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Comments 48501 to 48550:

48501. mikeh1 at 10:14 AM on 18 February 2013
       There is no such thing as climate change denial
       

       Good to see that John's article has been reprinted in the The Age and is also currently the lead story in the Google News science section.

48502. Tom Curtis at 09:31 AM on 18 February 2013
       No alternative to atmospheric CO2 draw-down
       

       meb58 @30, mass is converved, but the atmosphere is not a closed system.  To better understand the relationship, consider the following chart of changes in O2 and CO2 concentratration between 1990 and 2000:

       

       (Source:  IPCC TAR, discussed in greater detail here.)

       The essential points are that after the combustion of fossil fuels, ocean and land uptake of CO2, and outgassing of O2 from the ocean, there is an increase of 15 ppmv of CO2, and a decrease of 33 ppmv of O2.  CO2 is heavier than O2, with a molar mass of 44 g/mole compared to 32 for O2.  The difference, due to the carbon atom, would represent an increase in atmospheric mass if the only change in concentration were due to combustion.  That is because the carbon was not part of the atmosphere before combustion.  Of course, combustion is not the only process, so the net change is proportional to ((15 * 44) - (33 * 32))/44, or a reduction of 9 times the molar mass of CO2 for every mole of CO2 added to the atmosphere.  That represents a reduction in mass of  19.2 Gigatonnes of mass for every 1 ppmv increase in CO2 concentration.  As the mass of the atmosphere is 5.137 Petatonnes (= 10^15), however, that represents less than 4 ten thousandths of one percent of the atmosphere's total mass.

       You will have noticed that there is not a 1/1 ratio between expected decrease in O2 and expected increase in CO2 in the above chart.  That, as previously mentioned is because of the combustion of hydrogen in hydrocarbons.  As previously mentioned (and again by Phillipe), this H2O precipitates out of the atmosphere, and does not add to atmospheric mass.  The total H2O in the atmosphere is increasing, but that is because of increased temperatures and is largely controlled by the temperature.

       The increase in H2O due to increased temperatures probably exceeds the loss due to combustion of fossil fuels, but only be a small margin as H2O is light (molar mass = 18 g/mole).  It does indeed increase the release of latent energy via precipitation which is a factor in changes in extreme weather events.  It also reduces the lapse rate (a negative feedback) and increases the greenhouse effect of water vapour (a stronger positive feecback).  Whether that adds up to "bang" is for you to decide, but overall it certainly makes the prospects for the future less inviting.

48503. dana1981 at 09:21 AM on 18 February 2013
       A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios
       

       Icarus @34 - yes, when I say equilibrium sensitivity, I refer to Charney fast-feedback sensitivity.  If you look at longer timescales, the picture is bleaker.  However, you never know what's going to happen in the future.  If we keep climate change in the manageable range this century, maybe we'll eventually be able to come up with a viable technology to extract and sequester CO2 from the atmosphere, in which case the longer timescale feedbacks could be avoided.  It's hard enough to project what's going to happen in the next century, so I tend to not try to go much beyond that.

       Composer @32 - 2°C above pre-industrial would put us outside the range of climate variation over the past million years or so, at least.  That's another good reason to try really hard not to pass that threshold.

48504. Icarus at 08:00 AM on 18 February 2013
       A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios
       

       Just to follow up on the comments about what should perhaps be called the Charney or fast feedback climate sensitivity (which I believe Dana is using in this excellent article) vs. the full 'Earth system sensitivity', Hansen derives the following from palaeoclimate studies:

       Fast feedback climate sensitivity is 0.75 ± 0.125°C/W/m² (3°C per doubling)

       Climate sensitivity including slow albedo feedback is 1.5°C/W/m² (6°C per doubling)

       Climate sensitivity including slow albedo feedback & non-CO2 GHGs is 2°C/W/m² (8°C per doubling)

       Climate sensitivity including all feedbacks between Holocene & ice-free state is ~2.4°C/W/m² (9.5°C per doubling).

       Hansen & Sato 2011

        

       The full feedbacks would take hundreds (thousands?) of years to be fully realised but studies find that we're going to see them already making a substantial impact within this century.  Just using the fast feedback climate sensitivity is understating the scale of the problem, I think.  If the timescales of longer term feedbacks are uncertain, that's all the more reason to make sure they're not forgotten in our eagerness to quantify the scale and timing of global warming.  Not a criticism of this article at all, just an observation.

48505. Jose_X at 06:04 AM on 18 February 2013
       There is no such thing as climate change denial
       

       >> The reason there's a consensus of scientists is because there's a consensus of evidence. But for some reason, none of the contrarians wanted to engage with that part (I can't imagine why not).
       
       In case you really didn't imagine why not, I do imagine at least this much:
       
       They generally are not scientists, so they don't read the research papers and frequently wouldn't understand good evidence and conclusions from bad ones. The evidence they "know" are overviews from various websites that use simplified arguments and very frequently cherry pick the data to help build out the narrative being sold.

       Understandably, led astray to see a limited and misleading portion of the elephant, many get angry and think climate scientists are doofs and/or dishonest in failing to see what "is" there.

48506. martin3818 at 05:58 AM on 18 February 2013
       Analysis of Greenland Ice Cores May Provide Glimpse into Climate's Future
       

       How so you determine the ice's altitude when it melted?

48507. idunno at 05:33 AM on 18 February 2013
       2013 SkS Weekly News Roundup #7
       

       I am also struck by the "Most Influential Paper" story; I was already vaguely familiar with the math through McKibben's work.

       It does seem to me that there is some hope for help here from a not-so obvious source: Wall Street. It seems to me that there are some pretty sound reasons for questioning the stock valuations of many energy-sector companies, based on this math.

       As Chomsky has pointed out, it is illegal in America, for the CEO or other employees of a publically quoted company to do anything other than to try to maximise the stock value of their company, and thus profit to shareholders. This then, is their agenda.

       I increasingly suspect that it is quite difficult for investors, getting their information from the WSJ, the FT or Forbes, inter-alia, to actually get full information on the risks asscociated with their investments in the energy sector. It is certainly the case, in my opinion, that the little of the WSJ's journalism that I have seen on the subject of energy and climate does them no credit, and does their readers no favours.

        In the political and economic climate that we now inhabit, I am beginning to suspect that ultimately, the markets will decide.

        

48508. william5331 at 05:24 AM on 18 February 2013
       Analysis of Greenland Ice Cores May Provide Glimpse into Climate's Future
       

       On the other hand, CO₂ levels are much higher now than during the Eemian so perhaps we will have melting of the West Antarctic ice sheet and much more of Greeland than during the Eemian.

48509. Rob Painting at 05:03 AM on 18 February 2013
       Ocean acidification: Some Winners, Many Losers
       

       Eric - It shouldn't surprise you to learn that Matt Ridley is wrong. The oceans are well saturated with calcium ions, so they are not a consideration. The concentration of calcium ions dissolved into the oceans only changes on geological timescales (typically millions of years) - hence the shift between aragonite and calcite seas over these long periods.

       It seems for many marine life the concentration (activity) of carbonate ions is the key because carbonate ions serve as one of the building blocks of the calcium carbonate (chalk) shell/skeleton. One of the reactions that takes place when extra CO2 is dissolved into the oceans is:

       

       Seawater currently favours the left-hand side of that equation, so adding CO2 to the oceans is actually decreasing the activity of carbonate ions, which in turn makes shell-building ever more energetically expensive. Decrease the carbonate ion concentration sufficiently (calcium carbonate undersaturation) and we end up with seawater that is physically corrosive to marine calcifiers.

       This corrosiveness is already occurring in the waters of the American Pacific Northwest where oyster larvae are now largely unable to survive in the wild, because they dissolve (Barton [2012]). The Antarctic is also seeing highly corrosive surface water too. See the photo below of a pteropod (sea butterfly) which was caught (alive) several years ago: 

       

48510. Eric Grimsrud at 02:50 AM on 18 February 2013
       Ocean acidification: Some Winners, Many Losers
       

       Sorry, I meant to say  because" average concentration of Ca++ in the oceans is much HIGHER than the sum of all carbonate, bicarbonate, and carbonic acid concentrations."  Thus according to Ridley, increasing the latter three would assist in CaCO3 formation.  

       (as we also know, of course, increased acidity serves to decrease the conc of carbonate ion relative to bicarbonate and carbonic acid - thus working against CaCO3 (s) formation -  an important point not mentioned by Ridley).

48511. Eric Grimsrud at 02:42 AM on 18 February 2013
       Ocean acidification: Some Winners, Many Losers
       

        

       I have a question.  I have heard that the oceans are under saturated by CaCO3 because the average concentration of Ca++ in the oceans is much lower than the sum of all carbonate, bicarbonate, and carbonic acid concentrations.  However,  when concerned with the solubility of the CaCO3 shells of living organisms, I would expect that the more relevant question is - is the sea water in the immediate vicinity of these living species saturated with respect to CaCO3?   If so, one would observe a gradient of Ca++ concentration as one moves from the region of shelled species out towards the depths am remote regions of the oceans.  Certainly such measurements have been made.    

        

       Note that Matt Ridley has suggested that increased atmospheric CO2 levels will actually facilitate the growth of CaCO3 shells (in his misnamed book, Realistic Optimist) - an argument that has meaning only if the sea water in the vicinity of shelled critters is not saturated w.r.t. CaCO3.   

        

       Any insight on this point would be apprecited.

        

48512. Bob Loblaw at 02:36 AM on 18 February 2013
       No alternative to atmospheric CO2 draw-down
       

       meb58:

       Note that this discussion of how increasing CO₂ cause changes in climate is starting to get off-topic for this thread. If you wish to continue some of these discussions, it would be a good idea to look for a more appropriate thread. Look through the View All Arguments link (beside the thermometer bulb at the top left section of page) to find places that discuss many topics. Any comments you place on any topic you find there will show up on the Comments page that everyone can access using the link in the menu bar under the main header, so it will be seen.

48513. Bob Loblaw at 02:28 AM on 18 February 2013
       No alternative to atmospheric CO2 draw-down
       

       Meb58@ 30: " What prevents that extra heat from escaping into space faster?"

       
       In essense, it does escape faster. A hotter atmosphere will lose energy faster, via increased emission of infrared (IR) radiation, but the followup to that is the question "at what point is a new balance reached?" A new balance is nto reached instantaneously - it takes time. If you want to think of it in a stepwise fashion, the steps are:

       a) energy, as sunlight, is absorbed by the earth-atmosphere system, mostly at the surface (but don't worry about that for now).

       b) energy is lost to space, from the earth and atmosphere, by IR radiation.

       c)  the earth-atmosphere system will be at equilibrium (i.e., a stable climate/temperature) when a) and b) balance.

       d) adding CO₂ to the atmosphere makes the process in b) less efficient (IR is less easily transfered through the atmopsphere), so b) decreases and a) is now greater than b).

       e) as long as a) is greater than b), the earth-atmosphere system accumulates energy, and will heat up.

       f) as the earth-atmosphere heats up, it will lose more IR to space (step b)), because hotter objects give off more IR.

       g) the system will continue to heat up until a) and b) balance again, which will be at a warmer temperature than it was before the extra CO₂ was added.

       An analogy would be a house with a fixed heater inside, and a fixed temperature outside. The heater will warm the house until the rate of heat loss matches the output of the heater. If you add insulation to the house walls (the equivalent of adding CO₂ to the atmosphere), the heat loss will initially decrease, and the house will start to warm up. As the house warms, the increased temperature difference between the inside and outside of the house will cause the heat loss from the house to increase, until it again matches the heater output. The hosue will no longer continue to warm, but the new stable temperature inside the house will be warmer than it was before you added the extra insulation.

48514. Philippe Chantreau at 02:15 AM on 18 February 2013
       No alternative to atmospheric CO2 draw-down
       

       meb58, the basic reaction is  CH + O2 -> CO2 + H2O

       I doubt that the mass of the atmosphere can vary in any significant way. Water vapor content is a function of atmospheric temperature, any excess will precipitate as liquid or solid water.

48515. Kevin C at 01:41 AM on 18 February 2013
       16 years - Update and Frequently Asked Questions
       

       KR: That's a good rigorous statement of the situation. Also well done for avoiding the null hypothesis fallacy, an easy mistake commonly made by people on both sides of the discussion.

48516. meb58 at 01:00 AM on 18 February 2013
       No alternative to atmospheric CO2 draw-down
       

       Tom Curtis,

       I missed what I think is an important detail in your #26 reply above.  I had not realized that the H2O was a by product of the combustion process, or perhaps forgot.  If I understand this correctly then would this extra H20 affect latent heat?  I see this extra H2O as water vapor...?  ...add more heat to more water vapor and bang!

48517. meb58 at 00:32 AM on 18 February 2013
       No alternative to atmospheric CO2 draw-down
       

       Tom curtis, Jose_X,

       Thank you very much!  Your explanations are very helpful.

       ...then, the consumption of O2 occures at the point of combustion?  And forgive my own intillectual density,  even though O2 is consumed to form CO2, doesn't the mass  of the atmosphere now stay the same following the law of conservation?  I am aware that my previous question was quite the opposite...your helpful descriptions are clearing up my own mis-conceptions.

       Still, in my conception of the atmosphere, I see an atmosphere that is growing hotter.  What prevents that extra heat from escaping into space faster?  I equate my question to this example.  Let's take a one square foot cube of steel heated to 150 deg F and place it in a room set at 0 deg F.  I suspect the heat loss will follow some particular and repeatable time frame until the two reach the same temperature.  I uderstand, I think, that the heat loss may be rapid in the beginning and slow as the two begin to reach equilibrium.  However, if we now add heat doesn't the steel block lose heat faster?  ...hmmm may have just answered my own question...the source of heat we are providing is increasing over time and over-runs the ability of our atmospher to dissipate the extra heat...?

       
       Thank you...I would love to go back to school and revisit physics and chemistry.

48518. chriskoz at 23:05 PM on 17 February 2013
       2013 SkS Weekly News Roundup #7
       

       Interesting recap of the history of Most Influential Climate Science Paper which is this paper. Evidently mostly quoted paper in the history of climate science, not because it describes some break-through but because it links the climate modeling to the future of fosil fuel industry.

       The interesting piece is, that according to the article, no skeptics nor FF industry have ever denied the numbers in the paper. Instead, they've critiqued that the paper and the activists supporting it "do not understand the economic reality that FF are needed as energy source". In other words, "we are so much dependant on FF, like a drug user that is doomed & must die, such paper does not change it". I can only make one comment here: to draw such conclusion, one must be in a very sickly state of mind...

       Moderator Response: [DB] It is relatively unknown than an openly-available copy of that paywalled paper can be found here.
48519. Jose_X at 17:05 PM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       meb58, I should also mention that hot->cold happens "unquestionably" only in the absence of work, but adding work changes the equation. Humans are engineering chemical reactions that, along with gravity, apply work to the atmosphere as we change its composition.
       
       Sorry, I am not being more mathematically precise, but the point is that we may need to understand these contributions if we wanted to accurately verify/analyze the Second Law of Thermo.
       
       [Wikipedia: "heat always flows spontaneously from regions of higher temperature to regions of lower temperature, and never the reverse, unless external work is performed on the system."]

48520. Jose_X at 16:46 PM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       I think CO2 has been used (laboratory level) as a source of fuel along with sunlight in a soup of some semiconductors and various organisms. This isn't sequestration +producing energy needs in a CO2 neutral process. This is 0 sequestration + producing energy by drawing down CO2... which has the same effect.

        

48521. Jose_X at 16:40 PM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       meb58, a higher temperature gradient is the result of changing the material across which the gradient exists into a new material that allows a higher gradient to exist. In other words, more CO2 makes the old atmosphere into a new one that has higher insulative properties. If we replace a thin coat with a thick one, we can have a higher gradient. A paradox would exist if the material remained the same material, but changing the composition of the atmosphere is de facto creating a new intermediate material between space and the earth's surface.

48522. Tom Curtis at 12:39 PM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       meb58 @25, CO2 concentration has only increased 110 parts per million by volume since the pre industrial era.  Further, that increase has been accompanied by a loss of oxygen.  Not only does each molecule of CO2 formed draw one molecule of O2 from the air, but much of the CO2 comes from hydrocarbons.  That means approximately (for oil and gas) for each molecule of CO2 formed, two molecules of O2 are lost to the atmosphere, to form 1 x CO2 plus 2 x H2O.  The H2O then precipitates out of the atmosphere for a net reduction.  Further, CO2 dissolves in water more easilly than does O2, so while nearly all the O2 consumed in the reactions is lost (a small part is made up by ocean outgassing), around 50% of the CO2 formed is then dissolved in the ocean.

       The net effect, if any, will be a reduction in pressure.  However, as we are talking about changes in atmospheric composition of about 0.01%, the effect is negligible.

48523. meb58 at 12:21 PM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       Hello all. I am not a research scientist but I have some basic knowledge of physics and chemistry.

       
       I have a question about th greenhouse affect from a heating and cooling perspective.  I understand the a hot body will give heat off or transfer heat to a cold body if it the hot body is hot enough - entropy?   I think that I also understand the concept of partial pressure and that as a gas heats up it expands. 

       As we add more co2 to the atmosphere are we not increasing the pressure of the lower atmosphere?  If so, I would expect to see extra heat from generated from pressure as well.  In addition, since space is so cold, why does this extra heat escape faster into ooutser space due to the increased temperature gradient?   I've read that our upper atmospher is cooling and constricting.  Does this effect  help to keep the heat at lower altitudes?  Does  gravity play a role on co2 here?

       Thank you in advance.

48524. Charles08537024 at 10:48 AM on 17 February 2013
       There is no such thing as climate change denial
       

       It has been gratifying to see how many have pointed out Mr. Taylor's egregious interpretations of the Lefsrud and Meyer study, including seeing the authors of the study politely but firmly insist his interpretation was erroneous. Taylor has tried this tactic before, most recently with his "analysis" of a suvey of members of the American Meteorological Society.

       The editors of Forbes should be aware that Mr. Taylor's articles are providing rich fodder for those of us in the academy who wish to teach our students how not to interpret science.

48525. Icarus at 08:16 AM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       @Ger, #21:  Very good point.  If we generated electricity from biomass, displacing fossil fuel combustion and producing biochar in the same process, that would be a significant contribution to carbon sequestration.

48526. Glenn Tamblyn at 07:55 AM on 17 February 2013
       There is no such thing as climate change denial
       Howdy Cara, welcome to SkS. Interesting and gratifying that the authors of the study actually posted a comment on Taylors post saying that he couldn't make the claims he has about their study. It was in the polite language of science but actually it was quite a slap down. And, a Forbes staffer, Alex Knapp posted a few hours ago, pointing out that the title of his article was misleading. Maybe Forbes might start to take an interest in the quality (not) of what Taylor is putting upon their site.
48527. william5331 at 06:59 AM on 17 February 2013
       There is no such thing as climate change denial
       

       As has been pointed out many times, consenses amongst scientists doesn't make it true.  There is an ever shrinking possibility that we have it wrong and this is simply a natural (not human) phenomenon.  However, even if the whole theory of climate change is in error, there are a lot of other reasons to cease our use of fossil fuels.

       http://mtkass.blogspot.co.nz/2010/10/forget-climate-change.html

48528. John Russell at 06:20 AM on 17 February 2013
       No alternative to atmospheric CO2 draw-down
       

       The issue of geoengineering raises an interesting conundrum. Acceptance that it's required means that advocates must believe that...

       1) Climate change is real and a threat to humanity.

       2) Concerted global action is required by the world's governments.

       3) CO₂ emissions incur a cost to society—a cost directly related to the price of countering their effect through geoengineering, as well as costs of dealing with the impacts of climate change (in other words; a huge amount).

       Given these factors it would be illogical to continue with 'business as usual' at the same time as adopting geoengineering measures, unless we can find a method of geoengineering that precisely removes the CO₂ that burning fossil fuels dumps in the atmosphere. In fact, given that—by winding up the climate warming 'flywheel'—we've put ourselves already well on course for at least 2^o of warming and several metres of sea level rise, we actulally need to remove all the additional carbon we've put into the atmosphere over the last 150 years or so, as well as any we will need to contnue putting in the atmosphere in the future: a big ask.

       So, overall, getting countries to all agree to geoengineering will only happen at the same time as they all wake up to the imperitive of stopping burning fossil fuels. We're still far away from any serious action, but it's clear that the two will both occur at the same moment. It will not be an either/or.       

        

48529. John Russell at 05:22 AM on 17 February 2013
       There is no such thing as climate change denial
       

       The phrase 'climate denial' is a perfectly acceptable shorthand for 'climate-change-related denial'.

       Those who choose to make an issue of it by being literal are usually seeking to deflect from the subject under discussion. In other words; if you can't argue the evidence, nit-pick about phraseology.   

48530. Ian Forrester at 05:03 AM on 17 February 2013
       There is no such thing as climate change denial
       

       It is amusing to see the comment right at the top of the page as you open the Forbes site:

       Forbes Thought of the Day

       " Let a man practice the profession which he best knows. ”

       — Cicero

       It is obvious which profession Taylor belongs to.

48531. Clyde at 05:02 AM on 17 February 2013
       There is no such thing as climate change denial
       
       Tom Curtis - 5
        
       The perceived discrepancy is because John takes the average over 16 years, while Dana contrasts the endpoints of a 15 year interval.
        
        
       Thanks for the prompt & cordial reply.
48532. shoyemore at 03:43 AM on 17 February 2013
       There is no such thing as climate change denial
       

       Cara #8,

       Mark Hoofnagle on the denialism blog has a good takedown of James Taylor. The paper Taylor reports on contains these statements:

       First and foremost, our study is not a representative survey. Although our data set is large and diverse enough for our research questions, it cannot be used for generalizations such as “respondents believe …” or “scientists don’t believe …”

       In addition, even within the confines of our non-representative data set, the interpretation that a majority of the respondents believe that nature is the primary cause of global warming is simply not correct.

       http://scienceblogs.com/denialism/2013/02/15/denialism-from-forbes-courtesy-of-heartland-hack-james-taylor/

48533. Cara Hernandez at 02:13 AM on 17 February 2013
       There is no such thing as climate change denial
       

       "Consequently, a key strategy of opponents of climate action for over 20 years has been to cast doubt on the scientific consensus and maintain the consensus gap."

       
       As a recent example of this, please see the Forbes editorial written by James Taylor of the Heartland Institute, posted this week and entitled "Peer-Reviewed Survey Finds Majority Of Scientists Skeptical Of Global Warming Crisis."

48534. Dikran Marsupial at 00:59 AM on 17 February 2013
       We're heading into an ice age
       

       Tom, yes you are absolutely right about the cause of the decline in European populations, doh!  The info on English wine growing was also very interesting, ISTR there is something about it in the book on the British Climate compiled a few years ago, I think in honour of Hubert Lamb, but it is back in the library now, so I can't check. I hope Kevin learns from this exercise that perhaps his information on the topic of climate isn't perhaps all it could be, and will moderate the attitude in his posts somewhat.  We are all happy to discuss science here, but generally those who arrive with a bit of an attitude tend to provoke a correspondingly confrontational response.

48535. funglestrumpet at 00:34 AM on 17 February 2013
       There is no such thing as climate change denial
       

        

       It is a shame that this article falls for the manipulation of public opinion that has been so successful in branding all conspiracy theorists as somehow lacking the intellect to see the mainstream or official line on a topic. This is especially so when one considers the discrepancy between the scientific consensus and public support for action on climate change. Something close to the hearts of all who post articles here and the vast majority of those who comment on them I assume.

        

       I have always tried to follow the science of any issue that I choose to take an opinion on. That is as true of my stance on climate change as it is on 9/11. When someone can show me that climate change is not going to be a major problem by reference to the science, I might change my opinion. But there is a lot of evidence to contradict before I do so. Until then, I will campaign for the need to act and act now, if not sooner.

        

       Similarly, (-snip-).

        

       Moderator Response: [DB] Off-topic snipped.
48536. Richard D at 19:57 PM on 16 February 2013
       There is no such thing as climate change denial
       

       use of language plays some havoc in these situations. It's natural for people to use short hand of one form or another. So climate change denial is short hand for rejection of the consensus view of the social problem created by emissions of GHGs. Unfortunately that gives disinformationists room to play on the ambiguity of meaning. But this isn't really any different when some people say scientiic theory X (e.g. general relativity) can't be 'proven'. The word prove has different associations depending on who is saying it and what the context is.

48537. Rob Painting at 19:37 PM on 16 February 2013
       A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios
       

       Composer99 - the current rate of CO2 rise is unparalleled in the last 300 million years. See Honisch (2012). I've almost finished a post on Foster & Rohling (2013), but based on their research, global warming and consequent sea level rise will persist for many centuries. With atmospheric CO2 levels between 300-400 ppm (parts per million) sea level in the last 40 million years typically reached around 24 metres (+7/-15) higher than today. With CO2 now over 390ppm long-term sea level rise from greenhouse gases already emitted is going to be substantial.

       If the low climate sensitivity people are right, it implies extraordinary sensitivity of global land-based ice to small amounts of warming. I doubt they are right, but the basis for this is too lengthy to fit into a comment. Even keeping under the 2°C limit effectively dooms the coral reefs. A collapse of that ecosystem is going to have profound effects on the hundreds of millions of people whom depend on the reefs for protein. This will have significant repercussions for all humanity, especially so when industrial fishing methods are simultaneously emptying the oceans of fish. The future is going to very different to how many people imagine it will be. And not in a good way.

48538. Tom Curtis at 18:11 PM on 16 February 2013
       There is no such thing as climate change denial
       

       Clyde @4, from Nucitelli et al, 2012, Table 1 the average increase in heat at the Earth's surface from 2002 - 2008  was 0.73 W/m^2.  In contrast, the average heat accumulation from 1990 to 2008 was 0.46 W/m^2.  Clearly for those figures to make sense, the heat gain from 1990-2002 must have averaged 0.3 W/m^2.  The perceived discrepancy is because John takes the average over 16 years, while Dana contrasts the endpoints of a 15 year interval.

48539. Clyde at 16:49 PM on 16 February 2013
       There is no such thing as climate change denial
       
       Importantly, it also ignores the fact that over the last 16 years, our planet has been building up heat at a rate of over three Hiroshima bombs worth of energy every second. To deny global warming is to deny the basic fact that our planet is building up heat at an extraordinary rate.
       
       
       From <a href="

       http://www.skepticalscience.com/dueling-scientists-oregonian.html

       dana1981's"></a> article it says -
       
       
       
       
       

       In fact, heat is accumulating in the Earth's climate system due to the increased greenhouse effect at a faster rate today than it was 15 years ago, and the energy is equivalent to detonating four Hiroshima atomic bombs per second, every second over the past 15 years.
       

       
       

       Which is it 3 or 4? When you consider their detonating every second that makes a difference.
       
       
       
48540. Ger at 16:33 PM on 16 February 2013
       No alternative to atmospheric CO2 draw-down
       

       https://fortress.wa.gov/ecy/publications/summarypages/1107017.html for nice overview on the advantages of re-instating a clean charcoal industry based on biomass residues.

48541. Ger at 16:20 PM on 16 February 2013
       No alternative to atmospheric CO2 draw-down
       

       @#12, Icarus. Charcoal making does produce a lot of excess energy. Most retorts use the excess energy for producing steam. Pelletizing the charcoal dust from biomass residues takes a lot less energy than raw biomass, another energy saver. 

48542. Composer99 at 13:19 PM on 16 February 2013
       A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios
       

       With regards to the best vs worst-case scenarios, I'm curious how they stack up against paleo evidence.

       The danger limit agreed upon by policymakers is 2°C increase compared to pre-industrial times.

       Basically, apart from the best-case emissions scenario combined with best-case sensitivity, we can look forward to a minimum 2° increase, pretty much no matter what, by the end of the century.

       As far as I can see, a 2°C change in global mean temperature in approximately 250 years is almost without precedent in the period for which we have any remotely reliable paleoclimate data, that is, the past 550-600 million years.

       The only episodes I can think of with climate changes that are comparably rapid are the end-Permian and end-Cretaceous periods. So even the change that is considered under the danger limit involves the climate changing at a rate that is only seen in entirely undesirable circumstances, at least as far as I can see.

       But I'm a musician: anyone who knows this stuff care to comment?

48543. Jonas at 11:18 AM on 16 February 2013
       There is no such thing as climate change denial
       

       @Composer99: In self-perceived critical movements, I dislike the non scientific bias towards criticism (sometimes leading to esoteric or unscientific conclusions and sometimes even climate change denial). On the other hand, I do not like uncritical belief of science, if the source of the money and along with it the research goals and limitations are clear: being skeptical is especially useful, if research is driven by big business, as is the case for GMOs (no checks due to revlving doors legislation) and pharmaceutical products ...

       So, I am a science skeptic and especially a climate skeptic, but I did not find anything to complain about in climate science, up to now: it's not business driven (view the oil company benefits and you see where the majority of the money interests are), it's independent, open, scrutinized, multinational. But I remain skeptic on genetic engineering and pharmaceuticals   and I have (non scientific) reasons to remain so, because business is at least partially involved in what is researched.

       ---

       @Initial (re)post: I agree: I am not a climate scientist, but I read a lot on it, including books on climate science (currently blackbody radiation and placks law, phew!), but I try to communicate the scientific consensus, and I can see all sorts of excuses for not wanting to change, which all boil down to one of the top 10 arguments of denial listed in Sks, which basically go back to the genuine, independent scientific consensus. This is why I absolutely like the scientific guide to global warming skepticism, which draws a complete model of reality and points to the failure of skptics of having a consistent model of reality and the escalator graphics, which brings at least questionmarks into peoples minds who are unwilling to read the 12 pages they don't like ... This is a "constructive" approach, together with real life examples that communicate that even a big change need not be a loss in quality of life, only a change in habits, with a hard transition period, we all know that. 

       But I think we also need to cover who brings in the money to deny science consensus: http://www.pbs.org/wgbh/pages/frontline/climate-of-doubt

       Also, the former tobacco harm deniers are now in the climate denial business, e.g.
       http://www.sourcewatch.org/index.php/S._Fred_Singer

       Apparently, it 's the same strategy over and over again ...

48544. mikeh1 at 11:03 AM on 16 February 2013
       There is no such thing as climate change denial
       

       I prefer the term "climate science denial" over "climate change denial" for the reason that John outlines in the first paragraph.

48545. Composer99 at 10:56 AM on 16 February 2013
       We're heading into an ice age
       

       Kevin pretty much scored an own goal here.

48546. saileshrao at 09:56 AM on 16 February 2013
       No alternative to atmospheric CO2 draw-down
       

       @Daniel Bailey (15), please see, e.g., http://www.cosmosmagazine.com/news/forests-soak-third-fossil-fuel-emissions/ 

       Moderator Response: [DB] Thank you.
48547. sidd at 08:51 AM on 16 February 2013
       A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios
       That link to the new dataset for greenland bedrock seems to be garbled. The correct link should behttp://www.the-cryosphere-discuss.net/6/4829/2012/
48548. Farmer Dave at 08:17 AM on 16 February 2013
       No alternative to atmospheric CO2 draw-down
       

       Icarus @12: You may be excessively gloomy about the potential for CO₂ sequestration via biochar. An Australian company, Pacific Pyrolysis has developed a slow pyrolysis technology which (so they claim) takes an incoming biomass waste stream and converts about half of its carbon content to biochar. The other half is more than enough to drive the process (no need for fossil fuels after startup) and generates enough electricity to export a surplus from the plant. More information is available here.

       It's true that I am not aware of any independent verification of Pacific Pyrolysis's claims, and a full life cycle analysis would have to include fossil fuels burned during the aggregation and transport of the waste to the pyrolysis plant; however, pyrolysing waste which would otherwise be burned or allowed to rot would seem to be positive.

48549. sidd at 08:09 AM on 16 February 2013
       A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios
       The Greenland image was constructed from the Bamber data. There is a better dataset than Bamber these days.see www.the-cryosphere-discuss.net/6/4829/2012/Griggs et al.As far as abrupt melt goes, how are you going to get a mole of Joules into the ice ? sidd
48550. Tom Curtis at 08:03 AM on 16 February 2013
       We're heading into an ice age
       

       Dikran Marsupial @291, the very sharp decline in population in the 14th century has almost nothing to do with climate, and everything to do with the Bubonic Plague.  Much of the increase before that had little to do with climate, and much to do with the adoption of the horse collar in Europe.

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