240 comments on Fire or Ice? The role of peak fossil fuels in climate change scenarios
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240 comments on Fire or Ice? The role of peak fossil fuels in climate change scenarios
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Ugo, thanks for a nice overview.
Whilst I agree with this in part, I think it is incomplete. I will do a short post next week showing how coal fired combined heat and power district heating systems deliver 3* as much energy to society as coal fired power fitted with carbon capture. Improving energy efficiency is the way to go IMO - this extends the life of FF energy reserves whilst delivering sharply reduced CO2 emissions and lower energy prices in the near term.
The mindset that wants to deliver lower CO2 emissions has also given us bio-fuels and the fantastic notion of the hydrogen economy. IMO, the mantra of energy efficiency is the only route to go, delivering both greater energy security and reduced CO2 emissions in the near term. The focus on CO2 has led us to many energy intensive policies that are poorly suited to our energy declining future.
I believe you once said that "energy efficiency is the shortest route to Hell" - but that I beleive is coming from a rather different philosophical stand point - that would be fun to debate.
Euan, the sentence "energy efficiency is the straightest path to Hell" is not mine, it was said by James Kunstler, but I wholeheartedly agree with the concept. It is, indeed, a different philosophical standpoint which has to do with things such as the Jevons effect. I believe that most measures based on efficiency are ineffecitve. You can't believe how many politicians here in Italy conclude their speeches saying that such and such measure that they took resulted in so many tons of fuel saved and so many tons of CO2 not emitted. How can they say it? If you are more efficient, someone else will have more fuel available and that someone else will use it. For this reason, personally I have a drastic attitude: the only way to solve the crisis (be it climatic or geological - as you like) is to move as fast as possible to renewables (or maybe nuclear). That, as I say in the paper, cuts both ways.
Ugo, it looks like we have 3 choices:
1. Carry on as now and waste vast amounts of energy
2. Implement all energy efficiency measures available to us - keep this party going as long as possible
3. (2) + a system of energy rationing to counter Jevons
I strongly favour (3) employing tradeable energy quotas - that may make the poor and those who use little energy rich, whilst restricting the energy extravagance of the wealthy.
That I would favor, too (I mean, n. 3). There are alternatives, though. I would rather favor: 4. Use our resources to develop renewable energy and/or nuclear, so that we won't need fossil fuels any more.
I agree entirely Ugo, I meant to have a number 4. A much, much more vigorous drive towards viable alternatives is the best option. And that's where energy efficiency comes into its own - enabling activity at a much lower level of energy consumption produced from alternative sources.
How about a number 5. Cut the global population to a level that is sustainable? This would eliminate all of out current energy shortage, water shortage, land-water-air pollution problems?
That is going to happen anyway because of our gross population overshoot has been facilitated, and sustained (presently, by fossil fuels. Take that away and we are toast as a species.
Hopefully you are proposing following this option in the context of attempting to minimize our current exchange income in terms large scale exchange media like dollars and euros rather than maximizing it (consistent, of course, with the constraint of producing adequate levels of total income). If we do not find a way to substantially decouple the production of pychic income from the consumption of natural resources, then carbon free techno-fixes are not going to get us out of trouble.
If the alternatives to carbon based energy are more expensive than fossil fuels then even the OECD countries may have difficulty producing the constant increases in current exchange income in dollars, euros, etc. that are need for 'healthy' functioning of the financial system, let alone allowing countries like China and India to catch up to us as fast as possible. We need to reduce our total demand on the earth's resources and not just to reduce carbon emissions.
1. Carry on as now and waste vast amounts of energy
2. Implement all energy efficiency measures available to us - keep this party going as long as possible
3. (2) + a system of energy rationing to counter Jevons
The Kyoto treaty and others set to emerge work to counter (1) and strive to implement measures that result in (3) without specifically printing rationing coupons.
there are several phenomena that the climate models don't consider and that could make warming much more serious than currently believed. Among these, the saturation of the CO2 sinks, the positive feedback of the methane hydrates and those of the ice/albedo system. We just don't know enough to be able to say whether depletion is enough to "save" us from global warming.
This is a crucial point that is too often glossed over when peak fossil fuels are discussed wrt climate models. What I haven't seen mentioned are the results of 600 ppm from anthropogenic emissions mated with other positive feedbacks, such as;
Amazon's 2005 drought created huge CO2 emissions
Increasing temperatures drive up humidity, causing more warming
Methane releases accelerate as Arctic thaws
While we might not reach 1000ppm based on anthropogenic emissions alone, positive feedbacks will take us far above the GHG levels envisioned by those focused only on emissions reductions from peak fossil fuels.
Nobel Scientist: "Long before we run out of oil, we will run out of atmosphere"
This is important to point out since all global warming event of the past where natural we know that once a warming even is initiated it tends to continue. Most everything I've seen on the issue cannot assign the total C02 levels to a single source for the most part. Only the snowball earth final warming trend seems to be causes by volcanic C02 build up with a effectively shut down ecosystem.
http://en.wikipedia.org/wiki/Snowball_Earth
In general it seems that as a planet warms organic carbon is converted to C02 and methane is released as above. Thus the warmer the climate the lower the carbon content of the soils. Also of course plan respiration plays a large and generally unkown role. Natural fire events probably expand as the climate changes etc.
If you read everything about global warming then hopefully you will come to the same conclusion I have that anthropogenic warming is simply the accelerant that started a fire its no longer the driving force.
I think only one aspect of human pollution is still playing a big role and thats sulfur dioxide and particulate levels in the atmosphere from coal. This is a guess on my part but we saw the dust bowl develop during the Great Depression. My opinion was that this dramatic climate change was linked to a sudden drop in the amount of coal burned as the great depression hit. I think we will see a similar situation develop as the world industry slows. So I'd not be surprised to see a similar set of extreme climate events occur over the next several years. Given that the major sources are more widespread and China is playing a big role it may be different but I expect a climatic shock from a rapid drop in particulate and sulfur pollutants to play a role.
Later on if we see a sharp increase in oil prices and a real drop in driving because of the cost of gasoline we should see a second wave of climate change as local smog levels drop. Overall given that the result is more solar radiation hitting the ground one can expect that we would see warmer drier soils develop with higher moisture content in the atmosphere. Water is a potent green house gas. This leads to stronger winds which result in even more drying and more water in the atmosphere.
So in my opinion deep recessions/depression cause a sort of mini runaway greenhouse event based on shifts in the water vapor cycle and drying soils. This is driven by loss of smog.
from wiki: "The ratio of the increase in atmospheric CO2 to emitted CO2 is known as the airborne fraction (Keeling et al., 1995); this varies for short-term averages but is typically about 45%"
A large fraction of the CO2 which we emit is being absorbed by the world (mostly the ocean, but we don't know where it is all going) if any secondary feedback mechanisms begin to kick in, or these carbon sinks stop "sinking" as they saturate, then the effect that we have on the world could suddenly spike. Fortunately neither of these events has happened yet.
Unfortunately, there are signs that this may not continue much longer - warm oceans don't store CO2 as well, and acidified oceans cause a whole other set of problems. Climate related changes such as melting of permafrost / changing of style of vegetation cover can both potentially cause large emissions in CO2 (warming is unlikely to create more rainforest in the short term, perhaps long term after new rainfall patterns have been established).
I don't think that there is enough oil/gas around to permanently stuff this world up, but if we attempt to replace oil with coal, unless reserves are drastically optimistic, then there is more than enough coal around to cause significant problems.
I agree (not necessarily about the Dust Bowl). I expect to see a spike in temperatures over the next few years, as manufacturing declines and the resulting smog levels drop. We've already seen how particulate matter caused 'global coolong' in the mid century (as soon as we cleaned up the smog, AGCC resumed right where it had left off). Reduced smog levels letting in extra warming is one of those unintended consequences we hear about all the time.
I'm not sure what options there are to counteract this. There have been suggestions of the pragmatic (spew inert particulates into the air, long-term consequences unknown) to the ludicrous (massive orbital solar blinds). Perhaps we could simply require everyone to paint their rooves a light colour, to reflect the heat as we reduce particulate emissions.
The 9/11 effect when airplanes where grounded supports that this will be and issue. And as Andrew noted above our carbon sinks my be getting full.
This article is extreme and I don't necessarily agree with its conclusions but it seems to have a lot of info.
http://www.alternet.org/environment/32903
I used Dust Bowl as and example no telling what will really happen since the pollution patterns are different now.
The key point is that most of the evidence indicates that current C02 levels are sufficient to put the earth on a warming trend as has occurred naturally in the past. In fact they are probably a lot higher than levels that actually triggered a warming cycle in the past.
This suggests that natural feedback loops are already running and its doubtful we can stop the warming the only issue is how high will it go ? Probably continued use of fossil fuels at this point makes the eventual peak temperatures exponentially worse as trends are accelerated and loops run faster then they ever have in the past. Not only have we probably triggered a major warming trend but we probably are supercharging it.
This is where thoughts about local climate issues i.e global dimming because of pollution are important. I suspect we have a lot of micro feedback loops we triggered methane release etc etc that will cause a lot higher temperatures and faster warming then the global models indicate. I don't think they really model this sort of spreading micro climate change.
Think of it like a lot of isolated bacteria growing exponentially in their local environments then covering the whole area. Or think about a large glass window and shoot small pellets randomly at the window. Each pellet leaves only a small crack but even with a random pattern the entire window is soon shattered.
Our climate models can't really model this sort of concept its outside the scope but it does suggest that if this is right then the models are off by several orders of magnitude in their results both in time and in extremes.
The recent changes in arctic ice cover which are from a similar concept un-modeled cracking and erosion of the ice is a huge factor its effectively the same as the pellet idea and it seems to have result in a order of magnitude faster decline. So a high end projection would basically take our current climate models and multiply the temperature changes by ten and dived the time intervals by 10.
I really think that by doing this you get something thats within a order of magnitude of what will really happen. It may be twice as fast or extreme as what really happens but its much closer I suspect than our current models. Thus something forecast to happen in 100 years probably will occur within 10 or 20 years.
Before mankind forest fires probably played the role of providing global dimming early in a warming cycle only to have even faster warming once they ended.
Eventually as far as I can tell the cycle ends with large deserts on the continents and wind blowing dust into the ociean causing alagae blooms and plankton blooms eventually resulting in large oil deposits.
We have this right now with the Sahara for example so think of most of the world looking like the Sahara for say up to 1 million years before the system finally cools.
"The key point is that most of the evidence indicates that current C02 levels are sufficient to put the earth on a warming trend as has occurred naturally in the past".
We have been in the longest interglacial period for long time. IMO this must make us vulnerable to runaway warming and biospheric dystrophy.
Without arguing about anything else, it's very well established that the Dust Bowl was caused:
a) By *really* bad farming and ranching practices [speaking as an old farmboy, who grew up on a 100-year-old farm that still had topsoil]
b) And the inevitable drought episode.
The Wikipedia entry on Dust Bowl is OK.
One of the strongest predictions of climate models is that warming temperatures induce changes to Hadley Cell circulation, one of whose effects is long-term drought in the US Southwest.
What caused the drought ?
What caused the Hadley Cell circulation to change ?
Global dimming can work in reverse as industrial output slows.
I think its interesting actually that the heat island effect of cities is well known yet how a city effects the regional then lager climate patters is barely studied. Obviously how the soil is tilled and when it is tilled changes the moisture content of the soils. And obviously changes in coal burning change the amount of particulate matter in the air but the combination of the two or even both individually are not well studied at the climate level.
Another example I'm interested in moving to Oregon a lot of the cities now have flooding problems I found it interesting that houses that had been built 50-100 years ago now where being flooded obviously the flood peaks had probably increased. A suspicious cause is of course removal of the forest cover. Although this obvious link is actually debated. However moving outward increased erosion is so obvious that its accepted by all this dumps more sediments into the streams and thence into the ocean which in turn acts to increase algae blooms helped along of course with our fertilizers. These blooms eventually cause the dead zone ocean conditions as the material rots. This may withdraw C02 and it might add methane who knows I've not found any studies. But my point is that local changes can eventually cause larger regional changes. How these are linked into our larger regional climate systems seems to be a real blank spot.
In general the interest focuses eventually on water vapor the forgotten greenhouse gas.
http://www.waterencyclopedia.com/Ge-Hy/Global-Warming-and-the-Hydrologic...
http://lwf.ncdc.noaa.gov/oa/climate/gases.html#wv
Sorry for such a large quote but I got the impression from your response that you felt that you understood the cause from a wiki entry on the dust bowl.
I'd suggest its more complex and that we don't really understand what we have done. The combination of particulate and sulfur dioxide pollution from industrialization and various farming practices regardless of how well they control erosion since its soil moisture thats the issue do influence the local water vapor cycles and thence the global climate. My opinion is we will soon learn that C02 is really only a cycle initiator and that changes in water vapor dominate the climate cycle.
I didn't learn this from a Wiki entry, that was just a convenient pointer.
My father had a B.S. in Agronomy.
I grew up on a farm that had been in the family for 100 years. Farm kids learn about groundcover, crop rotation, contour plowing, before they're 10.
In any case, even without that, it was certainly covered in AP American History, in my Pennsylvania high school, circa 1963. These days, many schools teach this history in middle school. IOf course, *everybody* could be wrong...
Here's a map of Dust Bowl area. Here's a map of *current* coal plants. I don't have a map handy for 1930, but the population & industry was more concentrated in the NorthEast than now.
The sulfate/acid rain issue was primarily in the NorthEast, where the heavy industry was concentrated. When I was growing up near Pittsburgh, PA, in the 1950s, the pollutions was awful if you went downtown ... i.e., I'm quite familiar with particulate matter in the air, because I could see it as I drove 20 miles South into Pittsburgh.
The Dust Bowl didn't have that kind and density of industry there or upwind.
People certainly do study UHI & related effects on local climate.
See Mark Jacobson at Stanford.
I'm not sure why water vapor is a forgotten GHG. Climate scientists I talk to know about it. So does the IPCC.
There's always more to know, but one more time:
1) The usual oscillations cause periodic droughts, especially in the US Southwest.
2) If you farm and ranch in *really dumb* ways in such an area, sooner or later it catches up with you. The US Government spent a lot of effort to change the practices.
What Will Stewart neglects to mention is that a lot of this permafrost has already melted at least once since the last ice age during the holocene optimum and that methane has a far shorter residency time in the atmosphere than CO2.
1. The fact that it has melted before has little bearing on the amount of buried peat that will outgas its carbon in the form of methane.
2. The shorter residency time is more than outweighed by the fact that methane as a greenhouse gas is more than 25 times more potent than C02.
1. If catastrophic warming is supposed to be the outcome of the melting of this permafrost why did the Holocene Optimum come to an end? Bear in mind this peat built up primarily in past interglacials rather than in the current one.
2. The shorter residency time thanks to the reactivity of OH radicals in the troposphere helps to prevent a buildup over time given the graphs clearly indicate that the permafrost in question won't all melt at once, which leads back to point 1. Methane may be 25 times more potent but there is currently only about 1.7 ppm of it in the atmosphere compared to about 390 ppm for CO2.
The short residence time for CH4 is important and means it can't really be thought of in the same way as CO2. We think about CO2 in terms of reservoirs, with carbon moving between ground, atmosphere and ocean reservoirs. CO2 can 'build up' in the atmosphere reservoir. This is not the case for CH4. Over all but the shortest timescales the atmospheric CH4 concentration is, to a first approximation, directly proportional to the rate of emission. It's not critical to consider the CH4 reservoir; however the total amount of carbon in the CH4 is still important as CO2 results from the reaction with OH.
Re 1,
Why doesn't water vapour feedback lead to a hothouse or snowball earth? It acts continually amplifying both warming and cooling excursions, but it hits limits. It all depends on the circumstances.
Restricting considerations to the Arctic region: Even if current conditions are not yet out of the Holocene, with a further climb to 500-600ppm, also considering the reduction in "global dimming" as cited in the Zecca paper. The Arctic will very likely be in unknown territory later this century.
So it is quite likely that we will see significant addition to our emissions from the Arctic. There is a risk this addition could be substantial.
Re 2,
The 25 times potency figure is based on a 100 year timeframe precisely because of the action of OH radicals. On a sub-decadal basis the figure is nearer 70 (72 IIRC). The key factor here is the size and duration of a CH4 emissions pulse, large and fast will extend atmospheric lifetime, hence raising potency above 25.
The current increase in CH4 is not due to methane release from clathrates or permafrost melt. However Semilitov/Shakhova (1) and the International Siberian Shelf expedition team have already noted significant recent localised CH4 outgasssing from marine CH4 clathrates that is greater than in previous studies. Their work suggests the process is starting: e.g. "we consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. That may cause ~12-times increase of modern atmospheric methane burden with consequent catastrophic greenhouse warming."
David Archer notes (2) in the abstract that "any possible methane release will take place over time scales of millennia." And that the most important impact of CH4 is in it's final form - as reduced to CO2 by OH radicals and oxidation. However Archer states in the body of the paper that "The rate and extent to which methane carbon can escape the sediment column in response to warming is.. ..very difficult to constrain at present."
Apropo of which; it is worth noting that the source of the 50 Gt of methane cited by Shakhova(1) as being "highly possible for abrupt release at any time" is that proportion in proximity to vertical disturbances in the sedimentary column. These vertical disturbances can allow ocean warming to penetrate more rapidly than the layer-to-layer warming one might typically expect.
1. "Anomalies of methane in the atmosphere over the East Siberian shelf: Is there any sign of methane leakage from shallow shelf hydrates?"
http://www.cosis.net/abstracts/EGU2008/01526/EGU2008-A-01526.pdf
2. "Methane hydrate stability and anthropogenic climate change" David Archer, http://geosci.uchicago.edu/~archer/reprints/archer.2007.hydrate_rev.pdf
Shooting a pellet gun at a picture window.
We have cracking ice.
We have cracking sediments.
Whats really funny to me is that expansion of hairline cracks is the number one cause of structural failure.
Engineers understand this phenomena in detail (Mean Time To Failure) for mechanical systems from airplanes to bridges yet for some reason its practically scoffed at by many geologists.
Yet they deal with both volcanic eruptions and earthquakes driven but this issue.
The world can and does crack.
bingo
I should have been more clear, the "cracks" are already present. Given that, perhaps a better analogy would be a steel bar with a small notch cut around it which will snap earlier than one without a notch. Use the notched bar in constructing a tower and you get closer to the global picture.
As I see it there are 2 major unkowns with regards oceanic methane clathrate destabilisation and land permafrost melt. Both pertain to the future of sea-ice cover. That's because sea ice is the factor that could most amplify the regional warming of the Arctic.
1) How fast will we see the transition to a seasonally ice-free Arctic (no ice in summer).
There's the fast path (1 to 2 decades) or slow path (final quarter of 21st century as per model studies). It should become clear by 2010 whether 2007 was a one-off from which the sea ice will recover or whether a new more rapid loss regime is in place. If it's a new regime we could well be on a fast path transition to a seasonally ice free state. This is crucial because of the ocean warming that comes with open summer seas, the newly open areas in 2007 were as much as 5 deg C above average. Furthermore open water allows water vapour to transport to the atmosphere enhancing storminess which has a pivotal role in mixing warm water from the surface into deeper layers of the ocean. Researchers in 2007 noted areas of open water kept open into December by powerful storms fed by water vapour and heat fluxes from the open water.
After the transition to a seasonally ice free state there is the transition to a perennial ice free state. It would take a massive increase in GHGs (Greenhouse Gasses) to sustain large areas of open water into the cold of the sunless winter, that's because the winter regime is dominated by infra-red heat loss into space. It's precisely that infra-red that is blocked by GHGs. However Abbot & Tzipperman (1) have suggested that clouds could provide a mechanism that substantially lowers GHG requirements for an ice-free state.
2) How fast will heat from a warming ocean penetrate into the ocean floor sediments, this is unkown.
Because of these 2 key unknowns I'd be dubious of anyone who's saying we will see substantial clathrate destabilisation from the Arctic ocean shortly. The point is we just don't know. But we know enough to know it cannot be ruled out, and that the further we go down our current emissions path the more we run the risk. The danger is once it gets started it may not stop (given the additional support of our past emissions). In the past year I've gone from viewing AGW as the most pressing issue to viewing Peak Oil as the most pressing. But if we ignore either it's at our peril.
Back to lurking. ;)
1. Sea ice, high-latitude convection, and equable climates. D. S. Abbot and Eli Tziperman. GRL 2007.
www.seas.harvard.edu/climate/eli/reprints/Abbot-Tziperman-2008a.pdf
PS interesting article about Siberian land carbon - http://www.guardian.co.uk/environment/2009/mar/10/climate-change-copenhagen
The relevant Copenhagen Conference Poster Session abstracts here - http://www.iop.org/EJ/toc/1755-1315/6/4
Also, some of the permafrost in Alaska is within 1C of melt temp, iirc. A lot of methane undersea and in other areas is also close, within a 2 or 3 degrees, iirc.
Ah, here's one of the references for sea floor clathrates:
http://www.climateark.org/shared/reader/welcome.aspx?linkid=120442
I would like to point out a simple observation: The scientists are doing amazing work, but they have underestimated badly on the speed of climate change. This is not something risk analysis suggests is wise to continue to underestimate.
Methane is currently rising. New areas of bubbling methane have been found. Large ones. What more do we need to know?
Climate change is here and now, not in a decade or a century. It is current events. We ignore this at our peril.
Cheers
We don't even need to invoke clathrates to foresee doom; the ground carbon store in permafrost is estimated at over a trillion tons. When the permafrost melts, microbes get busy and metabolize all those yummy organics. CO2 and methane are the result.
That kind of begs the question of how that carbon ever accumulated in the first place during past interglacials. Coming from Scotland I'm aware of the awkward little fact that peat bogs are actually usually a carbon sink when they are not covered in permafrost. Maybe when dealing with an educated audience you shouldn't insult people's intelligence by using transparently dubious scare tactics? Better science would mean fewer Stephen Macintyre type debunkers leaving people on the right wing of the political spectrum with the impression that all of AGW is a politically-motivated hoax.
Not scare tactics, I promise:
Vulnerability of permafrost carbon to climate change: Implications for the global carbon cycle (pdf)
When glaciers disappear, the bugs move in
:X
Obviously, it accumulated abiotically!
Not sure if that is an attempt at humour or not but in other contexts environmentalists have no problem admitting the following:-
http://archive.greenpeace.org/climate/database/records/zgpz0034.html
While tropical regions store carbon in vegetation, soil is now understood to play a larger storage role in temperate regions. Total carbon stored in British soils, for example, is estimated at 22 billion tonnes, equivalent to more than 100 years of carbon dioxide emissions from power stations and vehicles. Researchers from the Institute of Terrestrial Ecology in Edinburgh have found that Scotland's peat bogs store 75 percent of the organic carbon tied up in soils and vegetation in the UK.
There's a difference between something being carbon storage and its being a carbon sink.
Peat bogs store carbon laid down some time ago. They don't absorb carbon, and if heated up, dried up, or cut up and burned they release carbon. Imagining that because peat bogs store carbon means that they absorb it is like imagine that because an oil reservoir stores oil, more must be growing abiotically.
Soils store carbon, and can absorb or release it over the course of a year depending on conditions. If you let lots of things grow, they store carbon; if you cut everything down and leave the stumps for the sun to dry out, they release carbon.
The carbon cycle is fairly complex, and many of the details are not well understood. But it's plain that the extra we're putting in exceeds the cycle's ability to process. Some ask how we can be uncertain about the details and still claim to know that humans are causing these problems, and these problems will get worse in the future. Well, you don't have to know all the details to note the general trend.
It's rather like getting drunk. I don't have to know about that alcohol is processed in my liver by alcohol dehydrogenase which is a dimer, that its coenzyme is nicotinamide adenine dinucleotide, that zinc is required for coordination, and so on until the end result of the alcohol turned into an aldehyde. It's pretty plain when my consumption of alcohol has exceeded my body's ability to process that alcohol. I get tipsy and start acting like a dickhead, so it's time to cut back or even stop. People understood this long before enzymes were discovered.
Likewise, we don't have to know all the precise details of the carbon cycle to understand that we really need to stop burning so much stuff.
And since, as this site is so fond of telling us, that stuff is going to run short some day, even if burning coal gave us vitamin C and burning oil did nothing more nasty than making pretty girls smile, at some point we'll have to stop. At some point, we have to rely on electricity from renewables and/or nuclear. May as well start now.
Environmentalists don't really have a problem "admitting" that well-managed soils store carbon. After all, that's an excuse not to cut down trees, and we're all tree-hugging hippies, right?
Peat bogs absorb huge quantities of carbon based on old vegetation created through photosynthesis that's why Scottish peat bogs have a carbon content equal to 75 years worth of carbon dioxide emissions from power stations and vehicles in a UK context. That's a lot of carbon so it should go without saying that peat bogs represent a sink in the carbon cycle. Melt them out and odds on you are going to slowly start generating more peat again just as happened in former areas of permafrost in Scotland at the end of the last ice age. I know this isn't part of the script that you have been trained to repeat on boards like this but your scare tactic doomsday scenario is far from the only possible outcome. I would point you back again to the fact that these permafrost covered peat bogs would already have melted at least once since the last Ice Age during the Holocene Optimum with no catastrophic warming episode. Do a bit of googling and you'll find the Siberian climate was wetter as well as warmer at that point:-
http://www.citeulike.org/group/1174/article/1307193
Annual precipitation in Siberia was predicted to be 95 mm greater in the mid-Holocene than now. Most of the increase was concentrated in East Siberia (154 mm average increase). The precipitation anomalies are small in the south. Large precipitation anomalies are found in central and northeastern Siberia. This location corresponds rather closely to the large anomalies in January temperature in East Siberia. The annual precipitation Increase was > 200 mm more than present precipitation in Yakutia. This increase corresponds to the deep penetration of moisture-demanding dark-needled species (Pinus sibirica. Abies sibirica, Picea obovata) into East Siberia in the mid-Holocene, where currently only drought-resistant light-needled species (Larix spp.) are found. Another area of increased precipitation was along the Polar Circle in West Siberia and at the base of the Taymyr Peninsula in East Siberia. In combination with 2-5 degrees C warmer summers, moister climates there allowed forests to advance far northward into what is now the Tundra zone
Kiashu's explanation was very good -- maybe it would help to consider that deep permafrost extends down to hundreds of meters and took hundreds of thousands of years to form. This is sequestered carbon, i.e., carbon that is not available to the global carbon cycle. It hardly beggars belief that 1 trillion tons of carbon, or more, are sequestered down there.
Plants certainly were the source of this carbon way back when, but that carbon has been locked in permafrost through several glacial cycles. Until now.
these permafrost covered peat bogs would already have melted at least once since the last Ice Age during the Holocene Optimum with no catastrophic warming episode.
You are neglecting the amount of carbon that has been added to the atmosphere over the last century; humans weren't burning fossil fuels in the Holocene, so CO2 levels were lower, hence the combination of AGW and methane clathrates wasn't a problem during that time period.
The problem with that line of argument is that increased CO2 levels fertilize plant growth through photosynthesis thus increasing peat formation and enhancing the role of the peat bog ecosystem as a carbon sink. Peat bogs are formed at high latitudes in flat areas with poor drainage due to low surface evaporation. That is still going to be the case over much of Siberia just as it was in the Holocene Optimum and past interglacials because increased atmospheric CO2 levels are not going to change the surface topography.
Except that they don't, always, and commonly you get increased growth for a bit, then it levels off as the plants adjust to the new CO2 concentrations.
And the conditions going along with the increased CO2 - high temperature, rough weather - don't help plant growth, either.
For example, articles here, and here, and here.
And of course, the high temperatures mean the ocean's ability to act as a carbon sink declines, while the increasing concentration of CO2 in the water turns it more acidic, killing off life in it, as discussed here.
When peat bogs heat up, they release CO2.
You'd know this stuff if you'd done the reading you claimed.
Exiled Scot, I'm not sure what you're getting at. Are you arguing against the existence of the permafrost carbon store?
No I am pointing out that when these peat bogs are unfrozen as has happened in the Holocene Optimum and past interglacials they typically act as carbon sinks. That is why there is so much carbon there in the first place.
We don't seem to have a good tight timeline handle on the entire sequencing during the interglacials, and though the peat permafrost is the case in point here, the volume of permafrost gravel beneath the tundra is mind boggling. Considering that the gravel is glacial outwash and that arctic regions are now arid to semiarid, that our data points could be closer and that the full range of changes are enormous, there is plenty of wiggle room in every interglacial model.
About 5 years ago scientists started voicing concern about the fact that these Siberian peat bogs would go from being a constant in global climate model terms thanks to the permafrost to a variable upon thawing out and pointed out (possibly motivated in part by a desire to attract research money) that although they normally act as a carbon sink the potential is there for the opposite to be the case on a very large scale given the sheer quantities of carbon involved. Environmental activists then latched onto the concern expressed and started reporting it as if it were proven scientific fact. Unfortunately this whole AGW issue has been politicized and groups like Greenpeace on the one hand and individuals like Rush Limbaugh on the other cherrypick only the snippets that fit their agenda and ruthlessly propagandize on that basis.
No arguement on all the competing posses screwing up the picture. Considering all that is at stake that is probably unavoidable. UAF is doing some very basic on the ground research on what warming would do the arctic vegetation, but on a fairly tiny scale. One of their findings that interested me was the tendency for a warmer tundra to support woody plants (stunt trees and shrubs). I saw no estimates on whether this change would be a carbon positive or negative influence.
Huge amounts of ice free arctic water will no doubt change cloud cover and precip. We don't have the data to make decent projections. I had noticed the clouds from SE Asia monsoons drifted north and then headed back east overland to Alaska and gave us our summer rains for most of the last dozen years. The last few years clouds seem to be generated over the open water above Siberia and head our way the last half of summer. My observations are intemittant and far from professional, so I'd love to see a twenty year animation of what is really happening. But that change is happening is obvious up here. Just what that means in the short term and where tipping points are is very much in the realm of conjecture.
None the less, and despite the din of the screaming, I have long had concerns that we humans are now capable of doing something
"to turn the sun again' us"
We won't survive that, so the utmost caution is advised.
On a brighter note these two hour March sunsets are lovely, late winter is beautiful in these parts
I am pointing out that when these peat bogs are unfrozen as has happened in the Holocene Optimum and past interglacials they typically act as carbon sinks. That is why there is so much carbon there in the first place.
It's almost certainly not the case that the net carbon flux from thawing permafrost is into the ground; we have a lot of evidence that the net flux is into the atmosphere. Check out my link upthread, especially the section titled "The fate of carbon from thawed permafrost" and Figure 6:
During the summer the surface layer of the tundra melts and plants are able to grow. As they die they add to the biomass they grew in, building up layer upon layer. That's how the glacially scarred wasteland of bare rock, rubble and erratics can (given time) become tundra and at lower lattitudes peat bog. Gradually over the seasons the surface layer is buried and it's biomass gets locked in the permafrost where it cannot decay. The accumulation is a slow process, but it happens for millenia.
When the permafrost melts during eras of warming (warming for whatever reason, be it Milankovitch cycles or human activity) bacterial activity is able to act upon it. So CH4 and CO2 are released. This process will have been active in the rise out of all of the glacials of the Pleistocene. In peat acidity and waterlogging are the factors that stop/limit microbial activity. During drought peat can release it's CO2 very rapidly, by burning.
Someone really needs to do an article on Jevon's Paradox in a post peak world.
JP can't possibly hold true in a post-peak world. If NEW TECH lets me use 1/2 as much fuel to do job X, then all that will change is that two people will now do job X, using the same amount of fuel. Right? Correct. JP seems to be holding... but... that doesn't mean we can use any more resource, because we are still now post peak and can't get anymore to market any faster.
So what are we left with? Same amount of fuel used; twice the job done. This equates to growth (or more likely, less shrinkage) and will be good for the economy, buying us time and extra resources to get those alt energies you speak of.
How is that a bad thing? Seriously, people, stop with the Jevon’s Paradox. This ain’t the 1880’s and this kind of thinking now is just too late. Efficiency is good.
I thought it was clear than Jevon's Paradox, the rebound effect didn't apply in a post peak world? Within a declining envelope of total energy post peak, there is no scope to increase absolute consumption. Is this contentious?
I think it is a valid point that energy saved by increased efficiency is not globally saved but used by others. But the same is true with regard to alternative or new sources of energy. Suppose we would increase wind energy dramatically - oil, gas and coal would still be burned in similar quantities. However since part of the demand is covered otherwise, prices would be cheaper leading to more demand and maybe a little less production. The same holds true with increased efficiency: Increased efficiency is a means to cover part of the energy demand other than by oil, gas and coal. This leads to a softening of future price spikes and some more ressources left in the ground for future generations.
So although I agree with the effect I would assume it eats up only part of the energy saved by efficiency increases.
Since I seem to be the designated advocatus diaboli...
As long as you've got your piece in the pipeline, maybe you could prepare something for the comments explaining why CHP district heating is incompatible with CCS?
CHP is not incompatible with CCS, and indeed the Dane's have CHP plants fitted with CCS - I believe. You make a judgement to build super-efficient generating plant and to then sacrifice some of the efficiency to limit environmental externalities.
In the UK, coal fired plant is 37% efficient. There they want to either retrofit old plant or build new plant with CCS that will reduce the energy efficiency to 30%. So we will have to import more coal - and energy imports are already bankrupting our country.
The situation in the US is a bit different, since you have so much coal. But i'd still argue that its better to extract 3* the energy from that coal than to simply blast 60 to 70% off as waste heat.
Euan,
I have just been reading the letter's of two "experts" on this matter and as usual there is a conflict of opinion.
I am no expert on the steam cycle, but I think in simple terms, the condensing takes place at much below atmospheric pressure. Whilst there are huge quantities of latent heat from the condensing of water, it is low grade
at the sub atmospheric pressures involved. This is done to maximise the thermal efficiency of the turbine. Neither "expert" says it cannot be done, as usual it is an argument concerning the economics of doing it and for what the heat is useful for. The climate also affects the econmics because low grade heat can be more useful in cold weather than in hot weather.
The same problem occurs with refrigeration plant. In the food industry there is loads of waste heat from the refrigeration systems that is often dumped into the ambient air. The problem is it is in two forms; super heated gas which is high grade and can be used to heat water effectively. I think this high grade heat is about 20% of the total (I am going off memory, so I will stand being corrected). The next stage is the condensation of the refrigerant, which in quantity is 4 times greater, but is low quality and difficult to use because condensing normally occurs close to ambient temperature. In winter, this low grade heat can be used for space heating, though this is often not economic, in summer its use is very limited.
When god made the laws of thermodynamics, he did not realise man would be daft enough to try and exploit them.
Wet Combustion for CHP - Improved Efficiency and water cleaning at the same time
It is quite possible to improve Combined Heat and Power (CHP) by burning fuels in the presence of water (dirty water or even sewer water). Normally, using "dry combustion" their is only about 10% water content in the exhaust from combustion. If the combustion is done with the injection of small amounts of water all along the combustion zone (of a combustor), the amount of water content in the combustor gradually increases along with the temperature.
You may ask, "Why would we want to do this?" Well, "wet combustion" increases CHP efficiency. Also, dirty water can be burned and many contaminants (including hydrocarbons) will be burned. In the case of the burning of sewer water, you get a triple advantage. You destroy any bacteria and other biologically active species in the combustion zone (at about 1000C), and if it is done properly all of the carbon-containing molecules will be converted into CO2. Also, the water content of the exhaust can be as high as 30-40%, which can make the CHP efficiency 10-15% higher. Finally, after trapping the heat from the water for the heating portion of CHP, the water can be condensed. It is MUCH cleaner than the water that entered the combustion chamber (effectively it has been steam distilled, or better). At the very least it can be released into the environment without as much concern, but it can also be recycled for drinking water. Given the water of combustion (burning of the hydrogen in hydrocarbons to make water), in the exhaust, it is possible to run such a process to produce a net amount of clean water.
So, it is quite possible to procure the advantages of CHP for CO2 reduction (with higher efficiency) AND to clean water at the same time.
When you apply the existing technologies to new situations they may not be as well suited as alternative technologies that have been overlooked in the previous situations.
Hope that this is helpful,
Ian
I dont get how that would work. CHP like any other power source usig a steam cycle need as hot steam as possible for maximum efficiency and how would introducing moisture in the combustion help that? I would rather try to get the fuel even dryer and use a gasifiaction cycle to get fuel for a high temperature boiler or gas turbine with an additional steam cycle for maximal efficiency.
But introducing water ought to make a higher fuel load possible in a fixed size boiler and then can the energy transported out of the boiler via the steam be recovered in a condencer heating district heating water. But that do not provide any additional high value electricity. It is common in Sweden to condence the wapor in the smoke to make garbage incineration more efficient and get more heating kWh out of undried biomass fuel.
Could you please explain how introducing water could help CHP plant efficiency?
Magnus,
You are correct that a higher water content in the combustion zone allows the burning of more fuel in the same space. There are other advantages:
1) One of the dominant failure mechanisms of combustion systems and the most important design consideration is the maximum temperature (at any time) that the components will be exposed to. When dry combustion is used, the temperature along the center line is usually much hotter than at the walls, for example. A typical temperature differential is about 600C between the wall and the hottest point along the center line. Doubling or tripling water content dramatically lowers the temperature difference. The temperature differential can often be reduced below 100C in a wet combustion system. This has all kinds of advantages including reducing the NOx production (in air combustion) and reducing soot production (along the walls). However, it also allows for a higher average temperature because the peak temperature is reduced. A higher average efficiency leads to higher combustion efficiency (Carnot efficiency increases as the average temperature in the combustion zone rises). Also the time average temperature change is also dramatically reduced (again because the average BTU content per unit mass dramatically increases with steam content). This increases the life-time of the components.
2) If you burn more fuel in the same space, the capital cost of the system for a given quantity of heat output is reduced
3) Dirty water can add a few BTUs of "free fuel" to the cost of the system (along with cleaning of the dirty water!)
4) Steam engines are very old and they have been improved a great deal since they were first introduced. The thermal to mechanical coupling efficiency in a steam turbine (or a wet combustion turbine) between a high water content exhaust is higher because there are more BTUs per unit volume (and mass) in the gases and especially when they are condensed to liquid water. The principal thermodynamic reason is the huge heat of evaporation of water. (dominates the climate system too!!!) ==> hydrogen bonding of liquid water is a powerful force!!
There are several patents and papers on this subject that I could refer you to if you like. The traditional reason for NOT doing wet combustion is that MOST applications of combustors for electricity production simply dump the waste heat with the exhaust and they are not used for CHP. CHP changes the economics and thermodynamics heavily in favor of wet combustion. BTW, it also dramatically reduces NOx (and unburned fuel) because the max-min temperature differential in the combustion zone(the principal reason for the ugly trade-off between these two pollutants) is so dramatically reduced as the amount of water (and the BTU content/unit mass of the exhaust increases). Improving the time to profit by reducing the up-front capital cost per unit BTU is a significant added bonus.
Again, the design and economics of the current dry combustion systems were created with a simple (non-CHP) combustion paradigm in mind. Wet combustion is a whole different technology with a completely different paradigm (IMO much more appropriate for CHP).
I hope that this is helpful to you.
Ian
Ok, combustion is an extremely complex area of physics and optimization and I only understand a very tiny part of a mind boggling huge area.
Wet steam turbines were a new idea for me, I got the impression that you realy do not want to have condensation within the turbine or water in the steam flow since it erodes the turbine blades.
But I do know that old jet engince used water injection to increase the mass flow and thrust in feeble 50:s jet engines and that water injection can be used in gas turbine compressors to combine cooling that increases the compression efficiency with increased mass flow but then you keep it in the steam phase throughouth the turbine.
From my POW are CHP plants identical to electricity only plants with the minor changes of usig a shorter turbine with less expanson that condenses at a higher temperature and preassure to heat district heating water and you can also recover heat from the smoke via heatig more district heating water. The turbine part can then get more complex if you want to bleed steam for industrial uses or run it with different combinations of heat and electricity production but I dont get how that affects the boiler. I got the idea that boiler optimization idealy should be driven by the fuel characteristics and then it becommes more of a headache if the steam need varies a lot.
Magnus,
You are correct about Turbines not wanting to have condensation inside them (corrosion is a BIG issue). However, recycling the heat into a system using water injection is MUCH easier than for other combustion systems and is highly desirable to increase thermal efficiency. This is because a condenser can be inserted AFTER the turbine to condense the steam to water and use the incoming (cold) water as a heat sink which is then routed into the combustor. Condensers can be just a counter-flow double concentric tubes with cold water flowing through an outer jacket and the hot exhaust condensing on an inner surface. That condensed water is usually quite clean and it can then be used directly for CHP purposes (the outlet temperature of the condensed water is dependent on the design goal and the surface area of the condenser).
The incoming cold water is then heated with some of the waste heat which is then used for injection into the combustion zone. Pumping and pressurizing water (an incompressible fluid) is extremely energy efficient. For example, it take ~100X more energy to increase the pressure of air from 1 atm to 10 atm (0.1MPa to 1.0Mpa) than to increase the pressure of water the same amount. If you pressurize water to 10atm (1.0MPa) its boiling point increases to about 190C. You can therefore add a lot of heat to incoming ("cooling") water without it boiling (a key design consideration). This makes the efficiency of the system even better because you need less water to recycle the heat. Also, the whole point of combined heat and power is to use the exhaust and any waste heat from it for district heating or other purposes. Heating water for a swimming pool is a good example in a municipal setting.
Note, that a condenser to condense the water of combustion from a dry combustor is possible but its surface area must be HUGE (high capital cost). When you have 30-50% water content in your exhaust from a wet combustion system, condensing the water is MUCH easier (the relationship between humidity and the cost to condense it is not linear!). Once the water (dirty) has been combusted at 1000C you get any organic contaminant in the water being destroyed by hydroxyl radicals (very violent and efficient oxidizers which are produced by the breakage of an O-H bond in water at high temperature). Note that the transfer of heat is very efficient with those high steam concentrations so local "pockets" of low temperature are MUCH less likely than in a dry combustor. So once the water has been converted to steam in the combustion zone, the combustion gases convert a high percentage of their energy to electricity in a turbine (lots of energy in the steam). The remaining amount of energy in the combustion gases (40-70%) is left-over in the heat of evaporation of all the steam leaving the turbine. Converting that heat into usable heat in a CHP operation is efficient because you can readily convert (at least) 75% of the steam to water in a condenser (easy). That means that nearly all of the energy content of the steam that condensed has been captured in incoming (cold water) or for CHP purposes (i.e. heated water or air-less efficiently). Once the steam condenses at atmospheric pressure it has dropped about 80-90% of its energy content. The key to the whole operation for CHP is to use STEAM to condense to water to transfer the VERY high content of steam into water. Imagine CHP without that steam to water condensation!! Imagine trying to heat up water for swimming pool with only hot gases in contact with a heat exchange surface. Imagine the relative contact area. Steam converting to water transfers at least 10X (probably more like 100X) more heat per unit surface area than a dry hot gas. That is why we use a steamer to heat our vegetables!!
Most of this explanation would be "old hat" to a 19th century steam railway locomotive engineer or designer. Ironically, those steam engines were relatively efficient because of the use of steam! Of course, he wouldn't have known anything about NOx and wouldn't have cared about CO2, but the principles haven't changed. Water (and steam) are simply amazing things!!
Ian
I get the impression that you are mixing water flows with different chemical criteria, or in simpler words different cleanliness. This does not make sense for me.
You seem to be proposing a gas turbine type of plant like a PFBC with water injection in the combustion zone? Those are complex beasts since you need to compress the combustion air and clean the combustion gases enough to not wear down the power turbines from dust erosion.
And you description of a condensation heat exchanger is unfit for heat exchanging between a liquid and a gas medium where you handle the steam flow from a steam turbine.
I disagree. The Hydrogen Economy was around, afaict, in the wet dreams of futurists long before AGCC started being vigourously debated. The modern (read: corporatised) Hydrogen Economy has simply latched onto AGCC as a means to promote itself. Given that the vast majority of commercially-produced Hydrogen currently comes from Fossil sources, and given that entropy is unavoidable, the Hydrogen Economy can only make any sense when we already have an excess of Green Power (and even then, you'd probably use Anhydrous Ammonia as an energy carrier instead).
Will this be using the micronised coal water slurry in a slow speed diesel engine? as aluded to here (PDF)
The document shows that the most efficient way to move the coal would be by rail or boat which would help towards TOD development if used in combination with CHP, as you would be moving a large volume of people and coal in a smaller area.
Such a system could also make use of natural gas (and / or biogas) with direct injection to lower emissions (speculative)
If you can get a pure enough output of CO2 you could just vent it into a large vertical farm or greenhouse, which could also filter water and deal with compostable/digestable wastes.
Spending a fortune burying CO2 in the ground seems nonsense to me when its cheaper to make less of it (more efficient use of fossil fuels, expand nuclear & renewable electricity & electrify transport) then use it as a resource rather than a waste product.