Two degrees of warming

Now that it looks as if some sort of agreement may come out of Copenhagen, its natural to ask what sort of agreement we need. The current targets being proposed suggest that warming should be limited to 2 degrees over the next century. That implies stabilising atmospheric C2 concentrations at 450 ppm, and an agreement to cut developed country emissions by 20-25 per cent by 2020, with convergence to a level 90 per cent below current developed country levels by 2050 would be adequate (note that this part of the post is based on my reading of Garnaut, Stern & IIPCC, not my own expertise).

At least some discussion in Australia suggests that these targets are hopelessly weak and by implication that it would be better to oppose any action than to lock ourselves into an agreement of this kind. I disagree, and I will try to spell out why.

First up, as in other debates about climate change, it is important to pay attention to the science, rather than to rely on prejudice or on supposed authorities who are either unqualified or whose qualifications aren:t relevant. Thats why I have refused to debate climate science delusionists here, instead pointing them to the results of scientific research, summarised by the IPCC and other bodies.

But the case here is a bit different. The big impacts of climate change will be on agricultural production and natural environments and the relevant experts are ag scientists/economists and ecologists. The views of climate scientists like James Hansen, while very important in projecting the climatic effects of CO2 emissions, have no particular standing when it comes to assessing the damage associated with any particular climatic change.

As regards the ag economics, I am an expert, and am therefore happy to explain my position and discuss it with readers. I will add some links later, but for the moment Ill ask you to take statements of fact on trust that Ive done the work to verify them

What matters for agriculture is not so much the ultimate change in average temperature and rainfall, but the pace of change. Agriculture is undertaken in a wide range of climates, so there are very few places where an extra couple of degrees will make farming impossible. What changes in temperature and even more changes in rainfall will do is change the kind of crops that can be grown in any given location. Some areas will be more productive, and some less so, but, in the long run these effects will mostly cancel out. For a change of more than 2 degrees, the negatives predominate and they become overwhelming after about 4 degrees.

As regards the pace of change, 2 degrees warming over a century implies 0.2 degrees per decade on average which is like shifting the climate about 100 km closer to the equator each decade. That involves some costs, but they are probably manageable.

If agriculture can handle 2 degrees of warming, it seems likely that most human activities will do so. So, as far as human activity is concerned, it makes sense to target 2 degrees of warming as a reasonably conservative choice.

If you want to justify a target lower than 2 degrees, it has to rely on concerns about ecological damage and loss of biodiversity. There is no doubt that 2 degrees of warming will do a lot of damage, for example to coral reefs. But quite a few of the ecologists I talk to are at least as concerned about the immediate threats to biodiversity (in the case of coral reefs, these include overfishing, destructive fishing methods and nutrient runoff) as about the current rate of climate change. As the IPCC shows, business as usual would be disastrous. But the difference between 1 and 2 degrees of warming is probably less than the difference between sustainable and unsustainable choices in industries like fishing and forestry, and we could make a lot of progress on the latter issues at very modest costs.

Obviously, you can always push for a more ambitious target at higher cost. But the costs accelerate pretty quickly once you aim below 450 ppm. So, people advocating more ambitious targets ought to say how much they would be willing to pay and what they would give up.

54 thoughts on “Two degrees of warming

  1. The long-run equilibrium sea level rise from 2C would probably be pretty bad for human activity unless the US, Australia etc. are willing to take in millions of Bangladeshi etc. climate refugees.

  2. A binding target can be looked at from a couple of perspectives. Firstly even if it is doable it doesn’t necessarily imply merely ‘mild warming’. It could mean more severe droughts, floods, heatwaves, wind storms, rain interrupted harvests, summer frosts and so on. We’ve already had that with less than one degree. Secondly the key players could commit to targets but find themselves impotent in achieving them. In Australia’s case it almost beggars belief that sacred cows like the aluminium industry not only scuttled the ETS but now insist that the RET be adjusted lest they suffer any mild inconvenience.

    On top of human frailties Mother Earth could have her own ideas. I see in today’s Energy Bulletin that some think China’s coal production could nosedive as early as five years time. The IPCC need to rework their projections to include revised emissions scenarios.

  3. “If you want to justify a target lower than 2 degrees, it has to rely on concerns about ecological damage and loss of biodiversity.”

    John, this is incorrect. From attending the Climate Change Congress in Copenhagen this March, where 2-3 thousand scientists (including of the social sciences) presented the latest CC research and presented a summary to the Danish PM, a key message was that 2 degrees should not be considered a target: 2 degrees is what the scientist are telling us is an upper limit of acceptable risk.

    The crux of the matter is that scientists don’t know what will happen to ecological systems given a global aggregate of 2 degrees rise. There is some consensus that the system has a decent chance of holding together if we keep the change to no more than 2 degrees. But there is also fairly strong and widely shared concern that going over 2 degrees makes the risks of threshold effects unacceptably high.

    In climate change, threshold effects are the big problem. It may be that we permanently change the ecological equilibrium in a way that renders uninhabitable areas that are currently populated by tens of millions of (mostly poor) people.

    Disease vectors and water supply are two examples of how this may happen. South Asia (especially Bangladesh), and parts of China dependent on water sources from the Himalays along with North Africa (exhibit the conflict over water resources going on currently) are key risk points.

    Because of this excessive non-linearity in the probability of different cost/benefit combinations, climate change policy should not be informed by standard approaches to expected utility.

    Coming back to justifying targets lower than 2 degrees, this can be justified on the basis of different perceptions of acceptable risk profiles. An analogy presented in Copenhagen in March: 2 degrees gives us an 80 percent chance of avoiding catastrophic consequences. Russian Roulette gives an 83.3 percent chance. Hands up if you want to play.

    Having said all that, I think 2 degrees is where we should go right now because there has been major political will generated toward that. Changing the goalposts now would needlessly hamstring the effort to deal with all this: we can aim for tighter restrictions later. Right now there is urgent need for action and the first steps wont be dependent on the difference between a goal of 2 degrees by 2050 or 1.5 degrees.

  4. I am one of those who advocates a more ambitious target and I would, as a starting point, be prepared to pay whatever it takes for a fair system to work.

    The thing is, the initial costs would be quickly mitigated by action to reduce them. The tougher the better, as long as the poor were assisted.

    Efficiency measures cost initially but save money in the long term. If US oranges, Turkish apricots, NZ cheese, Chinese manufactured crap and Vietnamese fish cost more, fantastic. If it hurts, the freeloaders are likely to come under more pressure to do their bit. Beef producers will look harder to technology or another animal to farm. There will be an outcry to end logging of native forests and demands for transport efficiency mandates.

    The other thing we need to remember is that the consequences of the current GHG levels seem to be accelerating as the ocean and forests increasingly struggle to absorb the excess emissions. The forests just not there anymore. In other words, it looks to me that, even if we stopped emissions increasing now, the consequences would continue to intensify for some time.

    This is why I believe 450ppm is unacceptable.

  5. On the technology front I do think loads more people need to take a serious look at the Integral Fast Reactor. In essence it is a device that:-

    1. Takes large volumes of the worlds existing nuclear waste which otherwise needs to be carefully managed for long epochs of time and converts it into small volumes of nuclear waste that needs to be carefully managed for comparably small amounts of time.

    2. Has an inherently safe design (ie shuts itself down passively in the event of an accident).

    3. Could theoretically power the entire planet at the current rate of electricity consumption for about 700 years using nothing more than existing stockpiles of nuclear waste. In other words no need to mine new uranium at all.

    4. Is expected to create electricity at a price point lower than existing fossil fuel systems.

  6. Obviously, you can always push for a more ambitious target at higher cost. But the costs accelerate pretty quickly once you aim below 450 ppm.

    A carbon tax would make the cost quite explicit and as such I think it would allow us to arrive at a more democratic decision about the cost we are willing to wear.

  7. An important question is what likelihood would one tolerate of exceeding a particular temperature threshold, such as 2 degrees. A very good paper by Meinshausen et al came out in Nature earlier this year that estimated likelihoods of exceeding 2 degrees for various global emissions budgets for the period 2000-2050.

    Today I read a paper Schmidt et al (2009) Climate Targets in an Uncertain World that looked at policy implications of some of the uncertainties in things like climate sensitivity (the amount of average global warming from a doubling of CO2 levels). It does some cost effectiveness analysis (which I understand to mean constrained optimisation) to examine the question of how much should we reduce emissions now if we won’t find out how much warming we will get until a later date (e.g. 2030), when the trajectory is adjusted accordingly. My understanding from having a quick read of the paper is that we are better off starting with an initial trajectory that is similar to what we would follow if we expected climate sensitivity to be very bad.

    I therefore think that it would be optimal if current emission reductions were consistent with a very high probability of staying under 2 degrees. If my electricity costs quadrupled in order to achieve this then I would accept that without hesitation. Unfortunately because of political barriers and difficulties with international cooperation we are likely to go on an overshoot trajectory instead.

  8. John,

    it’s more complicated than that. To get to 450 or lower, an overshoot is required probably past 500 then back. This implies accelerating rates higher than your 0.2C per decade in the first half of the century, even if climate was linear which it is not. The chance of triggering positive feedbacks increases. The risk of exceeding 2C pre-industrial at these levels is worse than 50/50. Non-linear changes at regional scale are highly likely, and this has laready been experienced in SE Australia, where the past 12 years has been equivalent to the worst case projections for 2030-50. The projections are the smoothed signals from the models encompassing uncertainty – the Earth is a bumpy ride, as each of the climate model runs attests. While I think ag in Australia can adjust to these changes because of our capacity, there is much more besides. Canberra is already running triage on parts of northern Victoria because of water already lost from the system but have failed to inform the locals of that decision.

    Ecosystems will change with some delay in response to extreme events. What the systems in SE Australia will do in response to the already observed changes is worrying. Through the century how much more deterioration might we experience? Fires and water supply in our forested catchments, if following recent patterns, will be catastrophic in some areas.

    It’s not just Australia. These changes also need to be considered for the big transnational catchments such as the Mekong, Tigris/Euphrates, Nile and Ganges/Brahmaputra. Climate change is not the only issue – food security, population, power and water supply combine to increase risks of destabilisation.

    The last time the Earth’s climate was at 450 ppm for an extended period there was no West Antarctice Ice Sheet. We’re referring to 10-12 m sea level rise here. Even if the 21st century rise was restricted to 1.4C, making up 2C total, over the next few hundred years the further changes would be inexorable without further reductions.

    If Australia was the only place of concern, your argument might stand up. While making some really good points I don’t think it survives the bigger picture. And if the overshoot point is the critical medium term point to get to, I don’t have to declare how far down the other side we need to go now, better to get to that point (close to 500 CO2 equivalent as possible, on the downside and by 2050 if possible) and survey the view on the other side with a great deal more knowledge than we have now. I suspect a low carbon economy at that stage would have less trouble with the costs than we seem to have now, for many reasons.

    One of the major problems is that climate policy is presently treated as an equilibrium problem. It’s not, it is a complex system, or wicked, problem and should be treated dynamically in a risk management sense where knowledge is being gained from research, from observation and from agency, not as a prediction-response issue. Declaring how much one would have to pay now beyond the overshoot point is silly if one wants less than 500 ppm CO2e, because 500, frankly, is dangerous.

  9. Roger, I agree with what you say about overshooting, and with much of the rest of your comments. I think it’s highly likely that, if we get an agreement on cuts now based around a 2 degree target, it will entail overshooting and therefore negative net emissions after 2050. Given progress in achieving a low carbon economy using existing and new technologies this ought to be feasible at relatively low cost. I’m more concerned with responding to arguments that we need a full-scale emergency response now and that anything less is a waste of time.

  10. John, adapting to sustainable development will bring new technologies online which can only benefit mankind and I believe a target of between 25%-40% is achievable. The benefits and savings from innovative solutions means a lot of waste byproducts now being discarded will eventually all be recycled and business need to adapt to the new way of life like Southwest Airlines’ Dallas and Houston operations in the US which purchase approximately 16 million kilowatt-hours of green power to meet 30 percent of their electricity needs from use Reliant Energy.

  11. On theories, there is theoretically no reason for third world poverty. Stick that in your Integral fast reactor and see what you come up with 😉

  12. The focus is upon CO2e ppm in the atmosphere, but we have to realise that CO2e ppm is a highly stylised representation of the combined human impact upon the environment; in many ways, it is quite a misleading metric. For example, let’s say we all took a year off from emitting CO2e, and went to the beach. What is the CO2e ppm going to be at the end of that year? The same as last year? Almost certainly not. And thus, as a control variable in a control problem, just tracking our annual CO2e contribution is not enough to describe the path in terms of control, or the trajectory in state space of the climate system. Add in various sources of stochastic variables which demonstrably affect the climate system, and it is clear enough that we had better err on the side of caution in the way we approach 450ppm, 500ppm, or whatever target is set. CO2e ppm is neither an integrated control or a state variable; it is some mixture of both. The focus has been on it as though it is a (reversible) control variable, and that is a category mistake.

    Alternatively, look at the tuple (T, A), where T = temperature in degrees Kelvin/Celsius/Fahrenheit, and A is the amount in gigatonnes (ie billion tonnes) of greenhouse gases (GHGs) in the atmosphere. Let’s instantaneously dump an amount of G GHGs into the atmosphere: the new state of the simplistic climate system is described by (T, A + G), say (T’, A’), where T’ = T and A’ = A + G. Let things settle for a bit – perhaps we’ve collectively gone to the beach – and during the interim the system migrates to (T”, A”), where T” = T’ + dT’, A” = A’ + dA’ say. Let’s assume that dT’ > 0 so that the temperature increases.

    If T” is too hot for us on the beach, and we want to go back to the pleasant T degrees it was before, what might we do? We could try subtracting the difference D = A” – A to get the total GHGs back to where we started. This puts us in the new state (T”, A) =/= (T, A). We go back to the beach with our suncream SPF 2000, and wait for the temperature T” to drop down to T again. Only it doesn’t, because the system a) is not completely represented by T and A variables alone; and b) the system as represented by (T, A) variables is not reversible, either as a purely dynamical system, or as a thermodynamic system.

    Perhaps we end up at (T”’, A”’) where both T”’ > T” and A”’ > A” and that would be terrible! The upshot is, even for a deterministic system, the danger of thinking purely in terms of increases of greenhouse gases driving global mean temperature changes is that we then fall into the trap of falsely reasoning that decreasing emissions of GHG will decrease global mean temperatures. But it won’t necessarily!
    Even if (T, A) was a faithful representation of the climate system and even if in addition, the climate system was deterministic, that is not sufficient to rule out hysteresis effects, for example.

    Furthermore, in Australia if we split rural areas into areas which are drought declared or exceptional circumstances, and those which are not – say DX = “drought declared or exceptional circumstances”, and NM = “normal conditions”, then the ratio DX/NM is typically way above 1. In other words, being drought declared or listed as exceptional circumstances is more common than being in the so-called normal conditions. Now the Australian environment is such that if global mean temperature goes up, we will have many more extreme temperature days ( ie 40C or above) and extreme nights (ie 30C or above). Most plants shut up shop once daytime temperatures exceed 40C or thereabouts – some trees only stop stomatal evaporation once they’ve had around three days of extreme nights and/or extreme days. Many other plants simply wilt and die if they cop two or three extreme days followed by extreme nights.
    Therefore, an increase of just one degree Celcius might be enough to cause radical growth of non-arable land, and a significant decrease in vegetative cover. Of course, every degree above 40C causes a sharp increase in water-way and dam evaporation too. These changes are unlikely to be reversed just by removing GHGs from the atmosphere again; much simpler not to put the gases there in the first place.

  13. JQ’s ‘something is better than nothing’ approach (SBN) misses the point in my view. As Donald points out, and just looking at climate and greenhouse, we are influencing a classic nonlinear system of feedback with delays. We don’t, and cannot, know the consequences of the effects. Furthermore, SBN increases our uncertainty of the future rather than decreases it. A mistake could be fatal for any number of people up to and including billions. The only rational approach that includes caring for human life as a primary goal is radical and rapid reduction in greenhouse output. The idea that this is too expensive is ludicrous unless one accepts that current spending priorities are natural, essential and inviolable, and environmental protection is somehow an ‘added extra’

  14. jquiggin :
    I’m more concerned with responding to arguments that we need a full-scale emergency response now and that anything less is a waste of time.

    I agree. I’m not a climate scientist or an economist, but I can see that even a weak scheme will set the ball-rolling on new clean technology investments and reduce investments in carbon polluting industries. The amount of mitigation currently going on in Australia is miniscule. The majority of the population hasn’t even taken the first step and saved themselves money by reducing wasted energy consumption. The whole debate hasn’t made any discernible impact at all on most peoples lifestyles. So almost anything would be better than the present do-nothing situtation. In fact one could make the argument that business as usual is accelerating the rate of emissions growth.

  15. I realise I left out something from my post. SBN functions to increase delay in the system. By taking SBN as a serious option we trivialise the problem by centering and implicitly validating the assumption that the system is well understood, reversible, and cannot move into a new dynamical regime. This assumption (smooth transitions in climate/nonlinear systems under forcing) is incorrect.

  16. I believe the classic geek speek for the a problem such as the climate problem is that it is EVIL!!

    Another very real but unfortunate aspect of the climate problem is that we have the population growth is roughly exponential issue, and the more people want more or better homes, food, health, entertainment, work. That is hooked in with the pop growth rate issue as well, in the sense that all other things being equal, more people means more demand for the basics or better (and, yeah, there’s a bunch of on-the-one-hand but then on-the-other-hand to and fro argy bargy if we want to quantify that statement, but let’s not and say we did).

    Once we go forward on the emissions growth curve for a bit – say, a decade – and then try retracing our steps – maybe by a combination of carbon sesequestration and curtailing of fossil fuel energy production – we will find that this involves aggravating more people than we started with. That bunch of extra people want what the rest of us have, and understandably so. This is in my opinion yet another good reason to go hard and fast at moving away from the increasing emissions scenarios currently being fed to us.

    So far only the Greens have stared the science in the face and made policy to match it.

  17. The problem at the moment is that the commitments from Annex 1 (developed) countries are so weak that it will be extremely difficult to reduce emissions enough after 2020 to give us a good chance of limiting temperature rises to degrees. Andrew Macintosh (from the ANU Centre for Climate Law and Policy) has shown that with likely outcomes until 2020, we would have to reduce emissions by around 5 percent per year later in order to have a good chance of keeping temperature rises below 2 degrees. This suggests to me that we will need to find a mechanism to tighten targets before 2020.

    I would prefer to have an emergency response now to needing to have a bigger emergency response in ten years time. I do agree with John that it is wrong to suggest that anything less would be a waste of time. To continue on a business as usual trajectory for any longer would make things even worse.

  18. I’m no greenthumb, so I don’t have detailed knowledge on how plants will handle more clusters of extreme hot days and nights, beyond my comments in an earlier post on this thread, and on what has been said about efforts to regreen the Monarto region near Murray Bridge. It is clear that it’s tough to attempt remediation of already marginal land, yet failure to do so may mean that there is no going back to farming on previously good land.

    With regards to Peter Wood:
    @Peter Wood
    I’ve had a skim through the article you linked to and I’ll have a closer look during the day. Thanks.

    With regards to Dominic:
    @Dominic Meagher
    I didn’t notice your post until I went to do this one. You’ve paralleled my basic concerns about fixation on the target temperature anomaly (eg 2 degrees) to the exclusion of the probability distribution characteristics for the various state variables in the climate system. A hotter climate (in Southern Australia, say) may mean that the variation in temperature is skewed towards the hotter end of the possible temperatures, which in turn makes clusters of extreme hot days/nights a much more likely occurrence. I don’t know for a fact that this will happen, but then this sort of uncertainty must be captured in our policy setting of targets.

  19. So the temperature has been increasing by .04C per decade due to Global Warming. So we’ve increased nearly 1C since the 60s.

    Australia’s wheat production in the 60’s averaged around 10,000 kt/annum, 14,000kt in the 80s and around 21,000kt throughout the 2000s. It appears that agriculture benefits from the increased temperature. We appear to be increasing wheat production at a rate equal to a doubling per 1C increase in world temp.

  20. Getting virtually any agreement would be a big positive right now. It’s not like the science(s) are rock solid, and neither can we reliably model the economy and technology in 50 years time. We can reasonably expect that the situation will be increasingly clearer as time progresses.

    Once there’s an agreement in place, it becomes possible to tune it – up, down or sideways – based on incoming data and analysis. We’re talking about the biggest environment management project ever here. It isn’t going away any time soon, so we can be sure that whatever is set up now will be changed periodically.

    And, anything that moves the discussion from the “I have the fix” approach to a slightly saner language of ongoing management would be a great relief, to me personally, at least.

  21. Prof.Quiggins has a right to be proud about his expertise,but, then he does it again by dropping in the word Delusional.There are many experts anti global warming whose expertise is thoroughly and normatively practical in orientation,rather than the bees knees of economics.When it comes to on farm stuff,even if he finds no academic record for my suggestions,they entered onto private and public lands via the bush telegraph and my handwritten letters to a local newspaper.Why be offside with people like The Climate Skeptics Party when the advantage of deeper thought like Donald Oats requires that deeper thought.Alright it is easy to say criticize the Dairy Industry for a whole lot of practices including water useage,but, history also points out that Milk has been used as products like paint.White paint,in fact, the same is said to be able to lower temperatures in the order of 2%.Carbon Dioxide can be turned into paint,white paint.Enough white paint,and you could cover a bloody mountain peak or three.And if the whole blaming on Humans thing was wrong,and just cycled out,well you would have three white bloody mountain peaks!? You can now continue your intellectual exercises,I have made my point!

  22. I suspect the stark conclusion from Copenhagen will be that these talk-fests only lead to more hand wringing, not results. In Australia’s case the ETS was emasculated then postponed a year. Any successor is likely to be as onerous to the big polluters as a fluffy duster. The 20% RET presumes we can increase non-hydro renewables five fold within a decade. If that were happening you should be able to look out the window and see at least one new wind farm on the horizon. Instead we delude ourselves with fables about outback geothermal and solar towers. The reality is that the conveyor belts fling as much coal onto the boilers as ever.

    Alas I suspect Australia will get serious about carbon mitigation after not one but several climate setbacks. By that time the horse may have bolted.

  23. Janama, grain yields are subject to variations in rainfall and seasonal conditions which in turn determines whether to plant or not and of course production levels which can vary from 10.0 – 26 million tonnes.

  24. I understand that Michael but our maximum production is increasing, NOT decreasing.

    People talk as if global warming is a future event yet it’s been with us since the 40s, possibly earlier – there’s no empirical evidence that an increase in warming is detrimental to our agriculture and I haven’t observed the wheat belt heading 400km north over the past 4 decades.

  25. Janama, whilst Australia’s wheat belt areas has increased fourfold since the 1940s, changing circumstances means Australia needs to keep abreast of the world by introducing new and innovative sustainable farming practices inline with the CPSR.

  26. Semi dwarf wheat varieties almost doubled production and made it worth while to fertilise adding further productivity. Australia also moved to more irrigated wheat, often as a second or rotation crop in rice and cotton enterprises.

    So, increased production by breeding, cultural practice and irrigation has so far kept ahead of global warming.

  27. It is worth stressing that people seem to be assuming linear and time reversible effects of warming. I’m not confident that assumption holds.

  28. Donald made some important points on population growth which also tie into JQ’s mention of short term threats to the Barrier Reef of over fishing and nutrient pollution.

    Sustainable Population Australia, SPA, is making a submission to Copenhagen on the role of population growth in GHG emissions. The ONLY submission on population growth.

    I realize population growth is an ‘out there’ subject to most people but, boiled down, it really is only the same old issue of sustainability vs unrestrained consumption, quality vs quantity, good stewardship or bad. It is high time we all grabbed a big handfull of ‘population growth’ consequences and rubbed it in the faces of our ‘growth’ captured polititians. I have been. They don’t reply. That tells me it is hitting a nerve because I have sent supporting emails on many other subjects and they usually reply to them.

  29. Protein matters have dropped in some cereal crops where experimentally carbon dioxide was present in a greater volume per measured cubic area.I don’t however think that will be a real problem,unless it becomes a defining moment in soil sequestration attempts.The growing of benign fungi in paddocks where cereal is grown,for many reasons including holding moisture or water seems to be worthy study that needs locational research.Some of this research has been taken over by the GMO friendly scientists ,and frankly some of these people have been wrong all their lives,but where there is money,there is a potential for lofty qualifications and farmer dependency.Friable soils with humus and gation qualities are not going to be the breeding grounds for failed cropping when the water profile is substantially low.Mobile Fog or Atmospheric sheeting moving like irrigation technologies,and probably compatible with existing irrigation technologies is only requiring some people to see if they can increase soil moisture profile from the atmosphere in this manner.Powering of the mobile Fog sheets needs some thought.Look up FogQuest,I think its called, where some successful pulling down of atmospheric moisture has worked..Wether this will still be useful in those locations in use,in the future needs some analysis.Back up with the Hilsch Vortex Tube technologies.As I have related before,there maybe a possibility of engineering into certain harvesters a capability of drawing atmospheric moisture down to ground well.

  30. I think there is a need to directly address the “why 350?” argument?

    Specifically, Hansen’s “Target Atmospheric CO2” paper.

    Without convincingly addressing all points in Hansen’s paper (including all feedbacks), I don’t see how a higher target can be justified.

  31. An article in the Age (2009-08-30) notes how the latest “drought” might be a more permanent change…

    Basically the SE Australia chunk including Vic and a bit of SA are exposed to lower rainfall patterns as the new normal. The scientist groups mentioned in the article used state of the art US numerical modesls to test what happens in SE Aus if there is no global warming trend, and then what happens when GHGs, aerosols and other human impacts are added. In the first case the conclusion was that SE Aus would have the usual climatic conditions with historical rainfall statistics. The second case shows an increase in the intensity of the subtropical ridge which pushes the rain bearing lows away from the southern part of Australia. I’ll caution here that the models provide statistical support for the hypothesis that the global warming trend from temperature data has an effect upon rainfall patterns – reducing rain – in SE Aus. However, the state of the art climate models are capturing numerous regional effects now; it means that climate models are lifting in capability and reliability.

    No doubt this will be written off in some parallel blog as government scientists conspiring to provide the government with another reason for an ETS, blah, blah, blah. Maybe, just maybe, there is something to the AGW theory afterall.

  32. My own view on the 35oppmv target is the same as my view on Code Red’s 300 target or some notional group’s proposal for 240ppmv.

    Who in his or her right mind wouldn’t want the lowest possible target?

    Dreaming up targets doesn’t get us there though and until someone can show how we can get enopugh people to do enough to stop us getting to 450ppmv the talk seems idle.

  33. lowest possible?

    0ppm wouldn’t be a good idea.

    Hansen has made a clear case for 350ppm in his “Target Atmospheric CO2” paper.

    Anyone who advocates a higher target needs to address all issues raised in the Hansen paper – especially feedbacks.

    Without convincingly addressing all points in Hansen’s paper, I don’t see how a higher target can be justified.

  34. I’d say that in practice 0 ppmv simply isn’t possible. The lowest possible given the cost constraints, the number of humans, the persistence of biota etc is probably about 240ppmv … and since there would be no marginal benefit going blow that the rest is moot.

  35. @Fran Barlow
    In practice 0ppm is definitely not desirable, as well as being totally impossible. At 0ppm, all plant life on Earth would be dead within months due to an inability to do photosynthesis from lack of CO2, followed by all animal life some months later. Fungi and some insects might survive a while longer but within a few years the planet would be ruled by the bacteria again.

    The thing to understand about targets is the inertia of the climate system. Although AGW is currently only about 0.8C (in the lower atmosphere where we live) to date, more warming is already locked into the system. The oceans haven’t warmed to the same degree and when they catch up then another 0.6C rise is expected AT CURRENT CO2 LEVELS. Aerosols (air pollution) in Asia are believed to be masking another 0.5C warming, so if the Asian economies clean up their air quality that would be added as well. So even if we magically stabilised CO2 levels at todays level we would still hit 2C. Other parts of the ecosystem will continue drawing some CO2 out of the atmosphere so this would remove a part of our future emissions but unless we can cut our emission levels rapidly, we are already at the point of seriously overshooting now. We will then need massive sequestration efforts to claw the levels back down again to avoid utterly catastrophic consequences for the world. And not just the Coal Industries wet dream of Carbon Capture & Storage. That is before we factor in other major ‘climate tipping points’ that could escalate the situation in decades to come. To those of you posting here, have you been paying any attention to reports of what is happening in the Arctic? Not melting Glaciers and problems for Polar Bears. Rather Methane release from melting permafrost and release from sub-sea Methane Clathrates. Early warning signs so far, nothing definite. But there seems to be a background noise in all the reports. The ticking of a timebomb.

    Humanity is caught in a very sharp cleft stick. Either we take radical steps to utterly cut CO2 emissions quickly, with real economic and social harm and, for some people in the world, misery and death as a consequence. Or we do less, not enough and too slowly, as is currently the likely outcome, and take the very real risk that Climate change, population growth and a looming world water crisis in agriculure combine to devastate our societies over this century. The consequences of the latter would be every bit as terible as a major Nuclear War, but one played out in slow motion over a 100 year period.

    Our grandchildren may come to pay an appalling price for the nearly 20 years wasted since the Rio climate summit of 1992.

  36. The problem with the stabilisation targets above 350ppm GHGs is that on the current evidence, we may well hit the target without any hint of stabilisation capability by that time.

    Those of us living in the driest state on the driest continent, especially those in the Murray Bridge/Mypolonga region, have just had August temperatures 0.9 degrees (Celcius) above the long term average for maximum day temp, and 2 degrees above the LTA for minimum night temperature. Rainfall was 34mm, which was below the LTA of 38mm. I suspect we’ve just had our hottest August on record. Until 2010, of course.

    All of which makes me feel like responding fairly pugnaciously whenever a local farmer says “when the drought breaks…”. If it is a drought we are in, then a lot of this year’s year 8 students have not known anything else but drought.

  37. @Glenn Tamblyn

    I wouldn’t take issue with anything you’ve propsed Glen …


    … and since there would be no marginal benefit going blow that [i.e. 240ppmv] the rest is moot

    @Peter Wood re: preindustrial CO2 concentration

    In the thousand years prior to 1850 it varied between about 240 and 280 ppmv. With hindsight, we know that 280 was the tipping point, so 240 is probably our margin for error.

    In practice, even if we were to reduce anthropogenic emissions to zero today it’s likely that the atmosphere would equilibrate with the ocean, with the ocean releasing some of its CO2 (and taking up less) slowing the decline in atmospheric concentrations. Of course, we’re not going to do anything of the sort.

  38. @Glenn Tamblyn
    the only thing I’d take issue with is the notion that moving strongly to do what is needed will of necessity cause widespread harm (social/economic). That is only the case if vast sums of money are wasted on stupid expenditure, as is the case now. Of course not wasting the world’s production requires an even greater change than responding sensibly to climate chagne.

  39. Nanks, I’m not sure what you are implying but the problems with ie the ozone within the Sydney Basin is due to bad urban design and outdated technologies. The quicker Australia moves to a cleaner and greener way of life the better.

  40. 1 degree or 2? I know that when things are desperate nothing will stop people putting agriculture ahead of natural ecosystems. We’ll be lucky to stop the rate of increase of emissions going up before we see 450ppm! Actual reductions? Not from Australia. Not any time soon. We are capable of better but not when leaders of government and industry still doubt climate change even exists or that there’s any urgency.
    The ETS may be a start but one that protects the industries it’s supposed to be penalising and that doesn’t impact fossil fuel exports at all? Our mainstream pollies and business leaders don’t get it yet or they’d know the best place for coal is in the ground – and be serious about policies that get that result.

  41. nanks

    My reasons for thinking that the scale and importantly the pace of the changes needed to keep the risks from the combined impacts of AGW, further population pressures and the looming hydrological crisis’s impact on food production is that they cannot be done in economically or socially neutral ways. The flow on benefits in latter decades more than make them worthwhile, but the short term pain will be real. The only way that real and mortal harm to some people in the world could be avoided is if every country in the world and every human being shared the burdens of this change equally.

    Consider the following:

    A recent study released early this year identified that to avoid dangerous warming, the world could only afford to release 500 Billion tonnes more CO2. This is equal to everything we have released since the start of the industrial revolution. However, at expected emission rates now we would reach this volume in just 40 years.

    Compare this with the following fron the International Energy Agency. Their Energy Technology Perspectives 2008 Executive Summary.

    On page 5 graph ES.2 is their projection for what can be achieved with new initiatives under their ‘Blue Map’ scenario, the more agressive of their options. It looks at energy changes using a variety of technologies that they feel may require Carbon Trading cost for CO2 of $200 – $500 USD per tonne. Current Carbon trading schemes are only talking of carbon prices of 10’s of $USD per tonne.

    Look at the area under the graph from 2010 to 2050 even with the measures they discuss. This is over 900 Billion tonnes and at the end of that time we are still emitting 14 Billion tonnes a year. This does not include non energy emissions of CO2 – agriculture, cement making, land clearance, etc. This does not factor in the possibility of various ‘Tipping points’ – Methane from the Arctic, forest dieback, the oceans reducing their absorbtion of CO2.

    The scale of change needed to ensure ‘adequate safety’ from what could be potential End of Civilisation consequences requires us to achieve changes 2 to 4 times greater than this. Such as..

    All fossil fuel power plants worldwide are shut down by 2020.
    Only carbon neutral vehicles are allowed on the roads by 2020
    We have totally replaced the use of Cement by 2020

    and many more changes within 10 – 20 years.

    Consider the capital losses from 10’s of thousands of power plants being shut down before the end of their working lives – Trillions of dollars.
    Consider how long it will take to build 1000’s of Integral Fast Reactors as suggested by TerjeP, can we do it in 10 years? Similarly the deployment of renewable technologies on this planetary scale in that time frame, let alone the massive problems of energy storage needed to complement Wind, Solar etc

    So our only alternative if we went down the path of radical emission reductions to stay within safe CO2 levels would mean things such as the equivalent of war time energy rationing, the end to economic development in the third world and economic catastrophy; The world going onto a war footing for a couple of decades. The chances of the worlds leaders taking us down this path are remote but if they did, do you really see the governments and people of the world acting in a rational and civilised way to share the burdens of this equally?

    Changes of this magnitude discussed by many people in this forum and in many other places are certainly achievable in a 30-40 year time frame and if managed properly would have few negative impacts. But to do it in 10 years would mean taking a wrecking ball to the world and people will get hurt.

    But to take until the middle of the century to make this change means IMHO theat the risks of catastrophy for our grandchildren are simply too high.

    Houston, we have a problem.

    Those years wasted since 1992 may prove very very costly

    So to all of you, when you consider ideas for action, filter them through the basic test of ‘What scale does this need to be done at, what pace, what cost?’

    Quantitave thinking needs to be at the very heart of our response to this problem because in many ways, the lack of quantitative thinking, our preference for looking at the world and our lives in predominantly qualitative ways is at the very heart of how we got into this mess. To anthropomorphise a little; Mother Nature is the Goddess of Numbers. She keeps count of everything, even when we don’t.

    As someone said on another blog ‘May our great great grandchildren forgive us!’

  42. @Ken
    Ken, unfortunately the policies required for us to stop contrubuting to climate change involve those very policies in situ across the world that support globalisation. It wont happen in my lifetime but it needs to happen that countries need to turn inward and no doubt Ill unlease the hounds of hell for saying it…but as Keynes said, the best you can do for the world economy is to look after your own economy and Ill take that as looking after it sustainably..

    As I said I have no hope the seeds of change (at a political and economic level and policy level) will happen in my lifetime…it requires a whole fundamental shift of mindset and perhaps that wont happen until the disaster of climate change is already upon us.

    I dont think, as Fran suggests, it should involve more quantitative reasoning….it becomes apparent to me that with the sophistication of quantitatove methods and pre prgrammed models, numbers can be turned this way and that and there are already too many being trained to accept others assumptions in models and statistical programs without question.

    It needs something more. It needs great normative views and judgements unhindered Im afraid.

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