractors, at least for some areas:
http://www.renewables.com/Permaculture/ElectricTractor.htm,
and the following is interesting, although the conomics & land use issues of going back to horses in general seem unlikely:
http://www.livepower.org/About/solar_horse.html
In particular, tractors are like most local-commuter cars, only better: they don’t go very far away, and they come back to the home/barn every day, and if they’re designed well, you can switch battery packs to get in a full days’ work [that’s crucial when you’re trying to do a harvest before it rains.]
However, I don’t think all farm vehicles and relevant trucking infrastructure fit that, even assuming sensible rationalization happens. I haven’t yet seen electric combines or trailer trucks or ships [although I have seen kites for helping ships]. But really, if any necessary medium/long distance trucking /shipping ends up with cellulosic ethanol or biodiesel, that seems OK. Given that farm machines can last a long time, getting them to use biodiesel, flex-fuel, etc is at least going in the right direction. [I think John Deere is doing some of this … what they build now is a far cry from the one I learned on a kid.]
Interesting article:
http://news.yahoo.com/s/ap/20070915/ap_on_re_eu/switzerland_weather_monks;_ylt=ArLpHJ2gw3nFh1a8z6jfOPpvaA8F
Kind of puts paid to the folks who argue the MWP was warmer than the present.
Catman306, When I google Jim, I don’t get much other than on needlepoint and confused posts on climate.
Jim, I think that the reason I find some of your posts frustrating is that while you admit you know little about science, you are completely convinced that scientists are wrong. And because you don’t know about science, you tend to fall prey to any wild idea whether it has any merit or not. Look, those of us who are scientists are happy to help out in assessing the things you come across, and can even help with ideas of how to tell the difference. However, just as you wouldn’t tell an electrician how to do his job, you should realize your limitations.
Re 206 – Ike Solem says in part:”….we need net energy conservation and an emphasis on highly efficient technology, as well as global population stabilization.”
What?! Didn’t you hear our all knowing,super patriot,the vice president call conservation a “personal virtue” and imply that it is otherwise useless?
Kidding aside, it looks like were going to have to make a “virtue” into a necessity. The conservtion and improved efficiency seem attainable, but as far as population control is concerned,I’d like to hear what kind of proposals are out there that will make people stop “doing it”, other than spaying and neutering.
Two promising technologies, practical use of nuclear fusion( other than bombs) and an economical way to separate H2 from it’s molecular bonds,especially H2O are too far over the horizon to help with global warming.
There’s no one magic bullet out there. It’s going to take a combination of non fossil alternatives, to break our fossil fuel addiction.
Jim Cripwell — At the top of the page there is a link entitled Start Here. I recommend you do so the find some of the reading resources yoou seem to desire. Then I do encourage you to read all of the AIP Discovery of Global Warming pages.
catman306,
Nope.
You might want to check two of my earlier posts and the rest of the following thread…
G8 summit declaration: #136, #149
At times he prefers to pretend as if he is entirely uninformed with regard to physics, other times he prefers to claim he is a physicist – which is closer to the truth, having graduated from “… Cavendish Laboratories Cambridge during WWII.” Apparently participated to some extent in the military experiments regarding infrared transmission in the atmosphere early on in his career, currently in Ottawa, Canada where oil sands promise to make some companies rich – and where someone with a backrground in spectral analysis might be in some demand. Quilting took on some importance to him with the loss of his wife. At present he is retired, but continues to make the rounds on the skeptic circuit and sometimes participates in the bigger internet debates.
>to google …
Nope. The postings could all be pretend-naive by a pro skeptic. We ordinary readers can’t see the IP address.
I figure it’s always possible a new youngster with the same name is asking honest questions — or the next reader along will be one and benefit from courtesy even if it’s misplaced at the moment.
Re 210 – It would seem that you are. I just did it and, oh lordy, how much time has been wasted on this guy who has no interest whatever in understanding the science. Thanks catman306 for such a simple and obvious reality check. When will we learn about these types??!
#210:
You didn’t first search within RC? [but you also need to do it with james].
There is some misinformation here that storing compressed air can be compared to storing electricity in a battery. This is NOT a valid analogy because electricity is stored as chemical energy at a constant voltage (say 14 volts is required to charge a battery in a reasonable period of time). Later it may be delivered to the system at say, 12 V.
A practical “engine” that uses compressed air may be able to handle the inlet air at say 20 bar (300 psi) which it would expand to 1 bar in the exhaust pipe (let’s ignore the cooling problem for now as the air gives up its internal energy to the piston).
Yet people are proposing air to be stored at 300 bar which requires (multi-stage) work of compression (let’s ignore removing the heat of compression for now).
So you’ve worked to compress air to 300 bar, but it can only be used at 20 bar, which implies an irreversible expansion across the tank valve. Poof, the sound you heard is 280 bar’s worth of “work of compression” being lost.
Natural gas vehicles do compress NG to over 200 bar, but NG contains a lot of chemical energy which air does not. Their range is typically 1/3 less than equivalent gas vehicles.
Of course, maybe you could build an engine that could handle the higher pressure (say 100 bar), but it would weigh 5 times as much.
Hardly a bargain.
Bottom line: air compression is not a viable means of storing energy in a vehicle, except that it possibly could be used for “air braking” in which air could temporarily be stored in a small cylinder at moderate pressure which would be injected later at this pressure into a cylinder at TDC upon acceleration.
Re #154 Tamino: I am impressed with how quickly you reply! I don’t agree with everything you say, and I feel a bit of a discussion on the nature of statistical inference coming on. However, before I do that I think I should follow your advice and analyze the monthly HadCRUT3 data. But you mention allowing for “red noise” – do you mean assuming that there is some serial correlation and then allowing for it? If so, it would be helpful if you could tell me what procedure you follow for this, as I could then do the same. If I agree with it :-)
This may take a little while – my wife keeps telling me I shouldn’t get obsessed with following all this climate stuff in my non-copious spare time.
Re #164 Chase: Thanks for the pointer to Tamino’s website – I guess I should look at that before replying to Tamino (#154)!
You say: Solar variability has been a negative forcing since approximately 1960, best estimate.
I don’t see how this squares with Lockwood & Frohlich, whose Figures 3 and 4 show two major sunspot peaks (after 11ish year cycle removed) in the 20th century, the last of them at 1986. Smoothed solar activity still has a way to fall before it reaches the levels before the 30s and 40s peak.
You say: Anyway, given natural variability due mostly to the lateral and vertical distribution of heat content in the oceans and the ocean currents, the people at Hadley are expecting next year to remain flat, but temperatures to start rising again after that with about half the years in the following decade to be as high or higher than 1998 or 2005. After that the global average temperature will typically exceed both years and continue to rise in the decades that follow.
So, apparently the Hadleyans have a good model for ocean temperatures. My question is, again, would they be so good as to publish results of models with this and that effect removed, so that the general populace can get an idea of the various contributions? I do see that this would be harder than it sounds, because of latency, but I would at least like to see some attempt at this. Specifically, if they expect flat temperatures for a couple of years before another increase, is it because of the solar cycle, or because of La Nina, or something else which might or might not be explicable?
Re #191 Levenson:
You say: “There’s nothing unknown about it! The Sun affects climate through the value of the total solar irradiance (TSI, the Solar constant), the amount of energy it puts out.”
As far as I can tell, the solar brigade believes in physics rather more subtle than that. They believe that the qualities of irradiance are important, such as wavelengths, solar particles, magnetic effects etc. Their point is that these things affect weather, which affects cloudiness, which affects albedo, which affects global temperatures. They don’t have a global circulation model for this, but they do have correlations with sunspot cycles. Alas we don’t have measurements of the TSI for more than about 30 years; if we did we could tell whether TSI is sufficient to explain solar-related climate change of the past millennium – but personally I doubt that it is, and I note that Lockwood & Frohlich were careful not to concentrate on TSI alone. This, I think, is what Cripwell in ##155, 166, 192 is asking about, and not getting any answers.
[[ Given that we all agree that the sun affects climate, what is the precise physics of this process? How, in complete detail, does the sun affect climate?]]
Things that don’t reflect or transmit all the light that falls on them absorb the rest, and by absorbing photons they heat up. The sun heats the ground, and to a lesser extent, the atmosphere. That is its major influence on climate.
The sun radiates about 3.8 x 10^26 watts of illumination altogether. At the Earth’s distance from the sun, that results in a “solar constant” of about 1366 watts per square meter (1367.6 is a frequently-quoted value, though probably too high).
The Earth is a sphere, and absorbs light over its whole surface area (4 pi R^2, where R is the Earth’s radius). But sunlight only falls on its cross-sectional area (pi R^2). The average sunlight falling on a given square meter of Earth, then, is about 342 watts per square meter.
Not all of this is absorbed. The Earth has a “bolometric Bond albedo” of 0.306 according to NASA, meaning it reflects away 30.6% of the light that falls on it. The flux actually absorbed, then, is about 237 watts per square meter.
For the Earth’s temperature to be neither rising nor falling, on average, the amount of energy the Earth radiates away must equal the amount coming in. The Earth, like the sun, radiates as the fourth power of its temperature. It radiates 237 watts per square meter if its temperature is about 254 degrees Kelvin (K). This is the Earth’s “effective temperature” (or equilibrium temperature, or emission temperature).
This can all be put together in an equation:
Te = (S (1 – A) / (4 sigma)) ^ 0.25
where Te is the effective temperature in K, S the solar constant in watts per square meter, and sigma the “Stefan-Boltzmann constant,” which has a value in the SI of 5.6704 x 10^-8 watts per square meter per kelvin to the fourth.
You’re probably way ahead of me by now in noting that water freezes at 273 K, so if the Earth’s temperature is 254 K, why isn’t the Earth frozen over? The answer is that the temperature at Earth’s surface doesn’t have to be the same as the effective temperature, and for almost any given planet will usually be higher. The Earth’s average temperature is about 288 K. The difference is caused by the atmosphere greenhouse effect — water vapor, carbon dioxide, and some other trace gases absorb infrared radiation from the ground, heat up, and give off infrared light, some of which goes back to the ground. You’ve got both sunshine and “atmosphere shine” warming the ground. An Earth without an atmosphere, and with the same reflectivity (not really very likely), really would be frozen over at 254 K, on average.
Variations in sunlight do affect the climate. They affect it most directly through the solar constant — less light, cooler Earth, more light, warmer Earth.
The way sunlight falls on the Earth, its distribution over the Earth’s surface, can be altered by the Earth changing its position or distance or angle of tilt. Long-term cycles exist in the Earth’s orbital eccentricity, axial tilt and precession, and these “Milankovic cycles” appear to be linked to the waxing and waning of Earth’s ice ages. That’s the other major way in which sunlight can be said to affect Earth’s climate.
For more on the subject, without getting too mathematical, I can highly recommend George S. Philander’s book, “Is the Temperature Rising?” (1998). If you don’t mind the math, John Houghton’s “The Physics of Atmospheres” (3rd ed. 2002) is very helpful.
John, again, I don’t find much, unless you are referring to Jim’s touting his experience in IR spectroscopy at Cavendish here and elsewhere. I do note that Jim has never told us what he did at Cavendish–just that he worked there. However, even in his posts on IR absorption spectra we see the same tendency to latch onto one single fact and draw conclusions without understanding the aggregate of the evidence or the work.
Thus, the fact that water vapor absorbs more IR than CO2 in the lower atmosphere means no other greenhouse gas can be important.
And the fact that there is a neutrino deficit (now understood in terms of neutrino oscillations, BTW) means the Sun must be a neutron star.
I do note that Jim does appear to have the “flexibility” of all the other denialists in that now that his pet theories about water vapor are in ashes, he has latched onto “the Sun”.
OT, but it looks like McIntyre and Watts have inadvertantly confirmed Hansen:
http://bigcitylib.blogspot.com/2007/09/deniers-rediscover-hockey-stick.html#links
John (211), I can’t get your first URL address to work….
ps to John (211) (assuming 1st post made it): there’s a comma after HTM that messes up your 1st URL address.
Jerry Toman Says:
16 September 2007 at 12:48 AM
There is some misinformation here that storing compressed air can be compared to storing electricity in a battery. This is NOT a valid analogy …
From what I’ve read, the extraordinarily high PSI talked about in the cars is for volume purposes, not power.
I’m thinking more in terms of a turbine spun generator for electric motors to run farm machinery.
See – owe to Rich (#221) wrote:
I said “solar variability” and that this was “best estimate.” If you are looking at sunspots, they have been more or less flat (other than the simple ten-year cyclical behavior) since about 1950 – and in decline since 1980 – when global temperature really began to take off.
Please see my comment from a while back:
Friday roundup, #64
See – owe to Rich (#221) wrote:
You could always ask.
Not much point in asking me for that analysis though – I am a philosophy major who currently does programming for a software that tracks the performance of cell phone networks. Might want to contact the people at Hadley MET.
David, regarding post #11:
“We suppose it is possible to safely and securely sequester about 14 billion tonnes of carbon per year, from biomass sources. About half of that counter-balances the annual addition to the atmosphere from fossil and deforestration sources.
(1) Is this the correct estimate?”
Well, that just seems like an incredible amount of carbon! You are talking about twice the total amount of fossil carbon that is consumed each year. I posted this earlier, but here it is again:
“Planting trees is certainly a good idea, but it won’t even come close to ‘offsetting’ coal emissions, let alone the all fossil fuel emissions, and here is why:
From eia.gov : “For example, coal with a carbon content of 78 percent and a heating value of 14,000 Btu per pound emits about 204.3 pounds of carbon dioxide per million Btu when completely burned.(5) Complete combustion of 1 short ton (2,000 pounds = 909 kg ) of this coal will generate about 5,720 pounds (= 2.86 short tons = 2600 kg) of carbon dioxide”
To convert CO2 mass to C mass, multiply by 0.25; 1000kg of CO2 = 250 kg of elemental carbon.
It’s generally assumed that about 1/2 the mass of a tree is elemental carbon. So, how long does it take for a tree to accumulate the equivalent of one ton’s worth of coal? Keep in mind that according to eia.gov, under “business-as-usual” scenarios, “World coal consumption is projected to increase from 5,440 million short tons in 2003 to 7,792 million short tons in 2015, at an average annual rate of 3.0 percent”.
Trees don’t grow that fast; I can’t seem to find a good number – perhaps one ton every 20 years? So, using this estimate, how many trees per year would you have to plant to absorb all the CO2 created by coal combustion?
5.4 billion tons coal= 15.4 billion tons of CO2 = 3.8 billion tons of carbon – which is about 1/2 of the 7.2 GtC produced by human beings every year.
If we divide that 3.8 billion tons of carbon by our ‘tree uptake estimate’ (1/20th ton/year) we get a very crude estimate of 77.2 billion trees per year… about 10 for every human on earth – and these trees will need to be watered, fertilized, and cared for to achieve that estimate of carbon fixation. That’s every year… and since coal use is increasing, that means more trees will have to be planted every year. If you want to account for ALL the fossil fuel emissions, DOUBLE that estimate. (*QUADRUPLE for your case).
Conclusion? Offsets are not feasible, and carbon trading will have little if any effect on atmospheric CO2 levels. We simply have to stop converting fossil fuels to atmospheric CO2, and use alternative energy sources.”
There really is no way around the basic fact that we need to stop burning fossil fuels if we want to stabilize or reduce atmospheric CO2. Politicians and the media seem unable to come to grips with this, despite all the talk about ‘fighting climate change’ and ‘promoting sustainability’.
PS to #229
When I wrote:
… I linked to the right page but the wrong comment. It should have been:
#64 on 15 July 2007 at 6:24 PM
https://www.realclimate.org/index.php?p=459#comment-37289
Re #212: [Bottom line: air compression is not a viable means of storing energy in a vehicle, except that it possibly could be used for “air braking”…]
In fact, UPS & others are working on a similar system for urban delivery vans, which need to make many starts & stops. The hydraulic (as it’s called, though I imagine the energy is stored in compressed gas) system seems to be more efficient than electric: though it doesn’t store as much energy as a hybrid’s batteries, there’s less loss in a cycle, and the system doesn’t degrade over many cycles, as batteries do. See here for more:
http://www.pressroom.ups.com/mediakits/factsheet/0,2305,1315,00.html
What does anyone have to say about this carbon sequestration venture? To me it sounds fancifal and since the oceans are warming more, CO2 is being released already at increased levels.
http://money.cnn.com/magazines/business2/business2_archive/2007/06/01/100050969/index.htm?postversion=2007060705
Question: One of the DOE’s Information papers says, “Radiative forcing is defined as a change in average net radiation at the boundary between troposphere and stratosphere (known as the tropopause).” Does anyone know why (or if) this is how forcing is defined? Is there any significance? I always (simply) thought forcing was just the net change in the energy/time/area entering the earth system — kinda anywhere…
Ike Solem(230) — I agree that carbon offsets are only a ‘feel good’, not a solution. However, there are at least two routes to permanent carbon sequestration:
(1) Produce biocoal and sequester it in abondoned mines and carbon landfills. Unfortunately, it is unlikely that enough biomass can be diverted to this endevor to do much good.
(2) Sequester carbon dioxide in deep saline formations or uneconomic coal seams. This will cost $$.
As for my question (1) in comment #11, I seem to have subsequently found the answer I was after. From the Broecker paper referenced in an earlier post, we currently add about 8 Gt per year to the active carbon cycle, so the concentration of carbon dioxide in the atmosphere increases about 2 ppm per year.
But the thrust of my questions in comment #11 have to do with the response of the climate system to decreasing the anthropogenic carbon load in the active carbon cycle. Suppose the 8 Gt per year is sequestered or fossil fuels are not used. Suppose it is possible in addition to sequester, permanently, 7 Gt per year. How does the climate respond?
Now I certainly presume it begins to cool, but I am sure that you have a better understanding than I of the sequence of events and I’d greatly appreciate you answering the remainder of the questions in comment #11.
This is not just idle curiosity. We know that during the Eemian, with a climate system in near equilibrium, the sea stand rose about 5 meters above that of today, and with a pulse of carbon dioxide lasting 300–600 years of about 290 ppm, up from about 270 ppm before and after. Unless it is possible to remove enough carbon, quickly, we’ll experience something similar, perhaps higher and faster. A catastrophy for those around to experience it…
#219 Jerry Toman
Good post! The same problem is true of methane as an automotive fuel. It takes almost as much energy to compress the gas into a usable form as is contained in the gas. But stationary engines or fertilizer manufacture (as some wise poster above has written) can use methane at its point of release from landfills. I hope that someday methane will become an important energy source in the north as the tundra melts and releases its potent greenhouse gas.
What you make of this methane irruption?
http://www.sciencedaily.com/releases/2007/09/070911092139.htm
re 230: Forest Guardians (in the offset business) say the average tree weighs less than a ton at maturity, which they take as 100 years, so has sequestered 1/2ton (300-350kg to use their exact calculus) of carbon over 100 years, though their math seems a bit funny in places.
[ http://fguardians.org/support_docs/document_carbon-calculation-methodology_2-07.pdf ]
Makes Ike’s point even more pronounced.
But something doesn’t seem right. One acre of corn (~10,000 plants) will sequester about 2500kg of carbon in one year, which is ~8 times what the average tree will sequester in 100 years. Seems funny. Any comments or insights?
Capturing and using escaping methane is bound to be an important new energy source to be added to the list. Perhaps someone will know how much more effective burning methane is when compared to other fuels toward the potential reduction of greenhouse gases. Do we gain anything by using as much of this naturally occurring greenhouse gas as we can? Methane’s principle drawback is that it must be used where it’s produced or transported by pipeline. But for methane capturing purposes, it is believed that the pipeline could be as economical as a heavy duty 3″ hose laid over the woods and melting tundra. Methane powered pumps would push the gas to some centralized electrical generation plant. On the quick it seems that this is a win for energy production and a win for green house warming reduction.
Even the large sheets of plastic that will catch the methane bubbles could be white and help reflect some incoming radiation.
http://en.wikipedia.org/wiki/Methane
Maybe this energy source could offset some fossil fuel greenhouse gas and be one of many different steps in the right direction that must be taken to keep our planet livable (for us). There’s no silver bullet, no single new technology that’s going put a stop to greenhouse warming. Greenhouse warming is a statistical entity, a construct. The remedy seems to involve, rather than a few super fixes, instead, billions of tiny fixes: each and everyone moving us some unmeasurable amount toward a more stable climate. That’s what we all want: a stable climate. Every smallest move away from fossil fuel can only help.
Doesn’t the mole of CO2 produced from burning one mole of methane mitigate the benefit ala greenhouse gases?
Rod B(238) — Different plants respond differently to envoronmental inputs. In particular, I suspect that the corn is putting on biomass in response to the heavy use of fertilizer.
J.C.H,
I don’t get it–you have to use electricity generated either from fossil fuel (or uranium) burned at a central power plant or from your own gas or diesel generator (much less efficient), to compress the air that later you’re going to use to generate electricity to power farm machinery? If this is mobile machinery, you have the same problem I discussed above with regards to powering cars or trucks on the highway. If it is stationary machinery, why not use the electricity directly, or if you have made it with diesel or gasoline, why not put this fuel directly in the fuel tank of your tractor? The second law says the more steps you use in transforming energy the greater the losses.
Look folks, these “home-remedies” developed to survive the coming energy shortages are not very likely to be successful, and even if they were, marginally, what would stop a hungry gang from coming in and taking what you had?
We need solutions in how we get and use energy that work for “most of us” or none of us are going to get through it. At the very least you should be working on solutions that work for whole villages (10,000 or more), not just for individuals.
For the reasons given above, I’m trying to gain support for the AVE which has that potential. Cheap electricity could even be used to generate road fuel from coal, if it came to that, by separating air cheaply (uses a lot of compression) to get the pure oxygen required and because it can use the heat wasted (50% of coal input energy) to recover 10-15% more of the original coal-energy input as by-product electricity in addition to the synfuel. Also, with cheap electricity available, carbon sequestration would become a much more feasible proposition than it is now.
With cheap electricity, homes could be heated using already commercial heat pumps instead of burning natural gas, which is also in short supply.
If you believe algae farming on desert land is the answer, you’re going to need a lot of cooling to prevent water from evaporating or the system from overheating, killing the beneficial algae doing the photosynthesis (5% bio-conversion from incident sunlight, 95% waste heat that must be “managed”). This cooling could be supplied with a propane-based refrigeration system run on electricity from the AVE.
In short, there are many substitutions that could be made using electricity, that would reduce or lessen the hardships that would be created from fossil fuel shortages.
My wish is for the people here to take a closer look at this technology and do what you can to assure it is developed to the point where we know for sure if it has potential or not. Please read the overview and business case at http://www.vortexengine.ca
For those who may be interested, a LOT OF MONEY could be made for those who see the potential and are willing to take the risk by ponying up what is needed for its development, which, by the way is at least a 100 times less than would be required for co2 sequestration technology development program.
Finally the FAQ section at the website can be very illuminating for those here who might be novices in atmospheric science.
AVE_fan
This one was estimated to weigh between 72 and 100 tons.
http://www.pleasantonweekly.com/morgue/2006/2006_01_13.atree13.shtml
David (241) says, “Rod B(238) — Different plants respond differently to envoronmental inputs. In particular, I suspect that the corn is putting on biomass in response to the heavy use of fertilizer.”
O.K., but a factor of 800 to 1 still sounds hard to believe.
Re. #235, you’re right that carbon offsetting isn’t the solution but it isn’t solely a feelgood either. A large proportion of offsetting money is used to fund projects such as increasing the energy efficiency of factories in developing countries; and even the offsetting money that is used to fund reforestation projects in tropical and subtropical regions is very helpful, if well managed, although not a solution on its own. Your criticism is valid for offsetting as a substitute for reducing one’s own emissions; but both have a place. A concerned citizen would sensibly try to cut their emissions by as much as they feel they reasonably can and offset the rest. As would a concerned government.
One hectare (2.5 acres) of Pinus radiata (Monterey pine) in a fifteen year old stand (in NZ) contains (for the purposes of carbon calcs) 112t of C. The trees are considered mature enough to harvest at 25-30 years, but will continue to grow (and sequester) well beyond that.
Different trees, different places = different strokes for different folks.
In my post about temperatures above, I should have said that the Earth’s average SURFACE temperature was 288 K. At a distance we would measure its temperature as averaging 254 K, since most of the radiation which gets out is from fairly high in the atmosphere.
[[You say: “There’s nothing unknown about it! The Sun affects climate through the value of the total solar irradiance (TSI, the Solar constant), the amount of energy it puts out.”
As far as I can tell, the solar brigade believes in physics rather more subtle than that.]]
Sure they do, because they know they can’t explain global warming on the basis of changes in TSI. But the sunspot cycle is highly correlated with TSI, and so are pretty much all the other variations they try to cite (e.g. galactic cosmic ray modulation). They are desperately looking for something other than TSI to explain global warming through solar influence, even though the only known climate correlations are to TSI or to things which correlate with TSI.
Since trees add an ever increasing volume of wood to their size each year of their life, why do those sites discuss maturity as some sort of limiting factor?
A growth ring is sort like a growth cone. A tree is like a stack of ice cream cones – one cone per year and each cone usually contains more wood than the last cone.
In the 459th year of that oak’s life, I would think it added a volume of wood that would dwarf the volume of wood it added in it’s 25th year.