Climate Change Impacts

Climate change basics III – environmental impacts and tipping points

The world’s climate is inherently dynamic and changeable. Past aeons have borne witness to a planet choked by intense volcanic activity, dried out in vast circumglobal deserts, heated to a point where polar oceans were as warm as subtropical seas, and frozen in successive ice ages that entombed northern Eurasia and America under miles of ice. These changes to the Earth’s environment imposed great stresses upon ecosystems and often led to mass extinctions of species. Life always went on, but the world was inevitably a very different place.

We, a single species, are now the agent of global change. We are undertaking an unplanned and unprecedented experiment in planetary engineering, which has the potential to unleash physical and biological transformations on a scale never before witnessed by civilization. Our actions are causing a massive loss and fragmentation of habitats (e.g., deforestation of the tropical rain forests), over-exploitation of species (e.g., collapse of major fisheries), and severe environmental degradation (e.g., pollution and excessive draw-down of rivers, lakes and groundwater). These patently unsustainable human impacts are operating worldwide, and accelerating. They foreshadow a grim future. And then, on top of all of this, there is the looming spectre of climate change.

When climate change is discussed in the modern context, it is usually with reference to global warming, caused by anthropogenic pollution from the burning of fossil fuels. Since the furnaces of the industrial revolution were first ignited a few centuries ago, we have treated the atmosphere as an open sewer, dumping into it more than a trillion tonnes of heat-trapping carbon dioxide (CO2), as well as methane, nitrous oxide and ozone-destroying CFCs. The atmospheric concentration of CO2 is now nearly 40% higher than at any time over the past million years (and perhaps 40 million years – our data predating the ice core record is too sketchy to draw strong conclusions). Average global temperature rose 0.74°C in the hundred years since 1906, with almost two thirds of that warming having occurred in just the last 50 years.

What of the future? There is no doubt that climate predictions carry a fair burden of scientific ambiguity, especially regarding feedbacks in climatic and biological systems. Yet what is not widely appreciated among non-scientists is that more than half of the uncertainty, captured in the scenarios of the Intergovernmental Panel on Climate Change, is actually related to our inability to forecast the probable economic and technological development pathway global societies will take during the twenty-first century. As a forward-thinking and risk averse species, it is certainly within our power to anticipate the manifold impacts of anthropogenic climate change, and so make the key economic and technological choices required to substantially mitigate our carbon emissions. But will we act in time, and will it be with sufficient gusto? And can nature adapt?

The choice of on-going deferment of action is potentially dire. If we do not commit to deep emission cuts (up to 80% by 2050 is required for developed nations), our descendents will likely suffer from a globally averaged temperature rise of 4–7°C by 2100, an eventual (and perhaps rapid) collapse of the Greenland and the West Antarctic ice sheets (with an attendant 12–14 metres of sea level rise), more frequent and severe droughts, more intense flooding, a major loss of biodiversity, and the possibility of a permanent El Niño. This includes frequent failures of the tropical monsoon, which provides the water required to feed the billions of people in Asia.

Indeed, the European Union has judged that a warming of just 2°C above pre-industrial levels constitutes ‘dangerous anthropogenic interference with the climate system’, as codified in the 1992 United Nations Framework Convention on Climate Change. Worryingly, even if we can manage to stabilise greenhouse gas concentrations at 450 parts per million (it is currently 383 ppm CO2, and rising at 3 parts per million per year), we would still only have a roughly 50:50 chance of averting dangerous climate change. Beyond about 2°C of warming, the likelihood of crossing irreversible physical, biological and, ultimately, economic thresholds (such as rapid sea level rise associated with the disintegration of the polar ice sheets, a shutdown of major heat-distributing oceanic currents, a mass extinctions of species, and a collapse of the natural hazards insurance industry), becomes unacceptably high.

Unfortunately, there is no evidence to date that we are taking meaningful action to decarbonise the global economy. In fact, it is just the reverse, with a recent work showing that the carbon intensity of energy generation in developed nations such as the US and Australia has actually increased over the last decade. Over the last decade, the world’s rate of emissions growth has tripled, and total CO2 emissions now exceed 30 billion tonnes a year. China overtook the US in 2006 as the single biggest greenhouse polluter, and within a decade, it will be producing twice as much CO2. This remarkable rate of growth, if sustained, will means that over just the next 25 years, humans will spew into the atmosphere an additional volume of CO2 – greater than the total amount emitted during the 150 year industrial period of 1750 to 2000! Of particular concern is that long-lived greenhouse gases, like CO2, will continue to amplify global warming for centuries to come. For every four tonnes added during a year in which we prevaricate about reducing emissions, one tonne will still be trapping heat in 500 years. It is a bleak endowment to future generations.

Nature’s response to twentieth-century warming has been surprisingly pronounced. For instance, ecologists have documented numerous instances of shifts in the timing of biological events, such as flowering, emergence of insects, and bird migration occurring progressively earlier in the season. Similarly, many species, including insects, frogs, birds and mammals, have shifted their geographical range towards colder realms – towards higher latitudes, upwards in elevation, or both. Careful investigations have also revealed some new evolutionary adaptations to cope with changed climatic conditions, such as desiccation-tolerant fruit flies, and butterflies with longer wings that allow them to more readily disperse to new suitable habitats. On the other hand, some sensitive species have already been eliminated by recent climate change. For instance, the harlequin frog and golden toad were once found in abundance in the montane cloud forests of Costa Rica. But in the 1980s they were completely wiped out by a fungal disease, which flourished as the moist forests began to dry out: a drying caused by a rising cloud layer that was directly linked to global warming.

These changes are just the beginning. Under the current business-as-usual scenario of carbon emissions, the planet is predicted to experience five to nine times the rate of twentieth-century warming over the next hundred years. An obvious question is, will natural systems be able to continue to keep pace? There are a number of reasons to suspect that the majority will not.

Past global climate change characteristically unfolded over many millennia, whereas current anthropogenic global warming is now occurring at a greatly accelerated rate. If emissions are not checked, a level of planetary heating comparable to the difference between the present day and the height of the last ice age, or between now and the age of the dinosaurs (when Antarctica was ice free), is expected to unfold over a period of less than a century! When such catastrophically rapid changes in climate did occur, very occasionally, in the deep past – associated, for instance, with a large asteroid strike from space – a mass extinction event inevitably ensued. Most life just could not cope, and it took millions of years after this shock for biodiversity to recover. It has been estimated that 20 to 60 per cent of species might become extinct in the next few centuries, if global warming of more than a few degrees occurs. Many thousands (perhaps millions) will be from tropical areas, about which we know very little. A clear lesson from the past is that the faster and more severe the rate of global change, the more devastating the biological consequences.

Compounding the issue of the rate of recent climate change, is that plant and animal species trying to move to keep pace with the warming must now contend with landscapes dominated by farms, roads, towns and cities. Species will gradually lose suitable living space, as rising temperatures force them to retreat away from the relative safety of existing reserves, national parks and remnant habitat, in search of suitable climatic conditions. The new conditions may also facilitate invasions by non-indigenous or alien species, who will act to further stress resident species, as novel competitors or predators. Naturally mobile species, such as flying insects, plants with wind-dispersed seeds, or wide-ranging birds, may be able to continue to adjust their geographical ranges, and so flee to distant refugia. Many others will not.

A substantial mitigation of carbon emissions is urgently needed, to stave off the worst of this environmental damage. But irrespective of what we do now, we are committed to some adaptation. If all pollution was shut off immediately, the planet would still warm by at least a further 0.7°C.

For natural resource management, some innovative thinking will be required, to build long-term resilience into ecosystems and so stem the tide of species extinctions. Large-scale afforestation of previously cleared landscapes will serve to provide corridors, re-connecting isolated habitat patches. Reserves will need to be extended towards cooler climatic zones by the acquisition of new land, and perhaps abandoned and sold off along their opposite margins. Our national parks may need to be substantially reconfigured. We must also not shirk from taking a direct and active role in manipulating species distributions. For instance, we will need to establish suitable mixes of plant species which cannot themselves disperse, and translocate a variety of animal species. It may be that the new ecological communities we construct will be unlike anything that currently exists.

Such are the ‘unnatural’ choices we are likely to be forced to make, to offset the unintended impacts of our atmospheric engineering. Active and adaptive management of the Earth’s biological and physical systems will be the mantra in this brave new world. Truly, the century of consequences.

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By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

59 replies on “Climate change basics III – environmental impacts and tipping points”

Keep up the doom and gloom Barry – that way you’ll make sure there’s tax payer’s money for another First Class-all-the-way global jolly for you. It worked for Albert Gore.


This is such a great blog when it sticks to energy policy.

When it starts sounding like James Lovelock, I reach for my barf bag.

The human race lacks the ability to seriously harm the planet, no matter whether there are 8 billion of us or 800 billion. A hundred million years from now, the human race will be exactly like 99% of all species that ever existed—–EXTINCT.

No matter what we do, the planet will have the last word. How will we become extinct? Will it be an asteroid strike? Vulcanism? Disease? Your guess is as good as mine.


John McEvoy,you are a pathetic piece of work.If you don’t like what is written on this site then you are free to take yourself elsewhere and good riddance.


Barry,thanks for this post.Obviously you are talking right over the heads of deniers but that us easily done given the subterranean level they are on.

As for the rest of the population the vast majority are complacent beyond belief,and not only about climate change.Al that the aware can do,apart from their personal lives,is to keep hammering away at the consciousness,such as it is,of those who are not mired in ignorance.The decision makers need to be especially targeted.


Thanks Podargus. As the spin doctors say, repetition is key, and we can’t think that the problem is going away, or at least not getting worse, or that the fight for public attention is ever over (Note: this applies to energy policy too). It’s getting more serious, and more out of control, year in, year out, as nations continue to vacillate.


I guess in the runup to WWII, until the situation became crystal clear, people denounced Churchill for telling it like he saw it. Then they couldn’t put him into power fast enough.

The bozos who deny that it is possible for humans to affect the planet may be like the leaders of Dutch Jewish groups in The Netherlands, who, after the country was overrun by Germany, told their own people (Jews) that they should cooperate with the Nazis as they were rounded up to be sent to the camps, because the Germans were only interested in using them as war industry labour, and that families would be kept together. They got to get their children out. I suspect there is an element of this type of leadership going on with the people who post comments about reaching for their barf bags. By the way, I got that story direct from Franz Braal, a Dutch war hero who went to great effort to make sure he got it down to the last detail as he told it to me as an old man.

As you see, I don’t agree with those who say we should cater to deniers by serving up politeness to their jeers. I say call a spade a spade.

I was going to mention the Ramanathan paper and Schellnhuber’s reply but I see you link to a good discussion of those in your third to last paragraph.

One example of a “tipping point” I only recently read about is the paper “Dust as a Tipping Element”

Click to access 20564.full.pdf

which discusses how an area in Chad that “produces one half the aerosols emitted from the Sahara, which is the world’s largest source” can be profoundly affected by “minor adjustments to small features of the atmospheric circulation”, i.e. could change drastically as global climate changes. Apparently in the past the area has been as different as when it was the world’s largest lake 7,000 years ago, to now when it is the world’s largest dust source. The paper suggests it could revert to emitting zero dust in as little as one season.

Another study, “Increase in African dust flux at the onset of commercial agriculture in the Sahel region”

Click to access Mulitza_etal_N10.pdf

contains a 3,200 year record of dust deposited off NW Africa, which the authors also say is the “largest source of mineral dust in the world”, which they say indicates a dramatic rise in dust starting as cash crop agriculture started in the Sahel. The authors caution that this paper is a single record that proves only a limited area of Africa did this. However the increase is dramatic. This dust may be included in what the IPCC has taken to be the preindustrial, which makes it even more significant, as it is large and it is anthropogenic.


I guess under Prime Minister Abbott we won’t be sending any delegations to climate conferences. I find that less objectionable than talking big and doing nothing. Then if it all goes bad the knives will be out.


“the human race race lacks the ability to seriously harm the planet”
Unfortunately you have forgotten to point us to your unequivocal peer-reviewed research for this statement. Or is that just your own humble opinion – religiously founded I suspect.
Barry – another great post on the folly of continuing with our rush to pollute the planet. Keep on pressing the point – some of it may get through to the scientifically illiterate like GC and McEvoy. Your blog is all the better for having several approaches to informing the public and I for one enjoy the biological posts that you write.


We can cut CO2 emissions. But to do it quickly, we need to provide a cheaper source of energy. We can do that. But it does not involve renewable energy nor a price on carbon. As long as activists want to fight for this, there will be deays and resistance.

If instead, of arguing for expensive energy and for a pricve on catbon, we argue for low cost clean electricity, and show how it can be done, then a mass of people in the community will go for it and the polutions will be give a solution to their problem. Their problem is how to grow the economy so they can provide all the services the majority of the population demand amd at the same time clean up our energy supply.

It is possible, but not as long as idealists are morte interested in promoting their agendas for renewable energy, energy efficiecy and high cost electricity.

We’ve lost the opportunity for this election, but lets learn from this. Entrenced beliefs in a requiring the government to put a price on carbon is not helping. I for one am strongly opposed to it. Because I am convinced it is not the right way to proceed.


One of the members of the Nucleus 92 Exec Committee has been involved with CSIRO research into the distribution of insect habitats and ranges in eastern Australia. There’s no question about it. The place is getting warmer, and the ranges of various native moths and beetles are shifting south in response. This was a contributing factor in his joining our organisation.

I have no idea how the evil cabal of climate scientists managed to co-opt the bugs into supporting their spurious research. They clearly have some powerful insect whisperers in their midst. I suspect diabolical involvement.

That last paragraph was sarcasm.


Barry, nice article (as usual).

Of course one could go on forever enumerating environmental consequences, but damage to ocean ecosystems through acidification and warming may also be worth mentioning.

I was appalled recently to learn of a new study in Nature suggesting that phytoplankton in the worlds oceans have declined 40% since 1950 and are continuing to decline at 1% a year. As phytoplankton are the basis of the oceans food web and the biggest biological carbon sink, this would seem to be damned serious. It seems the decline is attributed to the warming of the surface layer of the ocean causing it to turn over more slowly thereby reducing the transport of nutrients to the surface.

It would be good to hear opinions about this.

The nature paper is here:

And a report from the Independent here:


According to Barry’s map, the tipping points are spread quite nicely and evenly around the globe. Surely they will balance up quite well in that case?


Hi Barry:

I too would like more on the phytoplankton decline, which concerns the operation of the “biological pump,” no?

also: what is the basis for the 80% figure for cutting ghgs? is the idea that cuts of this magnitude, plus the operation of the carbon sinks, will stop the increase in concentration at 450?

and why do I always see some variance in the concentration numbers? varying between 383 and 390?



Since the climate change is degrees and cms in scale it is definitely not wise to cripple the economy when we obviously need prosperity to combat the unforseen effects.


and why do I always see some variance in the concentration numbers? varying between 383 and 390?

The latest CO2 figures can always be found here:

There is a seasonal variation in atmospheric CO2. From memory, something to do with seasonal tropical plant growth.


A question that puzzles me is how to read recurring statistical outliers as opposed to statistically massaged trends. Right now it appears most of Tasmania above 300 metres is getting a heavy dump of snow. Yet July was the warmest since records began. Last year was the wettest since 1927. Yesterday a whale gave birth to a calf in the Derwent estuary for the first recorded time since 1820. I would need some convincing that something isn’t going on. What’s next?


@John Newlands

Not sure about the weather in Tasmania, but increased precipitation is some regions is predicted because of increasing specific humidity in the atmosphere due to increased temperature.

Tamino has a piece about increasing specific humidity here:

He presents a chart showing very high correlation between temperature and specific humidity – right down to yearly variations. In fact the specific humidity could be considered a “sanity check” of the temperature record. (As if we need another sanity check!)

While the specific humidity is rising, the relative humidity is expected to stay more or less constant. Intuitively we would therefore not expect an overall increase in cloudiness and a negative feedback through reflecting more of the sun’s energy back into space.


@John Newlands

On a more abstract level, Michael Tobis discusses outlier or extreme weather events here:

and observes:

“A great deal of what is wrong with the extra-scientific debate is the overvaluing of frequentist statistics in domains where physical experience and understanding applies.”

My take one what he is saying is that just applying some statistical measures in a naive fashion without proper reference to the underlying physical science (as deniers are prone to do) is not necessarily a good way of determining the “uniqueness” of some of the extreme weather events that we have recently seen.

It is the science that ties these events directly to global warming and not that such events are two standard deviations from the mean or such like.


Interesting links. Assuming the trend warming remains at 0.2C per decade it would be useful to have confidence bands for a range of measures like highest/lowest temperature, heaviest daily rainfall, longest dry spell and so on. These measures could assist planning for crop growth and harvesting, peak electricity demand, public health, river flows, storm damage and fire intensity.

To take one case; could Adelaide or Melbourne cope with several consecutive days over 45C? I’d expect power failures, rampant fires, emergency medical needs for the frail and severe water shortages. Right now Joe Public enjoys all the benefits of $6 a tonne brown coal so perhaps he should start thinking about the downside.



I recall reading recently (sorry I’ve lost the link) about an international conference oriented to some of things you suggest and to further work into possible forecasting of these events so that the victims may better prepare themselves. Maybe somebody else has a reference?


Great article Barry. Been in the Flinders Ranges for past two weeks. It’s hard to keep up with you and your other contributors but here goes:

McEvoy and Galloping camel: Don’t be put off by the insults of Podargus and others. There are many reputable scientists and others who don’t accept that man is the cause of the recent warming. I agree with them and, like you, have been accused of being a troll or worse on some of Barry’s previous blogs. They are quite convinced that AGW is happening and will never be persuaded otherwise. The people in general are having second thoughts about it and in Europe at least there seems to be a majority who are no longer concerned about it.

David Lewis: There’s no doubt that humans can affect the planet just look at what we’ve done to our Australian landscape. We’ve overcleared the land and over commited our waters to agriculture and irrigation with the result that the Murray is close to being stuffed and plenty of land suffering salinization etc. Your concern about the lake in Chad and its dust problem. It seems that extending agriculture over the past 3000? years [did I get that right ?]has led to desertification and a dry lake. We need to remember that lakes are temporal bodies and will probably all dry out eventually although over the very long term in many cases. From direct experience, I can tell you that Lake Eyre [ I walked around it over 33 days in 1982] was not always a dry salt lake. Along the east coast of the north lake I discovered copious quantities of stone tool flakes [quartzite, chert etc] which were clearly manufactured by the Aborigines during the time when they lived along its shores. It was full of fresh water then and in earlier times covered an area three times its present size [Lake Dieri]. At the end of the Pleistocene it gradually returned to its now familiar aridity. Lake Eyre scholar, the late Dr. John Dulhunty identified other distinct shorelines up to 20 km from the present lake shore. The change from fresh water lake to dry salt pan over the millenia had absolutely nothing to do with aboriginal occupance. Natural forces were at work to bring about that change. Most of you know that but it just confirms for me that nature is probably a bigger force than man in effecting climate change and global warming. Sorry “warmists”. I’m not yet convinced about AGW.

Ms Perps: Does absolutely everything have to be subject to “peer-reviewed research”? Mann, Santer, Jones etc weren’t very forthcoming on the attempts by others to look at their stats. Is it any wonder that many have doubts about their work?

Peter Lang: You are right Peter and you and I know and so do many others contributing to this blog that nuclear power needs to increase worldwide and as quickly as possible [20 years to get to say 35% nuclear] if we are going to reduce carbon dioxide emissions to an acceptable level within the short time we would appear to have. We need to stop burning coal for electricity if for no other reason than the toxic muck spewed out has killed and continues to kill tens of thousands around the world every year.

Tom Williams: Try to get hold of a copy of “Power to save the world-the truth about nuclear energy” by Gwyneth Cravens published by Alfred Knopf and sons New York 2007. I’ll lend you mine if you can’t get one. Contact me.

John Newlands: Yes John, What IS going on? Add to your list of statistical outliers the consistent rainfall falling across the centre and north of Australia at least four months after it should have ceased. November to April is the time of the NW monsoon. How come it’s still coming in winter? Very strange. Must be something to do with the different positions of the Equatorial [thermal] low pressure system and the Sub-tropical high pressure system. It’s great for the land up north and is helping to keep water pouring into Lake Eyre. Wouldn’t it be good if Lake Eyre was starting to return to a more humid climate as it was 15,000 years ago? We’ll never know.

Quokka: Could you please enlighten me on the meaning of “specific humidity” I taught all about relative humidity about 25 years ago but the term
specific humidity, I don’t remember. Please help.

Cheers everyone. Off to the Flinders again next week.


@Terry Krieg

There are many reputable scientists and others who don’t accept that man is the cause of the recent warming. I agree with them and, like you, have been accused of being a troll or worse on some of Barry’s previous blogs. They are quite convinced that AGW is happening and will never be persuaded otherwise. The people in general are having second thoughts about it and in Europe at least there seems to be a majority who are no longer concerned about it.

It’s not just a question of being “reputable” it’s also a question of expertise. And on the latter criteria, scientists with the expertise and actively publishing research on climate matters unquestionably form a consensus on the reality of AGW. Every national academy, scientific society and professional society of international standing that has issued a public position also subscribe to that consensus. In this context, the onus is on the deniers to unequivocally show the the science is wrong. They do not help their cause with nonsense about scientists just making it up for the gravy train of research funding or that humans couldn’t be the cause because they just couldn’t!

Claims that that public do not perceive global warming to be a problem are just not born out by the facts. This 2010 World Bank survey of public opinion shows that in every country surveyed, a majority perceived global warming to be a problem. Strikingly, in many countries of the developing world opinion is quite overwhelming. Perhaps they have a better feeling for the hell that may lie ahead for their children.

It would be interesting to see what the Russian public think about AGW at the moment.

Mann, Santer, Jones etc weren’t very forthcoming on the attempts by others to look at their stats.

I suggest that you read what Ben Santer himself has to say about some of the climategate nonsense and in particular his correspondence with a serial pest by the name of McIntyre.

Close Encounters of the Absurd Kind

Could you please enlighten me on the meaning of “specific humidity” I taught all about relative humidity about 25 years ago but the term
specific humidity, I don’t remember.


@Terry Krieg.

Thank you very much for the offer, however I have already read it. It was highly factual and interesting, however I found her writing style highly distracting (as if it were a novel). I was going to try and get Tom Blees ‘Prescription for the Planet’ but my local book store says its out of print.


Tom Williams, on 20 August 2010 at 10.00 — hanks for the link.

Terry Krieg, on 20 August 2010 at 18.11 — Specific humidity is also called absolute humidity; the amount of waer vapor in the air. Relative humidity is the percentage of water vapor compared to the maximum (at the air temperature; it varies).


@ Benson.

No problem.

From Thermodynamics, I seem to remember that ‘Specific Humidity’ is the ratio of the mass of water to dry air, in any given volume. A specific humidity of 33% would give 1 part water to 3 parts dry air.

Relative Humidity: at any given temperate, air has a capability to hold moisture. As temperature increases, this tends to rise. The amount of water vapour in the air, compared to what is possible at that temperate, is the relative humidity. This can go up to ‘saturation’ where RH is 100%.

Hope that helps.


Quokka, thanks for the link to Santer’s rebuttal. Seems a very reasonable piece to me. How come “discernible effect” has been interpreted as “catastrophic” by the climate “alarmists”? Or did I miss something in Santer’s rebuttal?


I’m not sure what Mother Nature has to do for climate non-alarmists to raise an eyebrow. It seems 20% of Pakistan underwater, 173 Victorians incinerated or Russian peat swamps spontaneously combusting don’t cut it. I’d like to know just what it would take.


Quokka, thanks for the link to Santer’s rebuttal. Seems a very reasonable piece to me. How come “discernible effect” has been interpreted as “catastrophic” by the climate “alarmists”? Or did I miss something in Santer’s rebuttal?

The word “discernible” is used in 1995 IPCC report in the context of whether there is a discernible human influence in observed climate change. In other words whether it can be, at least partially, attributed to human activity.

Whether such change may or may not be catastrophic was not the subject of Santer’s article.

It is rather illuminating to see that after McIntyre’s harassment of Santer for data that was already freely and publicly available, he did precisely nothing with it. And this is universally true of anything and everything obtained by FOI requests in the whole sorry climategate saga. It was a nasty piece of politics principally designed for character assassination of leading scientists.

Santer sums it up very well:

“My research is subject to rigorous scrutiny. Mr. McIntyre’s blogging is not. He can issue FOIA requests at will. He is the master of his domain – the supreme, unchallenged ruler of the “ClimateAudit” universe. He is not a climate scientist, but he has the power to single-handedly destroy the reputations of exceptional men and women who have devoted their entire careers to the pursuit of climate science. Mr. McIntyre’s unchecked, extraordinary power is the real story of “Climategate”. I hope that someone has the courage to tell this story.”


Thanks Tom Williams. I did know what RH meant. You could have added that any further cooling after saturation [100% RH] will cause some condensation and thereafter, that cloud will form and also that precipitation might follow.
John Newlands, the unusual [for us] events which caused the Pakistan floods, the Victorian bushfires and Russian spontaneous combustion of the peat bogs aren’t necessarily caused by AGW are they?


Terry Krieg

Thankyou for your interesting first-hand observations concerning Lake Eyre. I read that the Dead Sea is evaporating quite rapidly right now, with the shore-line receding some distance each year. One only needs to look at the many salt-flats around the globe, and to consider the many deep and thick layers of pure salt encountered by oil exploration drilling to realise that this process has been going on for millenia. To clear up a few mis-conceptions of other bloggers, I do not deny that the climate is changing, and neither do I rule out that there is some effect upon it by mankind. The flora and fauna of the planet have always been in some kind of symbiosis with the physical systems of the atmosphere. What, for example, is the origin of limestones? I recall from my geology classes that the atmosphere was once principally CO2 with an abundance of anerobic bacteria present. The fixing of CO2 into limestones gradually led to an increase in oxygen concentration up the present levels and subsequently new life forms. I don’t hear anyone here lamenting the ‘catastrophic’ destruction of the earlier CO2 atmosphere and it’s fauna. I take a philosphical view of the evolution of the earth – if the climate is changed by the actions of one species it supports, so be it. That is how it has always been. I do however support sensible and pragmatic husbandry of the earth and it’s resources and the protection and promotion of natural systems and their beauty. I also support the sensible attitude of Barry Brook to nuclear power. What I do not support is the hi-jacking of economic policy on the basis of spurious panic. I wonder how many warmists here actually support their own case by voluntarily paying additional State taxes and eschewing, for example, air conditioning and automobiles? And how many trees did you plant last year? I would be interested to hear. For my own part, I live off grid, well away from any conurbation and provide my own fuel from coppice planted 25 years ago, my own power, water, waste disposal and most of my own food.

Have a look at this conservation technology for example:

Each dam costs about $20,000. So for the wasted cost of the publcily-funded Copenhagen jolly, 1,000 could have been built. Or millions of trees planted. This is what we should be actively doing instead of ‘carbon trading’ or shouting at others anonymously on computer screens.


OK thanks Quokka,
I accept that Santer did not say that AGW is “catastrophic” but lots of other people have. What do you think? I accept that we may have contributed to the warming climate but find it difficult to accept that we are responsible for all/most of the recent warming. And thanks John McEvoy for your inspired personal effort in living sustainably. And I agree that economic policy is being hi-jacked on the basis of “spurious panic.” Even if the “warmists turn out to be right, they should try to become a bit less shrill about their perceived planetary doom. They need to get on with working towards replacing coal and fossil fuel burning for electricity with the only other base load option viz nuclear as Barry has been suggesting on his blogs.


John McEvoy an alternative approach to sand dams is shallow bores in sand aquifers
If shallow enough the pumping can be manual. Unless the water table is 50cm or so below the soil (eg the Nile delta in Egypt) I don’t think human power is effective for watering large scale crops. I agree we must assist the Third World with clean water but also family planning.

As to primordial CO2 I would say that was then this is now. Humans now require a fairly narrow comfort zone of temperature and calories and psychic needs such as entertainment and mobility. We’re not resilient microbes. My understanding is that lime and CO2 from the volcanic conditions of early Earth formed limestones with the aid of tiny critters like forams whose carbonate shells fell to the sea floor. Shells of such tiny critters alive now are weakening as the oceans become more acidic. This could be largely because one macro-species H. sapiens is converting underground carbon back to CO2 at the rate of several tonnes each per year, not micrograms each. The little critters have been swamped.


Another great article. And some interesting discussion to follow. Bit of deja vu though, Barry: “during the 150 year industrial period of 1750 to 2000!” should be 250 year period ;)

The second last paragraph could be viewed as a little controversial, I’d say. Something I’d definately like to explore more. Conservation planning is becoming more and more important in this rapidly changing world, and our fellow species are going to need all the help we can give them to overcome the synergistic effects of habitat loss and fragmentation, invasive species, over-exploitation, extinction cascades, and now climate change.


Terry Krieg,
Many thanks for your kind words. This is such a fine blog that I plan to hang out here even though I have strong disagreements with many of the participants and occasionally with the Maestro himself.

While I agree with the people who say that mankind is affecting the planet, what we are doing is much less than what other life forms have done. Furthermore, change is not necessarily a bad thing. It depends on one’s perspective. I am an oxygen breathing life form comfortable in a warm climate (Florida). Anaerobic life forms and polar bears may see things differently.

Mankind’s contribution of ~100 ppm of CO2 to the atmosphere is warming the planet but the effect is more beneficial than “Catastrophic”. In my opinion a warming trend is much less to be feared than a cooling trend.

Earth’s atmosphere is over 20% oxygen thanks to “primitive” life forms. Mankind’s achievement (0.01% increase in CO2) pales into insignificance by comparison. The life forms that created the oxygen also removed the dissolved iron from the oceans leading to the creation of iron ore deposits. Events at that level are worthy to be called tipping points as they paved the way for explosions in the number of living species!


‘Mankind’s contribution of ~100 ppm of CO2 to the atmosphere is warming the planet but the effect is more beneficial than “Catastrophic”. In my opinion a warming trend is much less to be feared than a cooling trend.’

I wouldn’t be so sure that an increase in temperature will be entirely beneficial. I would recommend the Lynas book that was mentioned earlier. A few decrees of temperature has destroyed entire civilizations in the past.

I hope I’m wrong though.


Terry Krieg, on 21 August 2010 at 13.38 — Claimte distrupton, otherwise known as AGW, certainly contributes to the likelyhood of those (and othr) extreme events.

By the way, don’t pay any attention to gallopingcamel, who clearly needs to aim for the nearest outhouse in his gallop. Do read what Mark Lynas has to say about (some of) the effects of a warming climate.


Many people say that the Lynas book is highly alarmist, and looks at the worst case scenario. I honestly thought that it was quite fair, and looked at *all* the effects of AGW, including the good bits. He mentions bad things such as aridity, sea level rise, damage to ecosystems, in the sea etc but he also mentions how in some parts of the world there will be longer seasons, better growing conditions.


When considering future effects, it’s really important to understand that increase in temperature and changes in precipitation will vary considerably by region. It won’t be just a case of everywhere being a few degrees warmer.

For example models project simply massive warming at high latitudes. This is already being clearly observed.

It’s hard to see the warming of the Amazon of 8-10C this century under a high end scenario shown in this presentation as anything other than catastrophic.

The presentation is from 4 Degrees and Beyond Conference


I really don’t understand why some people claim that they “accept climate change is real” but that “it is mostly beneficial”. These people seem to have almost no understanding of biological systems and ecology.

We are already driving the most rapid and large scale extinction event since the Cambrian explosion (we have little understanding of the Precambrian world).

The climate is warming at a rate 30 times faster than at the end of the Pleistocene glaciation.

There is no evidence to suggest that already highly stressed and fragmented ecosystems will respond well to this rapid change (the palaeontological records suggest just the opposite).

We rely on functional ecosytems to survive and function as a civilisation. E.g. a 1997 paper by Costanza et al. (, put the (non-market) value of 17 ecosystem services for 16 biomes at $33 trillion dollars – a conservative figure which was almost double that of the $18 trillion global GNP at the time.

Why shouldn’t we be alarmed by this?


Tom Keen.
As you say, climate change is real. However, determining what is beneficial depends on one’s perspective. I like a warm climate while Aleuts (presumably) prefer colder conditions.

You seem to think that humanity is capable of changing climate significantly so how much warming or cooling do you recommend?


Adopting utilitarian philosophy, i.e. the greatest benefit for the greatest number of people (and species), I take the perspective that we should stop driving the temperature up. A great change in global climatic conditions over a very short period of time will almost certainly have more negative effects on the world’s population than positive effects, by far. Your underhandedly stating that, in this instance, “determining what is beneficial depends on one’s perspective” is pure sophistry.

James Hansen recommends we aim to bring atmospheric CO2 concentrations back down to 350 ppmv. Aiming at that certainly won’t cost us the world.


After reading all the posts (up unti lAug 23) I have to say that I am amused and entertained by the many well meaning alarmists but certainly dont find anything of a convincing nature which should lead to panic. I, like many others, have now read books and various publications from well known scientists as well as climatalogists who dispute most of the AGW claims. At the very least sufficient to say claims that the “science is settled” do cast serious doubts on what otherwise could be a sensible debate.
I do suggest that some of you should perhaps take two asprins, sit down quietly and resist making yourselvs ill and read something from noted and renowned authorities who just smile with raised eyebrows when confronted with this “bad science” I don’t mean to be offensive to the well meaning AGW ists here, but do just take a moment to read publications from others whose names appear on the list of scientists you will find here :


@Robert Stewart,

Sorry you will have to do better than a hundred signatures. The American Geophysical Union alone has over 50,000 members and it is but one of the many science bodies of international standing that assert the reality of AGU. None dispute it.

Instead of this silly game of dredging up a few skeptics, some of whom hold academic positions, you would be better advised to look at the evidence. You could start here where you will find just about all the skeptic arguments dealt by reference to the scientific literature


Thank you for your advice quokka but I have read enough of what is written on that site to still leave me unimpressed. I dont call it “a silly game” to be influenced by any number, that clearly seems to be what has influenced you. Children play “silly games” and thats healthy for them but as mature educated adults we should not be swayed by numbers but by all reasonable research at our disposal. Lets not forget, history is full of even nations who have followed the taught mantra of political parties or other self interest groups to the eventual detriment of millions. Certainly far from a silly game, I still emplore all who visit here to look at other possibilities before condemning us to hysteria over something which if is true, could not be halted by the crippling measures promoted by alarmists.

I do not doubt that climate change is occuring, indeed the evidence to that is not disputed. I do have doubts it is because of human activities at least to such an extent that is being preached by “the many”. Mans pollution of our environment can and does have dreadful effects , we and future generations are the losers and will undoubtably pay the price. That is something we all can influence here and now but not if our present ndustries are crippled with huge taxes which would surelly stifle solid growth and achievement. such as would be imposed by alarmists. If indeed AGW is destined to occur, surelly it’s only with strong R & D with the assistance of healthy industry which will put us in a position that we can overcome. No, I am not arrogant enough to believe that we can influence the environment to such an extent or have any effect which could be compared with those of Sun The Sea and the effects which they do have on our planet. And ” No” I don’t think the emporers clothes are grand either,


That is something we all can influence here and now but not if our present ndustries are crippled with huge taxes which would surelly stifle solid growth and achievement. such as would be imposed by alarmists.

Just what has the atmospheric effect of CO2 and other GHGs got to do with taxes? You are very confused.


A couple of posts over at SkepticalScience discuss predictions made by climate models published in 1981 and 1988 by James Hansen. As one of the authors put it “Hansen hit a home run” as the temperature record now shows warming well outside two standard deviations of natural variability from the mean with Hansen’s predictions being quite close to the actual warming.

The next time deniers start waffling on about science and falsifiable predictions, there it is – and with > 95% confidence just for good measure.


“Just what has the atmospheric effect of CO2 and other GHGs got to do with taxes?”

It’s a fairly common trend among AGW skeptics to conflate the science with a fear of what they perceive to be the response to the findings of the science.

“present ndustries are crippled with huge taxes which would surelly stifle solid growth and achievement.”

And you’re calling us alarmists? I think you might need to sit down for a while.


What a bunch of morons! i’ts obvious not many hear dare to look at whats really going on Internationally in uncovering this fraud. I wont waste my time hear anylonger, I know it might be a little over your head. When this has all passed, and it will, try to do something more constructive with your time.


Robert Stewart
I would say your denialist position on CC/AGW is not shared by many – that is if the low numbers of supporters your party,The Climate Sceptics, polled in Saturday’s election is any indication.


Great post. One I can suggest plenty of people read. New and uptodate
summaries are important to counter the general apathy that has
descended (on Australia at least). I’ve been off-line attending to other issues
and am always amazed at how Barry keeps BNC always rolling along!


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