Naked Science Forum
Life Sciences => The Environment => Topic started by: Mark Peterson on 23/02/2010 08:30:01
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Mark Peterson asked the Naked Scientists:
So there is an obvious need to change the way we produce energy to more efficient ways.
I hear a lot about that, but simply changing the output of carbon into the atmosphere and not changing the input into the geosphere, we are not solving but only slowing the problem.
Are our carbon sinks capable of catching up to move carbon in the atmosphere to lower levels? Is there an invention to do this faster?
I think that both angles is the only way to solve this problem.
Thanks.
What do you think?
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Carbon sequestration is in its infancy. With the clearing of land for human habitat, which greatly decreases carbon sinks, it does look bleak.
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To echo Jim Bobs comment - the capacity and extent of known carbon sinks is uncertain, and the effects of potential warming on the better constrained sinks is also unclear.
The obvious example of this is peat bogs - when in good condition they are an effective carbon sink, however if they start to dry out, whether through mans activity (cutting/ harvesting for fuel or horticulture) or due to changes in rainfall patterns / temperatures; they become carbon emitters.
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The largest carbon sink is our oceans. About 70 percent is oceans, and the average depth is around three thousand three hundred feet (1000 meters). Only two percent of the water is freshwater, the rest is our oceans. And December 2009 was the second warmest ocean temperature on record, according to NOAA’s National Climatic Data Center, based on records going back to 1880. The temperature anomaly was 0.97 degree F above the 20th century average of 60.4 degrees F.
That means that the waters waves are moving faster now than it did a hundred years ago as there are more kinetic energy stored in it, due to its heat uptake. Also that it breaths out more humidity, creating worse storms, from category three to category five. We will see more of category five every decade now. "it is likely that greenhouse warming will cause hurricanes in the coming century to be more intense on average and have higher rainfall rates than present-day hurricanes." from Global Warming and Hurricanes (http://www.gfdl.noaa.gov/global-warming-and-hurricanes)
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Most scientific opinion agrees that between 1961 and 2003 ocean temperature has increased by 0.1 degree Celsius from the surface to a depth of 700 metres. This temperature increase is based upon many millions of historical measurements. It seems therefore that the oceans are gradually warming but that it's not conclusive, it is persuasive.
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And it also means that the oceans are acidifying. A new model, capable of assessing the rate at which the oceans are acidifying, suggests that changes in the carbonate chemistry of the deep ocean may exceed anything seen in the past 65 million years. accidification (http://www.physorg.com/news185444922.html). What it means is that the water is fastly becoming unusable (unbreathable) for most of the fish we eat although some species seems to thrive in it, like jellyfish. Google on 'jellyfish invasion' and see what you find. And I'm not talking about over-fishing now.
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Iron and the Carbon Pump by William G. Sunda
The concentration of carbon dioxide (CO2) in Earth's atmosphere has risen by ~38% since the start of the industrial era as a result of fossil fuel burning and land use changes; if current trends continue, it is projected to increase further by at least a factor of 2 by 2100. About a quarter of the CO2 emitted through human activities has been absorbed by the ocean. On page 676 of this issue, Shi et al. show that the resulting acidification of ocean surface waters may decrease the biological availability of iron, which could in turn reduce the ability of the ocean to take up CO2.
Beaufort Laboratory, National Ocean Service, National Oceanic and Atmospheric Administration, 101 Pivers Island Road, Beaufort, NC 28516, USA
--End of quote--- Science magazine 5 February 2010 (http://www.sciencemag.org/cgi/content/summary/327/5966/654)
And our oceans are loosing some of their appetite for CO2 too, meaning that they don't take up as much CO2 as they used too earlier. " The oceans near Antarctica are thought to have one of the healthiest appetites for greenhouse gases. Their surface waters can guzzle around 15 percent of all the carbon dioxide produced by people, which comes mostly from industry and automobile emissions. The new study found the oceans are mopping up only about 10 percent of carbon- oxide, requiring projections for future levels of greenhouse gases to be bumped up accordingly. " Antarctic Oceans Absorbing Less CO2 from 2007. (http://news.nationalgeographic.com/news/2007/05/070517-carbon-oceans.html)
For an estimate over how much the oceans already have taken up from us you can look at National Geographic News 2004 (http://news.nationalgeographic.com/news/2004/07/0715_040715_oceancarbon.html) The sources ain't that new and I don't expect the facts to have become any better since those research was done.
"Sabine and researchers from the United States, Europe, Australia, South Korea, Japan, and other nations have now completed the most comprehensive survey of ocean carbon chemistry.... In the new study, however, researchers collected direct samples on dissolved carbon dioxide levels in oceans around the world throughout the 1990s. Data were collected at some 9,600 sites around the world on 95 separate research voyages. Their results suggest that the oceans have taken up 48 percent of all carbon dioxide emitted from fossil fuel burning and cement manufacture (a major source of the gas) between 1800 and 1994. "
So our greatest heat sinks seems to be getting saturated, as for the heat distribution in the oceans there are a lot of dispute going on, but considering the few probes we use as compared to the volumes of water we're speaking about here (around 326 million trillion gallons or 1,260,000,000,000,000,000,000 liters) being in a constant cycle, evaporating from the oceans raising as humidity and raining down, to then flow back into the ocean, we can't really say for sure how this trend will end.
We can't do anything better than what nature already have provided for us, the talk about storing CO2 and leading it down the ground or the oceans is not only stupid, it reeks also of an earlier 'Jules Vernian' type of thinking, where all solutions was seen as being linear, aka 1+1=2. We know by now that 'linear solutions' are a very small part of any system and not really true for any larger system that I know of, and neither for small ones either. Earth is definitely a non-linear system, remember that butterfly flapping, changing the weather a thousand miles away? There are no 'simple solutions' to this problem. What we really can do is to stop adding to the problem in form of man made CO2, and that would be a very good start.
Because we have an source that could accelerate it out of all proportions that we just very recently have started to debate. Methane..
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"The research published in the journal Science shows the permafrost under the East Siberian Arctic shelf, which was thought to be a barrier sealing methane, is perforated. Scientists from the Russian Academy of Sciences say more methane will be released if the permafrost is further destabilised. CSIRO spokesman Pep Canadell says the study identifies a possibly overlooked source of methane in the atmosphere.
"Maybe before we were wrongly attributing it to cows or rice paddies or whatever, all the major sources of methane we have. And now when we measure fluctuations in the atmospheric methane concentration we can more properly attribute where these sources are coming from."
He says the study provides, for the first time, an estimate of the contribution of the Arctic to overall methane emissions. Current average methane concentrations in the Arctic are the highest in 400,000 years.
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Outside Australia (ocean) there are natural Gas deposits waiting for the picking. To transport this gas you either need pipelines or you will need to freeze it to around -161 C. The project ‘Gorgon’, sat in motion by Chevron, plans do use those fields outside Australia with Exxon and Shell jumping on the train. So now you have super tankers on the seas with ‘super-cooled, super-concentrated natural gas’ (That’s what happens when it gets frozen. The density of a gas goes really up, way way up when it becomes a liquid..) . You might ask yourself. Why don’t they take it from USA (Carolina f.ex) instead? “All the energy America needs for the next 100 years lies under the sea off the coast of South Carolina.”
Just one problem: Digging it out might cause a global climate disaster.”
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Methane is the principal component of natural gas, and massive amounts of it are trapped in reservoirs beneath the sea floor and under a layer of the ice-like substance. The scale of the resource is spectacular. By some estimates, methane hydrates contain more energy content than all other known fossil fuels combined. Two small areas located roughly 200 miles off the coast of Charleston, S.C., contain enough methane to meet the country's gas needs for more than a century. And this is only one of at least two dozen similar reservoirs discovered in U.S. coastal waters since the early 1970s.
The paradox is that while gas can be extracted from methane hydrates, doing so poses potentially catastrophic risks. Methane hydrates are frozen water molecules that trap methane gas molecules in a crystalline, lattice-like structure known as a hydrate. Unlike normal ice, hydrate ice literally burns — light a match and it goes up in flames. As temperatures rise or pressure rates fall, the hydrate disintegrates and the water releases the gas. A substantial amount of evidence suggests that weakening the lattice-like structure of gas hydrates has triggered underwater landslides on the continental margin. In other words, the extraction process, if done improperly, could cause sudden disruptions on the ocean floor, reducing ocean pressure rates and releasing methane gas from hydrates.
A mass release of methane into the sea and atmosphere could have catastrophic consequences on the pace of climate change. More than 50 million years ago, undersea landslides resulted in the release of methane gas from methane hydrate, which contributed to global warming that lasted tens of thousands of years. "Methane hydrate was a key cause of the global warming that led to one of the largest extinctions in the earth's history," Ryo Matsumoto, a professor at the University of Tokyo who has spent 20 years researching the subject, told Bloomberg in December.
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And if you wonder how much Methane we might have stored? Estimates are that more than 10% of the world’s hydrates are located on-shore in arctic permafrost; and a sizable — although not quantified — amount are in relatively shallow arctic seas. These are susceptible to melting from warming.
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Methane is a greenhouse gas that is 60-70 times more potent than carbon dioxide (CO2) over a twenty-year period (or 25 times over a hundred-year period). Human-caused methane emissions are currently contributing some 20-30% of the observed global warming effects. These include: Energy, Landfills, Ruminants (Livestock), Waste treatment, and Biomass burning.
However, there are two additional sources of methane that are just now bubbling to the surface. One source is the methane hydrates (also called clathrates) that have been frozen since the last ice age in the permafrost lands of Russia, Alaska and Canada, but are now being released as the permafrost melts. In addition, the methane hydrates, which have been long stored in the cold Arctic Ocean seabed, are now being released as the ocean temperature rises.
Estimates of the land based hydrates estimates range from 0.8 to 1 gigaton, for the sea-based hydrates in the Arctic total 1.5 gigatons of carbon, Recent research carried out in 2008 in the Siberian Arctic has shown millions of tons of methane being released, apparently through perforations in the seabed permafrost, with concentrations in some regions reaching up to 100 times normal.
Most of the thawing is believed to be due to the greatly increased volumes of meltwater being discharged from the Siberian rivers flowing north. Current Arctic methane release has previously been estimated at 0.5 Megatons (500 000 tons) per year, but now it appears to be increasing rapidly. Shakhova et al (2008) estimate that not less than 1,400 gigatons of Carbon is presently locked up as methane and methane hydrates under the Arctic submarine permafrost, and 5-10% of that area is subject to puncturing by open taliks.
They conclude that "release of up to 50 gigatons (fifty thousand millions ton) of predicted amount of hydrate storage [is] highly possible for abrupt release at any time". That would increase the methane content of the planet's atmosphere by a factor of twelve, which is equivalent in greenhouse effect to a doubling in the current level of CO2.
----------End Quote…..By Jim Stewart, PhD, October 6, 2008,----
From my post at TNS (http://www.thenakedscientists.com/forum/index.php?topic=25747.msg276353#msg276353)
So, I hope you've got your question answered now, and also can see why some people would like us to start stopping that CO2 :)
Yep, it all comes back to CO2, even that damn*d methane does. Methane have started to move big time now in the tundra and shallow waters of the arctic/antarctic, whats worse is that even if it oxidize away in a relatively short time (decades), it will do so into even more CO2. And that (sort of new) CO2 will stay in the atmosphere just as long as all other CO2.
I'll leave you with this approximation for the relative 'convection' of different molecules in the atmosphere.
---Quote—Lisa Moore, Ph.D., scientist in the Climate and Air program at Environmental Defense.--
Here's a table showing a selection of greenhouse gases, their global warming potential (GWP), and their lifetimes:
Greenhouse Gas . . . . . . . . .Lifetime years . . (100-Year GWP)
Carbon Dioxide (CO2) . . …. . . . hundreds .. .. . .1
Methane (CH4) . . . . . . …. . . .. . . 1 . . . . . . .25
Nitrous Oxide (N2O) . . . . . . . . . .114 . . . . . . .298
Hydrofluorocarbon-23 (CHF3) . . . .264 . . . .. . .14,800
Sulphur hexafluoride (SF6) . . . . ..3,200. . . . .22,800
PFC-14 (CF4) . . . . . . . .. . . . . .50,000 . . . . .7,390
Notice that the carbon dioxide lifetime is "hundreds of years", rather than a specific number. The IPCC ‘Third Assessment Report’ defines a gas's lifetime as the amount of the gas in the atmosphere divided by the rate at which it is removed from the atmosphere. That sounds simple enough, except that not all gases are removed by just one (or mainly one) process. Ironically, the gas that accounts for the greatest proportion of global warming, carbon dioxide (CO2), is the hardest to pin down. When CO2 is released into the atmosphere, about three-quarters of it dissolves into the ocean over a few decades (- Acidity -). The rest is neutralized by a variety of longer-term geological processes, which can take thousands of years.
From IPCC Fourth Assessment Report: About 50% of a CO2 increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within a few centuries. The remaining 20% may stay in the atmosphere for many thousands of years.
From U.S Greenhouse Gas Inventory Reports: (CO2) Atmospheric lifetime: 50-200 years. No single lifetime can be defined for CO2 because of the different rates of uptake by different removal processes.
From RealClimate: “My model indicates that about 7% of carbon released today will still be in the atmosphere in 100,000 years. I calculate a mean lifetime, from the sum of all the processes, of about 30,000 years. That's a deceptive number, because it is so strongly influenced by the immense longevity of that long tail. If one is forced to simplify reality into a single number for popular discussion, several hundred years is a sensible number to choose, because it tells three-quarters of the story, and the part of the story which applies to our own lifetimes.” ("How long will global warming last?")
For other gases, a meaningful lifetime is easier to calculate because one process dominates their removal from the atmosphere:
* Methane is mostly scrubbed from the atmosphere by hydroxyl radicals (a chemical reaction).
* Nitrous oxide is destroyed by photolytic reactions (chemical reactions involving photons or light) in the stratosphere.
As you can see from the chart, some gases have extraordinarily long lifetimes. Because emission rates are vastly higher than removal rates, greenhouse gases are accumulating in the atmosphere and will affect climate for generations to come.
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And if that doesn't worries me enough?
Well, I can always try to read this :)
The Science of Abrupt Climate Change: Should we be worried? (http://www.wunderground.com/education/abruptclimate.asp?MR=1)
You see, I keep arguing for Earth being a non-linear system. what that means to me is that it is vulnerable to what's called a 'tipping'. 'Tipping points' is when a 'system' goes from one 'semi stable balance' to another. When it consolidates into the new balance it will crave a lot for it to go back to the one it had before. And when the 'tipping point' is 'attained' the change goes 'real fast'. Just as that article above describes.
"What the scientists found was surprising and unnerving. They had known from previous ice core and ocean sediment core data that Earth's climate had fluctuated significantly in the past. But what astonished them was the rapidity with which these changes occurred.
Ocean and lake sediment data from places such as California, Venezuela, and Antarctica have confirmed that these sudden climate changes affected not just Greenland, but the entire world. During the past 110,000 years, there have been at least 20 such abrupt climate changes. Only one period of stable climate has existed during the past 110,000 years--the 11,000 years of modern climate (the "Holocene" era). "Normal" climate for Earth is the climate of sudden extreme jumps--like a light switch flicking on and off."
You can also take a look here.
Tipping points in the Earth system (http://researchpages.net/ESMG/people/tim-lenton/tipping-points/)
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Plants, and the oceans, are doing their best to moderate the increase of CO2 in our atmosphere. Unfortunately, the absorption of CO2 in our oceans is making them increasingly acidic. I believe this data is undisputed. The outcome is very unclear. Who would like to gamble?
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...The outcome is very unclear. Who would like to gamble?
Depends on what sort of odds you're willing to give me!
Atmospheric CO2 levels only recently (a few million years ago) dropped below 500 ppm, concentrations over the past 550 million years were significantly higher. Our present 380 ppm pales in comparison to an average concentration of over 1000 ppm during the roughly 200 million year long Mesozoic period (Dinosaurs rule the earth!!!). Life in the oceans somehow managed to not only survive, but flourish.
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I suppose it depends on how rapidly it changes. Presumably, if it's gradual enough, life can adapt.
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Exactly what period and what marine organisms were you referring to Bass? The Cretaceous? "Was a period with a relatively warm climate and high eustatic sea level. The oceans and seas were populated with now extinct marine reptiles, ammonites (extinct mollusks) and rudists (sort of reef-builders); and the land by dinosaurs." Cretaceous period (http://en.wikipedia.org/wiki/Cretaceous)
I'm not sure what you are referring to here?
"The beginning of the Mesozoic Era there was a depleted ecosystem world-wide. Many of the old life forms had just gone extinct in the Permian Extinction (248 millions y ago) , the world's largest mass extinction. The Mesozoic Era lasted about 180 million years, and is divided into three periods, the Triassic (first true mammals), the Jurassic, and the Cretaceous. " Are you thinking of sharks? Then there are extinct variants of course like Ichthyosaurs (similar to dolphins) and mosasaurs who seemed to have looked like eels. Then you had ostracoderms (jawless fish) etc?
If you mean that even though our era of 'man' might die, life in itself won't? Then I'm with you :) I too think that Earth has proved that enough times..
And it's like Geezer points out, the slower the better. If it goes to fast the fauna and flora might become too stressed, not able to migrate in time. But it's still an open question how fast it might be.
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Exactly what period and what marine organisms were you referring to Bass? The Cretaceous? "Was a period with a relatively warm climate and high eustatic sea level. The oceans and seas were populated with now extinct marine reptiles, ammonites (extinct mollusks) and rudists (sort of reef-builders); and the land by dinosaurs." Cretaceous period (http://en.wikipedia.org/wiki/Cretaceous)
I'm not sure what you are referring to here?
"The beginning of the Mesozoic Era there was a depleted ecosystem world-wide. Many of the old life forms had just gone extinct in the Permian Extinction (248 millions y ago) , the world's largest mass extinction. The Mesozoic Era lasted about 180 million years, and is divided into three periods, the Triassic (first true mammals), the Jurassic, and the Cretaceous. " Are you thinking of sharks? Then there are extinct variants of course like Ichthyosaurs (similar to dolphins) and mosasaurs who seemed to have looked like eels. Then you had ostracoderms (jawless fish) etc?
If you mean that even though our era of 'man' might die, life in itself won't? Then I'm with you :) I too think that Earth has proved that enough times..
And it's like Geezer points out, the slower the better. If it goes to fast the fauna and flora might become too stressed, not able to migrate in time. But it's still an open question how fast it might be.
You'll have to excuse my error- I was referring to the entire Mesozoic Era. Neither the Permian extinction nor the K-T extinction event were caused by a buildup of CO2 (in fact, the Permian extinction corresponds to an extreme drop in CO2). The fossil record shows diverse and abundant organisms throughout the Mesozoic. Amazingly, the Paleozoic Era, in which oceanic life also flourished, had even higher CO2 levels.
My point is simple though- the marine life that existed throughout Phanerozoic geologic time (since the Cambrian) lived with much higher atmospheric CO2 levels than CO2 levels at present. Levels would almost have to triple to reach minimum concentrations that existed throughout most of the Phanerozoic.
Obviously, catastrophic change makes adaptation more difficult (just ask the dinosaurs).
Should we examine methods to sequester carbon? Absolutely!
Will life cease to exist on earth if an additional 50, 100 or even 1000 ppm of CO2 accumulates in the atmosphere? According to the geologic record, absolutely not!
Life (and most likely humans) will adapt.
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Thanks Bass!
A serious question:
Is ocean acidity uniform, or can it vary with depth?
I'm wondering if there is some negative feedback (stabilising influence) in the system. It might go something like this:
Increasing CO2 causes polar melting which dilutes oceanic acidity which increases oceanic PH etc.
I suspect this would only work if the oceans have non-uniform PH. i.e. different PH levels at different depths.
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Thanks Bass, I see what you mean and I fully agree to your points. And in a strange way it's a kind of relief understanding this too. Not that I didn't understand what you're saying any which way.
(Even though that too should be counted as a blessing, considering my advanced age (yep, I'm over twenty one:))
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Reading myself I'm not sure what I mean?
Eh. I need a better brain, anyone 4-Sale.
"Slightly used, as good as new, only a few miles on the odometer" Sort of?
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On a similar although slightly dissimilar subject..
Read you say "Life (and most likely humans) will adapt."
For a really good, immortal read, on the net, free-4-all :)
Last and first men. (http://gutenberg.net.au/ebooks06/0601101.zip)
Reminds me of the first time I read 'The lord of the rings'. Those first forty (?) pages that I sort of jumped over then, later to become the pages that I loved to revisit. Boring I thought then :) Stapeldon's book will have the same impact on you, if you haven't read him before, but if persevering you will find a he** of a reading experience. And it's all about mankind..
England have a way of producing the best writers I know of?