Carbon-dense fuels are very cheap given the energy we extract from them, carbon-dense is practically a synonym for energy-dense. Additionally we can make them much cheaper yet through increasing efficiency -- just as an example UK plans to extract significantly more North Sea energy through in situ combustion and gasification of sub sea coal veins - definitely more efficient (and less costly) than digging big holes in the ground. Enhanced energy recovery from the oil reservoirs we so lightly tap to date may also be possible this way and holds much more promise for developing nations than harvesting low-density (320W/m^2) solar energy.

With regard to subsidies, according to the Energy Information Administration: $23.50 per MwH for wind, $24.50 for solar, $0.25 for oil and gas, whereas coal gets $0.44, nukes about $1.60, and dams $0.60, so I don't really agree about subsidies.

Finally, plants evolved under conditions of higher atmospheric carbon dioxide and commercial greenhouses spend real money generating the gas to elevate diurnal levels to about 1,000ppmv, so I can't claim to be too worried about food crops being exposed to higher levels than current ambient.

Glenn, I think if you are going to make a comparison between Victoria and Russia, you need to start with the fact that Moscow sits at 55 degrees north and Melbourne around 37 degrees South.  A common adage in Moscow runs along the lines of 'Our summers may not be hot, but at least it isn't snowing'.  The point is, we expect bushfires in Australia and our native vegetation has adapted and expects periodic fire episodes.  The situation is very different in Russia– birch forests don't enjoy being burnt.  And while it can reach 30 degrees during heatwaves in Moscow, recent temperatures have been extreme.  The real debate is whether this is anomalous weather, or a climatic trend.  Personally, having lived in Europe many years, I'm a bit concerned.  As a farmer in hotter, drier NSW, having just watched many Russian wheat crops destroyed... I'm a bit concerned.

Barry, do you really think $2 trillion dollars spent on global oil consumption is 'cheap'?  Do you think the externalities of the Mexican Gulf spill (and others) is cheap?  Coal is only 'cheap' because of massive economies of scale built up over two and a half centuries and some handy subsidies.  Digging a huge hole in the ground is actually really expensive.  No energy on earth is cheaper or more abundant than the sun.  However, currently harnessing it is not so cheap.  But apply the same economies of scale, or a fraction of the R&D that the coal or oil industries enjoy and you have a different ball game.  Throw in wind, wave, hot rocks, fusion and fission (if nuclear waste can be safely disposed), and why would we need carbon?

The 'CO2 is good for plants' is an often repeated throw away line that is simplistic, if not wrong.  It's up there with the 'they grew grapevines in Greenland and Vinland' line.  While some plants might grow faster, they often end up with less protein in their composition making them less nutritious to animals that depend on them.  The reality is that the effects of extra CO2 are varied and complex.

Gareth you could apply the same argument to wind, people have been harnessing it for transport and mechanical power for at least 5 centuries but despite the maturity of the technology have not managed to make the wind blow conveniently for human enterprise.

Efficiency is something we are still working on and quite successfully too, when you consider the declining carbon intensity of developed industrial societies. We still have a long way to go though since we only harvest a modest few percent of oil reservoirs and coal seams. How much more can we extract through in situ combustion and syngas production? Early work is quite promising. Gas resources are expanding enormously as we learn to extract from shale, etc., without even bothering with methane clathrate deposits, so "peak carbon" is probably still many centuries away.

Cheap, abundant energy supplies are certainly good for people and carbon dioxide is certainly good for photosynthesizing plants so the benefits are tangible but the hazards of CO2 emission remain uncertain, ranging from all losers in the worst case, through a mixture of winners and losers to a net benefit for people and planet. Either way the developing world will continue to use the cheapest and most abundant and reliable energy sources, carbon-dense fuels will be used in increasing quantity for the foreseeable future. Regardless of what the West does India and China will push global annual coal consumption up by 50% by 2020.

With regard to your disposable tagline about Russian fires even Der Spiegel put most of their problems down to failed top-down centralised control from the Kremlin. Paleo data shows Australia dries and suffers catastrophic fires during cooling periods due to reduced evaporation from the Indian, Southern and Pacific Oceans causing mega-droughts. Ice age Australia is dry and dusty but if you look at the Bureau of Meteorology time series here http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi?graph=rain&a... you'll see that Australia has been getting a little wetter through the 20th Century. Enhanced greenhouse effect from co2 emissions causing more or larger fires is not compelling.

Tony that's the 2nd time you claimed to have been waiting for a reply to your request for indemnity to my knowledge, I don't know who you confuse me with but as I told you last time I don't and couldn't offer indemnity. As I also replied then, carbon constraint is not a zero sum game. You look at it as wasting people's opportunity to develop using cheap and abundant carbon-dense fuel being zero cost but I most assuredly do not.

Moreover, if catastrophic climate change occurs (for any reason) then we will need the most abundant and affordable energy to protect the populace from extremes and we will need to have maximised wealth generation to develop and harden infrastructure against adverse events.

The indemnity you seek is more readily available from a "no regrets" policy but, and this is really the key contention between us, windmills and solar generation do not. Wind doesn't generate useful amounts of electricity during the low-wind situation of large, near-stationary weather systems so often prevalent during extreme events nor during the high-wind of intense pressure changes, also common at extreme events. Solar generates little during the succession of cold fronts and low pressure systems circumnavigating the Antarctic during the southern winter and so on.

Now, I don't expect you to indemnify me or anyone else against loss of electricity from wind farms or solar collectors during adverse events but I will certainly argue against any such reliance as misguided and wrong headed. Your absolutism and failure to examine consequences is actually quite frightening.

Can it be inferred the Moscow bushfires could be attributed to climate change and Global Warming?  So far over 770,000 hectares have been burnt and Moscow recorded a record temperature of 35.5oC.

Compare this to the Victorian bushfires, where 2 million hectares were burnt.  In the days leading up to the fire, temperatures in Melbourne reached 43.8oC and 44.7oC.  On the day of the fires the temperature reached 45.6oC.  Several towns were entirely destroyed 1300 homes were burnt and a total of 3,700 buildings were destroyed.  The Moscow fires, by comparison are not nearly as bad as the Victorian Fires.  The Royal Commission into the Victorian fires noted “it appeared the whole State was alight on Friday, 13 January 1939”. 

You read correctly, these stats relate to the 1939 Black Friday Fires, way before Climate change became a hot topic.  On the day of the 2009 Black Saturday fires Melbourne recorded it’s highest ever temperature since records have been kept, a whopping 46.4oC.  Less area of Victoria was burnt than in the 1939 Black Saturday Fires but more lives were lost (173 compared with 71).  The difference in life loss could possibly be attributed to population density (far less in 1939) and area burnt could have been affected by the fact that more forest and bushland had been converted to farmland.

Official temperature records began in 1859.  Prior to this in 1851 devastating fires hit Victoria on Black Thursday.  These fires burnt 5 million hectares (two and half times the Black Friday fires of 1939), and are to this day the largest known Victorian Bushfires.  Unofficial records show temperatures of around 47 C (117 F) were reported on the day of the Black Thursday fires of February 6, 1851. 

In February 1851 the industrial revolution was just beginning and the Victorian gold rush was just getting underway.  Climate change could not have been the culprit; in all probability the people of the day probably blamed the weather.

This is not to say that Climate Change is not occurring, nor to say that it is not caused by man-made carbon emissions.  It is simply to say that unusually extreme bushfires and heatwaves are nothing new, and their occurrence is not a scientific basis to conclude that global warming is real and caused by man-made emissions.  This use of bushfires to justify the case for climate change is hype, let’s stick to the science and ditch emotional hype.  This is needed to ensure that rational decisions can be made with regard to the planet, and our species, future and well being.

I think you'll find there are very few people 'desperately keen to do harm'.  This is a wayward assumption.  I don't think even BP derives pleasure from polluting the Gulf of Mexico.  But arguably they are inadvertently (or not) changing the climate and harming future generations.

The other assumption you make is that carbon constraint leads to harm.  I'm sure the fossil fuel industry is destined for some pain.  But leaving the global warming issue aside, unless we wean our economies off fossil fuels/non-renewable forms of energy we are ultimately going to face serious issues relating to rising fuel costs and explosive competition for dwindling fuel reserves.

Coal fired power stations were dreamt up by Faraday over a couple of centuries ago.  Surely it's time to move on to a cleaner, more efficient source of energy?  The mere idea that digging huge holes in the ground, extracting vast amounts of black rocks, shipping them great distances so that they can be burnt to heat water to drive turbines to generate electricity... should by now ring a bit absurd.

Energy is the one thing there is absolutely no lack of in the universe.  There are multiple options for generation, some more efficient than others, and some of which can provide base load power.  We already spend over $2 trillion on oil alone a year.  Imagine what a fraction of that could do if invested in sustainable/renewable energy.

And before you rush to promote the upside of climate change, I suggest you consult a few Russians... amongst others.

Barry, I'm still waiting for you to volunteer to indemnify the rest of us against the impacts of climate change if you're wrong.  This is only the 4th such request.  Come on - put your assets on the same line you want to put my children's future on.....

As I've pointed out before, if the IPCC is wrong, we get an embarrassed look, clean air, transformative technologies and a few ugly wind mills,  If you're wrong, what do we get?

A few points actually Steve:

1: The IPCC does not make any predictions whatsoever, they publish "storylines". Their range varies from observed to extreme.

2: IPCC storylines are not conservative at all and actually contain 250% positive feedback in case water vapour enhances greenhouse effect from carbon dioxide warming. Such amplification has not been observed in the open atmosphere but is built in as a safety factor in the same way medicinal dosages are kept far from lethality.

3: If you had actually read any of the sample workings I laid out in the linked comment you'd have noticed that I in fact used the IPCC's upper limit figures for estimated change, not wishing to minimise any potential effect.

With regard to "tipping points" I have considered them but don't give them particular weight. Not because they can't or won't happen but because the difference between what atmospheric carbon dioxide levels will be with a complete no-regrets policy by everyone and those that will occur if only the developing world continues using carbon-dense energy sources while the West enforces some sort of constraint is such a small window I don't find it worthy of consideration. Moreover, since the tropical belt does not cool radiatively now but must export its warmth through the temperate and frigid zones much of the developing world is not at risk of significant temperature increase. An expansion of tropical and temperate zones poleward will have upsides as well as down and does not keep me awake at night.

What I do find scary is people desperately keen to do harm, which carbon constraint will certainly do even if only by limiting trade opportunity for developing manufacturers, without performing due diligence and checking to see what their desired actions can realistically hope to achieve. Doctors have the Hippocratic Oath to "first do no harm", perhaps investors and would-be world savers should have one similar.

...is that a seemingly normal human being thinks that Joanne Nova, a "freelance science presenter, writer, professional speaker & former TV host" knows more about climate science than all the climate scientists!

As for Barry Hearne, have you ever though that if we throw in the towel on mitigation and reach certain tipping points and feedback loops that the problem may be amplified to such an extent that adaptation on a large scale is impossible? This is a real concern because as I understand it the IPCC figures are conservative predictions only.

But I do think Gareth that you missed the point. You ask what it would take to convince [apply favoured term here] that AGW is real and I suggest it doesn't matter whether it is or it isn't. I apply the IPCC's formulas and decided mitigation through carbon constraint is a really poor strategy which will do nothing to protect poor people or provide them any assistance whatsoever.

I laid out some sample workings of why I believe that to be the case this morning, here: http://www.climatespectator.com.au/commentary/carbon-emissions-electrict...

[Belated typo fix "the" => "them"]

I see myself as a sceptic.  I could never claim always to be right on any given topic, but I'm pretty good nailing the nub of an argument.  Given the overwhelming evidence from the most authoritative sources I can find, anthropogenic global warming is very real.  But that's just me, and in the scheme of things I'm not that important.

What worries me is this: at what point will climate change 'cynics' be persuaded that AGW is real?  How bad would weather events have to become– what would be that final bit of proof before they declared "OK, this is not good?"  Is there even such a point?  Sydney CBD flooded?  A bushfire through your living room, perhaps?  Jesus and Mohammed holding a joint press conference?  And how much of a drag on the conversion of fossil fuelled economies to sustainable/renewable economies (which is a good thing anyway) will all this denialism be?

At 60% of the way through 2010, isn't it a little early for proclamations or could this relate to an election cycle rather than a climate cycle?

People do notice weather extremes but are a little forgetful of climate extremes like the river Thames freezing over in winter, during the little ice age or grape growing in northern England during the Medieval Warming period. If you recall, that's the inconvenient period the CRU were trying to hide.

The climate alarmist brigade prefer to deny natural climate change, they do not apportion any percentage of the last 150 years of climate change to nature, or at least I've never heard of any apportionment. For the alarmists, natural climate change suddenly stopped in 1860. They refuse to acknowledge global temperatures fell between 1875 to 1915 and again between 1940 to 1975 and finally between 1998 to the present. These little inconsistent periods of the 'CO2 did it' theory are best ignored as they simply muddy the waters and get people thinking.

Better to concentrate on thousands of unsuspecting scientists, most of whom actually had nothing to do with the conclusions drawn in the IPCC report. Well the IPCC didn't want a survey of scientists, they just wanted a lot of contributor names for marketing purposes. Never let truth, science or integrity get in the way of a good headline.

Marvellous contribution by 'Barry Hearn', no wonder the Chinese are leading the world in building new coal fired power stations, they must study their history and learn lessons from it.

"Islamist charity" is surely a contradiction in terms.  I guess you meant Muslim charities which share brotherhood with the various forms of Islam.  However we may well have reason to fear the wrath of the righteous if we do not take responsibility for our emissions. 
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It is surely provocative to patronise thinkers in developing countries, when we ourselves are superstitious enough to claim virtue for a distant solar farm capable of a piddling 0.4 GW in sunny weather.  Try to brag about that to the flood victims in Pakistan!
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We have wounded the climate with our emissions, and now seek to trade rights to emit more.  These shrines in another country's desert won't buy forgiveness for our failings.
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Sentiments of worldwide revolution might well be worthy of our own youngsters if that is the pathway to rescue the climate for developed and undeveloped nations alike.

Interesting. Here's something else you can make a conditioned response to:

If global warming is indeed responsible for observed extreme weather events then there will be a more energetic atmosphere (that is what enhanced greenhouse is about, after all), so this will deliver an increase in the Accumulated Cyclone Energy index, right? You can't have a more energetic atmosphere without more energetic storms. Only problem is that it is currently quite low: http://www.coaps.fsu.edu/~maue/tropical/

Claiming simultaneous Northern Hemisphere drought and flood as evidence of the same malady is also somewhat schizophrenic. Is the Indian Summer Monsoon Rainfall enormously enhanced this year that Pakistan so suffers? Actually not, it is just a little below average but definitely inconveniently located for poor Pakistan. Has the Northern Circumpolar Jet Stream been altered by atmospheric carbon dioxide? There is no suggestion that is possible so carbon constraint is unlikely to affect current weather cell configuration, is it?

For Heaven's sake have a look at what is actually happening before howling "Denier!" and feigning distress. Making energy more expensive or less available will not help Pakistan, Russia or China. Nor will it relocate inconvenient and literally lethal weather systems drawn along by the restless ribbon of upper atmosphere winds.

Severe weather events happen and have always happened -- just not to so many people. Try a little more critical thinking and a little less conditioned response. More importantly, try actually applying the IPCC's formula to see how little bang you get for the mitigation buck and you might realise more people can be helped with an adaptation strategy. It may not have the same holier-than-thou glow but being effective is also a virtue.

There is no doubt we are an adaptable species. The key issue with release of carbon dioxide and other known greenhouse gases (that is, gases scientifically proven beyond all doubt as able to trap IR radiation) is whether it makes sense to release them in such enormous quantities that the composition of the atmosphere is measurably and significantly changed. Likewise filling the oceans with plastic bags or draining all the water out of a river system or removing virtually all the forest cover of a country - all extravagant or perhaps profligate things to do, particularly if the impact of doing so is not clear. Commonsense would suggest we ought to do otherwise, and work for concensus for all nations to agree on curbs on such behaviour. Such self discipline and concensus building is in essence why we are a successful creature and not still living in trees.

I get very frustrated by reading posts such as those by Barry Hearn.

Barry, look at what you are saying, how can heatwaves in Russia causing extensive bush and peat fires possibly ever be a cause for "societal growth and prosperity"? What about higher temperatures and possible drier weather here in Australia? Is that also going to trigger "societal growth and prosperity"? You should think about what you write before putting it here on the web for all to see.

To be honest I'm not surprised that cooling in the past may have caused instability, but that does not automatically mean that warming will not cause instability either. Logically, any major change in climate is going to have an impact.

The fact of the matter is we exist on this planet within a narrow band of climate variability that we and the ecosystem have adapted to. Any major changes are doubtless going to have significant impacts on our ability to survive within the biosphere.

To somehow glibly say 'cooling is bad, warming is good' (I believe I have correctly paraphrased you here), as you are saying, seems to me to be the height of climate change scepticism gone totally mad.

Maybe you can write something logical or constructive next time Barry?

I shouldn't be surprised any more, but it is remarkable how the climate change sceptics (let's leave it at that, in the name of politeness) are always the first ones to comment on stories like this... It's like there's an army of them out there, scouring the Internet for targets, and once one is found, the call goes out to launch an attack.

Nobody denies that there has been monumental climate change over the course of geological history, and of course, man had absolutely nothing to do with those shifts. This time around, however, there is another player in the game - us. Whatever is going on with the climate from a non-anthropogenic source, we are putting an additional layer onto the mix, with our greenhouse gas emissions. The overwhelming majority of the world's climate scientists tell us so. Unless you believe that they are all frauds, or on the take (I'm sure some poor, sad buggers do think these things), we have to pay attention to what they are saying.

If nothing else, we have to give the climate the benefit of the doubt and get moving away from these problematic emissions. The sky won't fall in if we "go green". We'll generate whole new industries and millions of jobs by doing so. There will be difficulties in the transition phase, of course, and we have to handle that as intelligently and sensitively as we can. But move we must.

I find it very hard to believe that these current climatic events are coincidental. I think they are a taste of things to come. I'm not panicking or trying to scare people, I'm just saying what I see and think.

One more thing - Paul could have mentioned the calving of that massive ice island off the Greenland ice sheet last week. Four times the size of Manhattan. It's all coincidental? Right.

While we are seeing severe natural disasters now happening, are they all really unprecedented in our known history of the earth or human beings?

That is perhaps one of the reasons many people may be doubtful about some highly exaggerated claims.

Can anyone honestly say that if the global temperature was one or two degrees lower than it is now, we would not have any natural disasters as severe as some of the current ones we are experiencing?

In the recent publication "Periodic climate cooling enhanced natural disasters and wars in China during AD 10–1900" which you can find here: http://rspb.royalsocietypublishing.org/content/early/2010/07/13/rspb.201..., Abstract: "Recent studies have linked climatic and social instabilities in ancient China; the underlying causal mechanisms have, however, often not been quantitatively assessed. Here, using historical records and palaeoclimatic reconstructions during AD 10–1900, we demonstrate that war frequency, price of rice, locust plague, drought frequency, flood frequency and temperature in China show two predominant periodic bands around 160 and 320 years where they interact significantly with each other. Temperature cooling shows direct positive association with the frequency of external aggression war to the Chinese dynasties mostly from the northern pastoral nomadic societies, and indirect positive association with the frequency of internal war within the Chinese dynasties through drought and locust plagues. The collapses of the agricultural dynasties of the Han, Tang, Song and Ming are more closely associated with low temperature. Our study suggests that food production during the last two millennia has been more unstable during cooler periods, resulting in more social conflicts owing to rebellions within the dynasties or/and southward aggressions from northern pastoral nomadic societies in ancient China." (Planet Ark Reuters piece here for those who don't Journal: http://planetark.org/wen/58787).

Throughout history warmer episodes are associated with societal growth and prosperity while cooler ones are associated with strife, privation and disease. Doesn't fit your thesis too well, does it?

Human societies have always been faced with changing conditions and probably always will. The correct response, as always, is to adapt to prevailing conditions, not attempt to lock the world in some kind of stasis becuase someone imagines this is how the Earth "should be".

Might I recommend some more reading? Try "Said Hanrahan" (John O'Brien, Around the Boree Log and Other Verses, 1921) http://www.middlemiss.org/lit/authors/obrienj/poetry/hanrahan.html -- it might just help you get over your tedious global warming hand-wringing.