# climate change in our lifetime **URL:** \ **Category:** Great Debates\ **Created:** [December 27, 2006, 2:25pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737 "2006-12-27T14:25:43Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![FRDE](https://avatars.discourse-cdn.com/v4/letter/f/e68b1a/32.png) [@FRDE](https://boards.straightdope.com/u/FRDE)\ **Post date:** [January 2, 2007, 12:32pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/101 "2007-01-02T12:32:36Z")
[QUOTE=fessie] We’ve made plenty of acid rain. [/QUOTE] We are not really sure about that, the Scandinavians moaned about the output from British coal fired power stations, but later on it seems that pine needles are innately acidic. ---
**Author:** ![FRDE](https://avatars.discourse-cdn.com/v4/letter/f/e68b1a/32.png) [@FRDE](https://boards.straightdope.com/u/FRDE)\ **Post date:** [January 2, 2007, 12:49pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/102 "2007-01-02T12:49:06Z")
[QUOTE=Don26] Can anyone make it rain? Snow? Hail? Not be cloudy? Make the wind blow? Uh, No. no. no. no. no. Why, we don’t have that kind of power. Not intentionally nor unintentionally [/QUOTE] Israeli friends told me about a project that was being considered, huge towers built in the sea designed to evaporate water and provide clouds. It could work - certainly worth experimenting with. We don’t know whether the climate is cyclical, whether it has a natural equilibrium or dis-equilibrium. What we do know is that we have no influence over China and India, so if something is happening, then we had best learn to live with it. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 2, 2007, 12:49pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/103 "2007-01-02T12:49:09Z")
[QUOTE=SentientMeat] Of all your claims, **intention** , this is surely the most faith-based - a charge you are quick to level at others here. You admit that 3 gigatonnes of CO2 per year are _not being absorbed_, but pull from your hat the assumption that this number will start to decrease (presumably _soon, ie._ in the next decade or so?). Believe me, I wish for this miracle as strongly as you, but am so overwhelmed by skepticism (see, I’ve got plenty of it too!) that it merely seems so much wishful thinking. What is the actual _mechanism_ of this vastly increased CO2 uptake? More plants, more plankton, more reflection of sunlight? Again, that would be wonderful. But it’s _just not happening_. Rainforests are being _felled_, phytoplankton is becoming _less_ productive, white regions are _melting_ to leave dark, methane-releasing regions. If your miracle doesn’t arrive within the next few decades, it might as well not bother turning up at all, so high will the concentrations be by then. And surely, given your hose analogy, the water can’t start filling up the barrel _quicker_, as though the increased pressure _reduces_ the speed of the outflow. So, would you be willing to make a bet? If the amount of CO2 sequestered shows an average increase over the next five years, in line with your predicted miracle, I will lose the bet. If it stays the same, I win. (If it _decreases_, I win _big_!) Are you willing to stake your honour (or something else if you like) on the next five years’ data? [/QUOTE] Thanks for the reply, Sentient. I guess I’m not very clear at explaining. Let me try again. No wishful thinking, no miracles, this is simple science. As human CO2 emissions (from fossil fuels, gas flaring, cement production and landuse) have increased, a curious fact has been noted. This is that not all of the increase has ended up in the atmosphere. By 1950, for example, we had released some 131 gigatonnes (Gt) of carbon (C) into the atmosphere as CO2. However, measurements of the CO2 in the atmosphere show that only 56 tonnes of it remained in the air. The rest had been sequestered by the planet (following figures in gigatonnes of C). From 1951 to 1960, we released 34 Gt, of which 22 Gt was sequestered. From 1961 to 1970, we released 47 Gt, of which 29 Gt was sequestered. From 1971 to 1980, we released 63 Gt, of which 36 Gt was sequestered. From 1981 to 1990, we released 76 Gt, of which 43 Gt was sequestered. From 1991 to 2000, we released 86 Gt, of which 53 Gt was sequestered. As I mentioned, this is a typical response of a system to disturbance, called an “exponential decay”. Consider the earth, and imagine that there are no disturbances. Then, one year, we add 30 Gtonnes of C to the atmosphere. Will it still be there in 1000 years? No, the amount in the air will gradually be reduced, year after year, until the original proportion is restored. But the reduction will not be linear. It, like most disturbances of this kind, follows an “exponential decay”. This means that every year, a certain percentage of what remains in the air will be sequestered. For CO2 in the atmosphere, this is about 3%. So the first year the earth will sequester 30 Gt x 3%, or about 0.9 Gt. The next year, it will sequester 3% of the remainder, 29.1 Gt x 3%, about 0.87 Gt. Each year, the amount sequestered will be smaller. If we continue to add more than is being sequestered, the airborne amount increases. And because about 3% of the _airborne amount_ is sequestered, the total amount being sequestered rises as well. Note that by the 1970s, the airborne amount had become large enough that more was sequestered in the 1970s than was released in the 1950s. This is why I said that if emissions do not increase, the airborne amount will level off. The amount in the air at that time will be such that 3% of the airborne amount (the amount sequestered) will exactly equal our emissions. This will be on the order of 425 ppmv. You ask “what is the mechanism”? It is the same mechanisms which have been operating since forever. One of the things about chemical reactions is that when you increase the concentration of one of the reagents, it drives the reaction in the other direction. Google “Le Chatelier’s Principle” for further information. Sure, I’d be glad to take a bet on the question. Nothing makes me happier than a bet on a sure thing. My bet is that you’ll agree with me now that sequestration is increasing, no need to wait five years. I have put an excel spreadsheet with all of the data [here](http://tinyurl.com/ybtv84) so anyone can check my figures. Take a look at the data and you can tell me if sequestration is increasing as emissions have increased. If it is, I win the bet. If not, let me know what is wrong. I have included references to the data. Get back to me on this one, loser has to apologize to the other guy. :smack: w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 2, 2007, 1:02pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/104 "2007-01-02T13:02:19Z")
[QUOTE=SentientMeat] Well, the 600ppm figure assumes an increase per year of 2-3ppm, the current level of increase, for another century. So the only way it can be “unreasonable” is if your miracle mechanism arrives, and I would hope that you could at least entertain the possibility that it _might not_. [/QUOTE] My “miracle mechanism” is exponential decay, and has been operating all along. See my previous post. In any case, average increase last ten years, 1.9 ppmv, average last five years, 2.1 ppmv, call it 2 ppmv. 93 years left in this century, current CO2 is 380 ppmv plus 2 \* 93 = 566 ppmv … w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 2, 2007, 1:55pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/105 "2007-01-02T13:55:37Z")
[QUOTE=ITR champion] **intention** , I think that congratulations are in order. You may well have set the record for the highest amount of junk science, misinformation, and distractions ever crammed into a single post at the Straight Dope Message Board. Write this one down, because it’s one for the record books. [/QUOTE] Dang, glad to hear it, I knew I’d set a record some day … You [cite](http://www.scidev.net/pdffiles/nature/tuvalu.pdf) an article and say that it’s real scientists … thank you for that citation, I hadn’t seen the article. Here’s some quotes from that article. > [@](#): > > There are two tide gauges in Tuvalu. One, operated by the University of Hawaii until 1999, sits on a small concrete wharf behind the threestorey Taiwanese-built government building. In 1993, the NTC installed a more modern and accurate gauge a few kilometres north at the country’s only deepwater wharf. One of twelve in the South Pacific, this gauge should in theory provide quantitative confirmation that Tuvalu is being engulfed, as the king tides and the wet cuffs of my trousers suggest. > > But in 2000 an NTC analysis reported a negligible increase of 0.07 mm a year over the past two decades from the University of Hawaii gauge, and a drop in sea level from the seven years of NTC data1. It was clear that the El Niño/Southern Oscillation (ENSO), which drives down sea level in the western Pacific, affected both of these records. And the international environmental group Greenpeace asked John Hunter, a climatologist at the University of Tasmania, to have another look at the data. When he adjusted for ENSO and the vertical movement of the Hawaii gauge, which is thought to be sinking, Hunter found a sealevel rise of around 1.2 mm a year2. OK, we have two scientists disagreeing about the tides. You get to choose which one to believe. I’ve had a reasonable amount of discussion with John Hunter about this very subject. In any case, John goes on: > [@](#): > > The thing that really interests me is how you reconcile the relatively low estimates of sea-level rise, which are the same order as what’s happening in the rest of the world, with the anecdotal observations from Tuvalu,” says Hunter. “It seems that the flooding reported there is bigger than 2mm a year. The extremes of high tide could be getting bigger relative to the mean sea level, although that’s disputed at the moment. In other words, he doesn’t see enough sea level rise to explain what’s going on. It is certain that the sea water is intruding into the fresh-water lens under the island … but sea level rise is not enough to cause that either. Since this is mainly happening on Fongafale, the main atoll, the most likely reason is the giant paved airstrip that they put in and have recently extended, which caps the atoll and prevents the rain from replenishing the fresh water lens. The article goes on to say: > [@](#): > > Phil Woodworth of the Proudman Oceanographic Laboratory in Liverpool, UK, has studied high tides in the Pacific to see whether they have changed since the 1970s. He says the peaks seem to be increasing, but by no more than mean sea level. Nothing unusual in the sea level changes … the article continues: > [@](#): > > The Tuvaluans have mixed reactions to these changes, and the scrutiny that comes with them. A few days after witnessing the king-tide flood by the airstrip, I talked to Carol Farbotko on the verandah of the Filamona. Farbotko, a cultural geographer from the University of Tasmania, is working on a thesis on cultural responses to climate change on the islands. In her interviews with officials and community leaders, she has found that climate is a vague, long-term concern. People get much more worked up about problems such as waste disposal, a fetid and ubiquitous problem; overpopulation; and the accelerating erosion of traditional culture in the age of the Internet and DVDs. I know Carol, her project is interesting. You seem to think that the Tuvaluans are all wrought up about this issue … she disagrees. The article also says (emphasis mine): > [@](#): > > During high tides, waves crash from the lagoon on to stretches of the new tarmac, spreading trash, coral rubble and other detritus across it. There was a time, I’m told, when the road behind the government building was set back a few metres from the lagoon, but now it is right on the sea. In itself this says nothing about sea level, because the islets are constantly changing shape: a spit forming here, an island tip disappearing there. Arthur Webb, a coastal ecologist in the Fiji offices of the South Pacific Applied Geoscience Commission, makes the point to me graphically by flipping through aerial and later satellite photographs from the 1940s on. _ **“These really are quite natural processes,” he says. “It’s part of living on a soft-shored island.”** _ > > As Webb shows me images with Second World War seaplanes and torpedo boats sitting in the lagoon, he explains how, in 1943, US troops built a makeshift seawall and land-reclamation project along the length of the lagoon foreshore. After the troops left, locals built homes and roads on this 25- to 30-metre-wide stretch of rubble, which then began to erode. Jetties and channels further altered coastal erosion and deposition patterns. The move from portable, short-lived thatch houses to Western-style concrete-block homes has added to the difficulties. Despite regulations, the shores of Tuvalu have been ransacked for aggregate for construction — an activity that makes the prospect of flooding far worse. “Beach mining is a disaster,” says Webb. Do we see a pattern here? People destroying the reefs, changing the structure of the island with fill and rubble, and then thinking that sea level rise is flooding their island? (Webb, by the way, works for SOPAC, the organization whose report you trashed for being 11 years old … as if the conclusion that reef destruction and coral mining were the cause of Tuvalu’s problems had a “use-by” date.) Finally, you had said: [QUOTE=ITR champion] So on the one hand we have actual officials from Tuvalu, and on the other an anonymous internet user. Guess who I’m going to believe. [/quote] I found the article most interesting because it goes on to say: > [@](#): > > Those sceptical about Tuvalu’s plight, including amateur scientist Willis Eschenbach, seize on local explanations such as mining to assert that fears about sea-level rise are created by hysterical journalists and environmental groups looking for a cause célèbre. Eschenbach, who carried on a spirited debate with Hunter in the journal Energy and Environment, has concluded that sea-level rise in Tuvalu is an illusion. He has used that conclusion to support an argument that there is no clear evidence for climate change. > > Webb, on the other hand, thinks that poor coastal management and climate change are acting in concert. Oddly, when he presented this sinister synergy to the falekaupule, or council of elders, in Fogafale, their reaction was something like relief; a remote and difficult problem became a local and understandable one. They learned there were things they could do to mitigate erosion — they could further regulate beach mining and carefully dredge the lagoon for the island’s aggregate needs, for example. Many scientists and people within the government insist that Tuvalu must step up the implementation of ‘noregrets’ policies — activities that make sense whether the seas rise or not. These include introducing salt-tolerant crops and dealing with the island’s highly visible trash problem. The process is painfully slow. It’s interesting to me because I’m not just an “anonymous internet user” as you claim. I am Willis Eschenbach, I have published on this topic, I know the players, I’ve seen the atolls, and I’m one of the scientists quoted in your citation … so at this point, you are the anonymous internet user. Their description of my position was good, except that they misrepresent my conclusion. They say > [@](#): > > Eschenbach, who carried on a spirited debate with Hunter in the journal Energy and Environment, has concluded that sea-level rise in Tuvalu is an illusion. He has used that conclusion to support an argument that there is no clear evidence for climate change. In fact, I did not say that sea level rise in Tuvalu is an “illusion”, that’s nonsense, there’s sea level rise everywhere. I concluded that a) there was no increase in sea level rise over the historical levels, as is shown by the other quotes above, and b) that the damage being done in Tuvalu is from erosion due to human-created changes in the reefs and islands, just as Webb says above. I made no argument about whether the Tuvalu situation was evidence for climate change, there’s no “evidence” there for either side. I also recommended the “no-regrets” types of actions that Webb has proposed, both in my article and to the US Ambassador to Tuvalu, who passed it on to the Tuvaluan Government. Kinda humorous, though … you go out to find an article to support your side, and you end up with an article quoting (and also mis-quoting) me … go figure. w. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [January 2, 2007, 8:02pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/106 "2007-01-02T20:02:06Z")
> [@intention](#): > > This is why I said that if emissions do not increase, the airborne amount will level off. The amount in the air at that time will be such that 3% of the airborne amount (the amount sequestered) will exactly equal our emissions. This will be on the order of 425 ppmv. Ah, perhaps I wasn’t clear enough with my question - _of course_ I believe that if we reduced our emission rate to the annual sequestration rate tomorrow, the CO2 concentration will level off at some point in the future. My question was, more specifically, will the sequestration rate increase _such that the annual increase in CO2 concentration will **start to fall** _? > [@](#): > > Sure, I’d be glad to take a bet on the question. Nothing makes me happier than a bet on a sure thing. My bet is that you’ll agree with me now that sequestration is increasing, no need to wait five years. I have put an excel spreadsheet with all of the data here so anyone can check my figures. Take a look at the data and you can tell me if sequestration is increasing as emissions have increased. If it is, I win the bet. If not, let me know what is wrong. I have included references to the data. Get back to me on this one, loser has to apologize to the other guy. No, let’s stick to the next five years’ data, and I’ll clarify the bet: The current rate of increase for CO2 ppm is over 2 ppm per year.[ul][li]I bet that it will continue to increase at, on average, over 2 ppm per year for each of the next five years. [/li][li]If it starts to fall below 2 ppm per year (or 2.1 ppm per year, or another level to be agreed upon – you can name your threshold since we might disagree on _precisely_ what the current rate of increase is), you win the bet. [/li][li]If we see an increase of _3 or more_ ppm per year, I win _big_.[/li][li] Loser to pay for a white T-Shirt printed with a message chosen by the winner in 3 inch bold black letters, to be worn in a busy public place, and a photograph of this to be posted on this message board.[/ul]Deal or no deal?[/li] And could you address my points about your incredibly optimistic choice of sensitivity and utter absence of time lags and positive feedback in your predictions given how little you say we know about climatology? > [@FRDE](#): > > I really can’t be bothered with this. Yes, I’m afraid it shows. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 2, 2007, 11:24pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/107 "2007-01-02T23:24:56Z")
[QUOTE=SentientMeat] Ah, perhaps I wasn’t clear enough with my question - _of course_ I believe that if we reduced our emission rate to the annual sequestration rate tomorrow, the CO2 concentration will level off at some point in the future. My question was, more specifically, will the sequestration rate increase _such that the annual increase in CO2 concentration will **start to fall** _? No, let’s stick to the next five years’ data, and I’ll clarify the bet: The current rate of increase for CO2 ppm is over 2 ppm per year.[ul][li]I bet that it will continue to increase at, on average, over 2 ppm per year for each of the next five years. [/li][li]If it starts to fall below 2 ppm per year (or 2.1 ppm per year, or another level to be agreed upon – you can name your threshold since we might disagree on _precisely_ what the current rate of increase is), you win the bet. [/li][li]If we see an increase of _3 or more_ ppm per year, I win _big_.[/li][li] Loser to pay for a white T-Shirt printed with a message chosen by the winner in 3 inch bold black letters, to be worn in a busy public place, and a photograph of this to be posted on this message board.[/ul]Deal or no deal?[/li] And could you address my points about your incredibly optimistic choice of sensitivity and utter absence of time lags and positive feedback in your predictions given how little you say we know about climatology? … [/QUOTE] Sentient, thanks for the post. This all started with your offer to bet on whether the amount of CO2 sequestered each year was rising, a claim you derided as being “faith-based” > [@SentientMeat](#): > > So, would you be willing to make a bet? If the amount of CO2 sequestered shows an average increase over the next five years, in line with your predicted miracle, I will lose the bet. If it stays the same, I win. (If it decreases, I win big!) I said, sure, we can settle it right now. I provided the [data](http://tinyurl.com/ybtv84) to do so. You reply that no, whoa, wait a minute, you don’t really want to bet on whether the amount of CO2 sequestered will rise as you clearly stated. You want to bet on whether the rate of atmospheric CO2 growth will increase above the current levels … While that is an interesting question, it is not what you offered to bet about. Does this mean that you’ve seen the light, that my claim that sequestration has been increasing is not “faith-based” but is hard scientific fact, that increasing sequestration is not a “miracle” as you claim but is actually happening? Finally, you say: > [@SentientMeat](#): > > And could you address my points about your incredibly optimistic choice of sensitivity and utter absence of time lags and positive feedback in your predictions given how little you say we know about climatology? Sorry I missed those, and the thread is too long to guess which points you are referring to. Please restate them, I’d be more than happy to discuss them. w. PS - you say: > [@SentientMeat](#): > > _of course_ I believe that if we reduced our emission rate to the annual sequestration rate tomorrow, the CO2 concentration will level off at some point in the future. That is not what I said. I said that if we _freeze our emissions rates at present day levels_, because of increasing sequestration, the CO2 concentration will level off at some point in the future. On the other hand, if we _reduce our emission rates to the annual sequestration rate_ tomorrow as you say, the CO2 concentration will level off immediately. Since by definition everything we are emitting is being sequestered, how could it do otherwise? ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 3, 2007, 12:38am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/108 "2007-01-03T00:38:01Z")
[QUOTE=intention] As I mentioned, this is a typical response of a system to disturbance, called an “exponential decay”. Consider the earth, and imagine that there are no disturbances. Then, one year, we add 30 Gtonnes of C to the atmosphere. Will it still be there in 1000 years? No, the amount in the air will gradually be reduced, year after year, until the original proportion is restored. … You ask “what is the mechanism”? It is the same mechanisms which have been operating since forever. One of the things about chemical reactions is that when you increase the concentration of one of the reagents, it drives the reaction in the other direction. Google “Le Chatelier’s Principle” for further information. [/QUOTE] **intention** : Your simple model invoking exponential decay and Le Chatelier’s Principle is way too simplistic. In the real world, there are many different processes with different decay rates that govern the uptake of CO2. I am not all that knowledgeable on carbon cycle modeling but the impression that I get is that there are many potential positive feedbacks that can come into play and do not bode well for the future. [Here](http://www.grida.no/climate/ipcc_tar/wg1/106.htm) is some discussion of future changes in ocean CO2 uptake. And, [here](http://www.grida.no/climate/ipcc_tar/wg1/103.htm#3227) is some discussion of constraints on terrestrial CO2 uptake. I am sure that the scientists who work in the field are familiar with Le Chatelier’s Principle and exponential decay and yet I am also pretty sure that their conclusions don’t generally agree with yours. (Feel free to demonstrate otherwise.) It is thus incumbent on you to explain why you are right and they are wrong. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 3, 2007, 12:58am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/109 "2007-01-03T00:58:56Z")
Along the lines of my last post, [here](http://www.grida.no/climate/ipcc_tar/wg1/096.htm) is some information from the summary of the IPCC chapter on the carbon cycle: > [@](#): > > There is sufficient uptake capacity in the ocean to incorporate 70 to 80% of foreseeable anthropogenic CO2 emissions to the atmosphere, this process takes centuries due to the rate of ocean mixing. As a result, even several centuries after emissions occurred, about a quarter of the increase in concentration caused by these emissions is still present in the atmosphere. CO2 stabilisation at 450, 650 or 1,000 ppm would require global anthropogenic CO2 emissions to drop below 1990 levels, within a few decades, about a century, or about two centuries respectively, and continue to steadily decrease thereafter. Stabilisation requires that net anthropogenic CO2 emissions ultimately decline to the level of persistent natural land and ocean sinks, which are expected to be small (\<0.2 PgC/yr). That seems to paint a very different picture than your simple model. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 3, 2007, 3:27am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/110 "2007-01-03T03:27:25Z")
[QUOTE=jshore] **intention** : Your simple model invoking exponential decay and Le Chatelier’s Principle is way too simplistic. In the real world, there are many different processes with different decay rates that govern the uptake of CO2. I am not all that knowledgeable on carbon cycle modeling but the impression that I get is that there are many potential positive feedbacks that can come into play and do not bode well for the future. [Here](http://www.grida.no/climate/ipcc_tar/wg1/106.htm) is some discussion of future changes in ocean CO2 uptake. And, [here](http://www.grida.no/climate/ipcc_tar/wg1/103.htm#3227) is some discussion of constraints on terrestrial CO2 uptake. I am sure that the scientists who work in the field are familiar with Le Chatelier’s Principle and exponential decay and yet I am also pretty sure that their conclusions don’t generally agree with yours. (Feel free to demonstrate otherwise.) It is thus incumbent on you to explain why you are right and they are wrong. [/QUOTE] Sure, be glad to, but since their conclusions do agree with mine, I don’t have to show they are wrong. As luck would have it, someone on a list I read cited a [study](http://www.stanford.edu/group/efmh/fossil/ClimRespUpdJGR%201.pdf) just today that is directly to the point, by Mark Jacobson of Stanford, the only climate modeler worth listening to. This paper is not about models, however, it is about the exponential decay of CO2 in the atmosphere. Note in particular Figure 2, which shows _ **exactly what I said** _. This was that if we freeze our emissions at the current rate, the atmospheric concentration will not rise indefinitely, but will level out well below 600 ppmv. (I had calculated that it would level out around 420 ppmv, Jacobson says 440 ppmv.) Note that there is no discussion in the paper about the fact of the exponential decay, that’s accepted science and not questioned, the discussion is about the speed of the decay. You derided this statement as “faith-based”, called it “miraculous”, and generally ridiculed me for making the claim … now that I have shown that it is accepted science, could you back off a bit on the abuse, and perhaps consider that your own opinions might not be as scientific as you think? w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 3, 2007, 3:32am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/111 "2007-01-03T03:32:49Z")
[QUOTE=jshore] Along the lines of my last post, [here](http://www.grida.no/climate/ipcc_tar/wg1/096.htm) is some information from the summary of the IPCC chapter on the carbon cycle: [quote] There is sufficient uptake capacity in the ocean to incorporate 70 to 80% of foreseeable anthropogenic CO2 emissions to the atmosphere, this process takes centuries due to the rate of ocean mixing. As a result, even several centuries after emissions occurred, about a quarter of the increase in concentration caused by these emissions is still present in the atmosphere. CO2 stabilisation at 450, 650 or 1,000 ppm would require global anthropogenic CO2 emissions to drop below 1990 levels, within a few decades, about a century, or about two centuries respectively, and continue to steadily decrease thereafter. Stabilisation requires that net anthropogenic CO2 emissions ultimately decline to the level of persistent natural land and ocean sinks, which are expected to be small (\<0.2 PgC/yr). > [@](#): > > That seems to paint a very different picture than your simple model. The problem with this is that the IPCC is using a very long residence time, up to 200 years, while the data gives a very different answer. See the Jacobson paper cited just above for a discussion of this issue. Also, stabilization does not require that emissions decline to 0 as they claim. Think about it and you’ll see why. Thanks, w. ---
**Author:** ![Hentor\_the\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/h/8edcca/32.png) [@Hentor\_the\_Barbarian](https://boards.straightdope.com/u/Hentor_the_Barbarian)\ **Post date:** [January 3, 2007, 4:56am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/112 "2007-01-03T04:56:54Z")
[QUOTE=Don26] Isn’t it the height of arrogance to think we can destroy the earth? [/QUOTE] The earth will be just fine. It will shrug us off like a leisure suit. Perhaps in the earth’s future, it will have some sort of nostalgia television show. Maybe even a whole series, with funny clips of remembrances from something very much like Mo Rocca. “Hey, Remember the Humans!” “I Loved the Dinosaurs!” Maybe it will have insults for other planets, like “Hey Saturn, the Time of the Humans called. It wants its hairstyle back!” It’s not arrogance to think that we can destroy ourselves, is it? ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 3, 2007, 6:24pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/113 "2007-01-03T18:24:10Z")
[QUOTE=intention] Note that there is no discussion in the paper about the fact of the exponential decay, that’s accepted science and not questioned, the discussion is about the speed of the decay. [/quote] It is not entirely clear to me that just because this is the assumption used in this paper, it means that it is accepted science that the decay can be approximated by a simple exponential. In fact, you want me to believe this one paper and then to ignore what the IPCC says, which represents a summary of the entire peer-reviewed literature. (Admittedly, the IPCC report is now a bit dated…So, it will be interesting to read the 4th assessment when it is released next month.) Anyway, I will try to look into this more when I have the time. I have never given much focus to the carbon cycle stuff. > [@](#): > > You derided this statement as “faith-based”, called it “miraculous”, and generally ridiculed me for making the claim … now that I have shown that it is accepted science, could you back off a bit on the abuse, and perhaps consider that your own opinions might not be as scientific as you think? Actually, you are attributing statements to me that were made by another poster. What I said is that you model is too simplistic as there are many different processes with different decay rates that govern the uptake of CO2. This is why the actual decay of CO2 levels back to their pre-industrial values (once we essentially cease our emissions) is not expected to be a simple exponential, but will have a long tail, as noted in IPCC report. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [January 3, 2007, 8:26pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/114 "2007-01-03T20:26:31Z")
**intention** , I apologise if my original offer of a bet wasn’t clear, which is why I clarified it. Just to be clear, are you refusing to bet on whether or not the annual CO2 concentration increase will fall or not? Here, I’ll point out a crucial phrase you seem to be blind to: > [@SentientMeat](#): > > So, would you be willing to make a bet? If the amount of CO2 sequestered shows an average increase over the next five years, **in line with your predicted miracle** , I will lose the bet. If it stays the same, I win. (If it decreases, I win big!) I wasn’t disputing your figures about more CO2 being sequestered every year, but about whether that would ever start to make a difference to the number which actually _matters_: the annual CO2 concentration increase. That’s why I clearly referred to what you miracle proposes: > [@SentientMeat](#): > > You admit that 3 gigatonnes of CO2 per year are not being absorbed, but pull from your hat the assumption that this number will start to decrease (presumably soon, ie. in the next decade or so?). Believe me, I wish for this miracle as strongly as you, but am so overwhelmed by skepticism (see, I’ve got plenty of it too!) that it merely seems so much wishful thinking. > > What is the actual mechanism of this vastly increased CO2 uptake? More plants, more plankton, more reflection of sunlight? Again, that would be wonderful. But it’s just not happening. Rainforests are being felled, phytoplankton is becoming less productive, white regions are melting to leave dark, methane-releasing regions. > > If your miracle doesn’t arrive within the next few decades, it might as well not bother turning up at all, so high will the concentrations be by then. And surely, given your hose analogy, the water can’t start filling up the barrel quicker, as though the increased pressure reduces the speed of the outflow. I hope we’re now both as clear as we can be about what the bet is. Again, just for clarification: Deal or no deal? > [@intention](#): > > Sorry I missed those, and the thread is too long to guess which points you are referring to. Please restate them, I’d be more than happy to discuss them. > [@SentientMeat](#): > > As for the “half a degree”, don’t you realise that you are hoisting yourself by your own petard? You are at great pains to emphasise that we _just don’t know_ how global climate works, and then adopt the absolute _most optimistic_ estimate for its sensitivity to increased CO2! This, to me, is as unreasonable as adopting the most _pessimistic_ estimates of 10 degrees or so - the figures we, both of us, roll our eyes when sensationalist news agencies use in their headlines. > > Also, don’t you think there might be a **time lag** , such that we haven’t yet seen all the warming effects of the 20th century’s emissions? As you say, repeatedly, we _just don’t know_ - we could merely be seeing the warming effects of the CO2 concentrations in the _1950’s_ or something. Measuring the temperature at midnight on 1/1/2000 and saying “See, half a degree!” smacks of legerdemain even to a layperson like me. You must admit, your prediction of sensitivity is way, _way_ up in the most optimistic clouds of cuckoo land. How do you square this with your repetition of just how clueless we are at predicting what will happen, since said uncertainty must surely admit the possibility of _worse_ case scenarios? > [@](#): > > That is not what I said. I said that if we freeze our emissions rates at present day levels, because of increasing sequestration, the CO2 concentration will level off at some point in the future. But Le Chatelier’s principle is for a reaction **in equilibrium** and, yet again, we _just don’t know_ whether the climate can be modelled so. You chided me for applying simple physics to a complex system and compared aluminium and a human body. Here _you_ are doing the every same! Yes, add ethanol to a simple chemical reaction and you’ll see an “opposition” to its increase in concentration. But keep giving uniform shots of whiskey to a _human being_ and the consequences are altogether different. (And if we know so little about climatology, we simply can’t say where the **saturation** point is, if anywhere. That’s why I wanted to explore the actual _mechanisms_ of CO2 sequestration, analogous to the statistically simple collisions in a beaker of solution). > [@](#): > > On the other hand, if we reduce our emission rates to the annual sequestration rate tomorrow as you say, the CO2 concentration will level off immediately. No, if we stopped emitting literally any more CO2 tomorrow, there would still be all those excess Gigatonnes from _last_ year, and they would _then_ begin to be sequestered at such and such a percentage per year. This is why I asked you why you seem to assume zero time lags in terms of release and effect. Those excess 86-53=33 Gt won’t disappear overnight, whatever we do tomorrow. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [January 3, 2007, 8:35pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/115 "2007-01-03T20:35:06Z")
**intention, FRDE, Leaffan** and others, I have to thank you. It takes a big man to admit this, but … you ready? I have [changed my mind](http://boards.straightdope.com/sdmb/showthread.php?t=402609). ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 3, 2007, 10:36pm UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/116 "2007-01-03T22:36:48Z")
By the way, a good general discussion regarding the fate of the CO2 that we release into the atmosphere is [this](http://www.realclimate.org/index.php/archives/2005/03/how-long-will-global-warming-last/) guest commentary by David Archer on the RealClimate website. [If you are allergic to RealClimate, then you can start with the reference section and go directly to the peer-reviewed literature it cites. 😉] It explains the mechanistic issues involved and the timescales associated with different processes. ---
**Author:** ![ITR\_champion](https://avatars.discourse-cdn.com/v4/letter/i/c67d28/32.png) [@ITR\_champion](https://boards.straightdope.com/u/ITR_champion)\ **Post date:** [January 4, 2007, 1:54am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/117 "2007-01-04T01:54:58Z")
So far we’ve covered three cases: Netherlands, Maldives, Tuvalu. In all three cases we’ve seen cites that waters are rising and some land has already been abandoned. Further in all three cases we’ve seen that this is a combination of global warming and local factors such as coral reef destruction. Now, _intention_, you keep wanting to emphasize that the local factors exist. Yes, I’ve never denied that they exist, but the point is that climate change is also a factor. Further, given the [accelerating melting](http://cires.colorado.edu/science/groups/steffen/greenland/melt2005/) in Greenland and [Antarctica](http://news.bbc.co.uk/2/hi/uk_news/4228411.stm), the rate of flooding resulting from climate change is guaranteed to accelerate in the near future. This discussion began when **Leaffan** asserted that global warming was a myth cooked up by a secret conspiracy of Marxists. I responded that the human race is currently abandoning some land because of rising sea levels. Pointing out that _some_ of the flooding comes from other factors doesn’t change my argument. As long as _some_ of the flooding comes from rising sea levels due to melting ice sheets, it’s useless to pretend that global warming isn’t happening. Of course, since **Leaffan** has run with his tail between his legs, the point is unnecessary. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 4, 2007, 3:03am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/118 "2007-01-04T03:03:11Z")
[QUOTE=SentientMeat] intention, I apologise if my original offer of a bet wasn’t clear, which is why I clarified it. Just to be clear, are you refusing to bet on whether or not the annual CO2 concentration increase will fall or not? Here, I’ll point out a crucial phrase you seem to be blind to: > [@](#): > > Originally Posted by SentientMeat > So, would you be willing to make a bet? If the amount of CO2 sequestered shows an average increase over the next five years, in line with your predicted miracle, I will lose the bet. If it stays the same, I win. (If it decreases, I win big!) I wasn’t disputing your figures about more CO2 being sequestered every year, but about whether that would ever start to make a difference to the number which actually matters: the annual CO2 concentration increase. That’s why I clearly referred to what you miracle proposes: Quote: > [@](#): > > Originally Posted by SentientMeat > You admit that 3 gigatonnes of CO2 per year are not being absorbed, but pull from your hat the assumption that this number will start to decrease (presumably soon, ie. in the next decade or so?). Believe me, I wish for this miracle as strongly as you, but am so overwhelmed by skepticism (see, I’ve got plenty of it too!) that it merely seems so much wishful thinking. > > What is the actual mechanism of this vastly increased CO2 uptake? More plants, more plankton, more reflection of sunlight? Again, that would be wonderful. But it’s just not happening. Rainforests are being felled, phytoplankton is becoming less productive, white regions are melting to leave dark, methane-releasing regions. > > If your miracle doesn’t arrive within the next few decades, it might as well not bother turning up at all, so high will the concentrations be by then. And surely, given your hose analogy, the water can’t start filling up the barrel quicker, as though the increased pressure reduces the speed of the outflow. I hope we’re now both as clear as we can be about what the bet is. Again, just for clarification: Deal or no deal? [/QUOTE] Hogwash. Your original bet offer was perfectly clear. You said “If the amount of CO2 sequestered shows an average increase over the next five years, in line with your predicted miracle, I will lose the bet.” Let me spell it out for you. If the amount of CO2 sequestered goes up, you lose the bet. Is it clear now? In fact, you are not willing to put your money where your mouth was. I said sure, I’ll take that bet, and now, you want to pretend it was not clear. CO2 sequestered goes up, you lose, it’s perfectly clear … but now that I’ve sent you the data and the references, ooops, you realized that CO2 sequestration has been increasing for the last 150 years … so now you want to whine about how you weren’t clear. Man up. Admit you were wrong, admit that the increasing sequestration has always made a difference in how much remains in the air. How could it not? w. PS - you say “You admit that 3 gigatonnes of CO2 per year are not being absorbed, but pull from your hat the assumption that this number will start to decrease (presumably soon, ie. in the next decade or so?).” Please provide me with a citation, I don’t recall ever saying anything of that nature. PPS - It seems that now you want to bet on something else, but unlike your previous bet offer, whatever you want to bet on isn’t clear at all. There’s no timeframe, there’s no specification of what’s being measured, there’s no baseline. Unlike your last bet offer, which was perfectly clear (if on average CO2 sequestration increases over the next five years, you lose), this one contains no specifics at all. ---
**Author:** ![pantom](https://avatars.discourse-cdn.com/v4/letter/p/34f0e0/32.png) [@pantom](https://boards.straightdope.com/u/pantom)\ **Post date:** [January 4, 2007, 4:18am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/119 "2007-01-04T04:18:23Z")
**jshore** : that commentary seems to ignore what would happen if deforestation stopped tomorrow and reforestation of large areas were to take place. Wouldn’t that suck a bunch of carbon out of the atmosphere, or am I mistaken in thinking this? ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [January 4, 2007, 6:24am UTC](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737/120 "2007-01-04T06:24:09Z")
[QUOTE=intention] This is why I said that if emissions do not increase, the airborne amount will level off. [/QUOTE] Even taking this as a given, that’s one hell of a condition that you set. Even with radical policies in place, I doubt that emissions will cease to increase any time soon. Though I’m provisionally convinced by your arguments, they seem rather irrelevant, since (from the data you provide) carbon emissions are increasing. It’s kind of pointless to talk about some equilibrium climate state with constant emissions, when they continue to increase at an accelerating rate. [Previous page](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737.md?page=5) [Next page](https://boards.straightdope.com/t/climate-change-in-our-lifetime/385737.md?page=7)