Green Oversite


Climate Denial Debunk#
Skeptical Science
How to Talk to a Climate  Skeptic

Climate Change Denial

Bruce Barbour - 2009 (including July 2020 update)

Media Access for Climate Change Deniers

Climate change deniers are still getting a lot of media space, far outweighing the view more accepted by the scientific and wider community. I don't know why this is so. I have read some of their newspaper articles. Their arguments are usually not based on facts. Instead they cherry pick information from all over the place to support their claims (e.g. as last year was the only the tenth hottest year on record we are therefore not getting hotter - it we were it should have been the hottest - what a load of rubbish). If they find just one error or inconsistency in a claim by a climate advocate or between climate advocates, they make the huge jump and say all the claims by all climate advocates are wrong. Similarly with mathematical climate modelling - they use the spurious argument that if there is any inconsistency between the various models they all must be wrong. Similarly they claim that if the models can't predict the temperatures next month then how can they predict ten years out. They don't understand the difference between weather and climate. Most are not scientists, in which case I ask on what are they basing there scepticism? Self Interest? Are they getting paid (directly or indirectly) by the carbon polluters and supporters of the status quo? Just as the cigarette manufacturers would deny the harmful effects of cigarettes. Is it an "Inconvenient Truth" which if they acknowledged would require then to actual make difficult decisions and changes. Do they like to be contrarians, to stand out from the crowd, to make a name for themselves? I guess some would actually believe what they say and think it is all bunkum - though on what basis I can only speculate. The deniers are certainly not basing their claims on science or if they are claiming science back up it is usually from scientists that are not climate specialists, such as geologists.

Geologists in Denial

Some geologists are climate change deniers. Their reasoning is interesting (but wrong). They look at the geological history of the planet earth and see many instances of the planet cooling and warming and of much greater magnitude than currently experienced, long before humanity was on the scene. They therefore jump from this observation to say warming and cooling are natural phenomenon which can't be induced by man. It is the last part of this statement that is flawed. Because other natural processes have caused climate change in the past it can't be claimed that climate change can't be caused by man. No environmentalist / scientist would claim that natural climate change has not occurred in the past, the evidence is incontrovertible. However there is no logical reason to assume that natural (non-anthropogenic) climate change is the only possible cause for climate change.

The other day (May 2009) I heard a geologist (Prof. Pilmer I think it was) saying that it is a conceit by humans to think that they can effect a system as big as the Earth. Hasn't he heard of the ozone hole caused by humans releasing ozone depleting chemicals into the atmosphere - a problem that has now been addressed by outlawing these chemicals. Doesn't he believe that the current build up of carbon dioxide in the atmosphere has been caused by humans. Where does he think all the by-products of fossil fuel burning by humans goes?

Increasing Carbon Dioxide Concentrations

How can the deniers think that increasing the concentration of carbon dioxide (CO2) due to man made causes, from 280 parts per million (ppm) in pre-industrial times to 387 ppm now (that was in 2009 - it at 415 ppm in 2020) and to possibly 450 ppm in the future (Note 1) would not affect the climate on the planet. (The only way they could do this was if they were arguing that carbon dioxide allowed as much infrared radiation transmission as normal air and I have never heard them argue that.) While 450 ppm does not sound like much you have to consider the total thickness of the atmosphere. While the atmosphere of the earth goes up 100 km and more by that height it is very thin. If the atmosphere was at the density of the air at sea level all the way up its thickness would be 7.81 kilometres (Note 2). At this atmospheric thickness, if the CO2 was concentrated in one layer, at a CO2 concentration of 280 ppm the layer would be 2.2 metres thick. At 387 ppm the layer would be 3.0 metres thick (a 38% increase). At 450 ppm the layer would be 3.5 metres thick (a 44% increase) (Note 3). Its like putting an additional blanket around the earth, currently an additional 0.8 metres up to an additional 1.3 metres thickness or more if the concentration of CO2 increases past 450 ppm. Logically how can this not affect the Earth's climate to some extent when experiments show that carbon dioxide interferes with infrared radiation. And CO2 is only one of the green house gases in the atmosphere that are increasing due to the activity of mankind.

The other consequence of increasing atmospheric carbon dioxide concentrations is that this directly leads to increase acidification of the oceans. The consequences of this are wide spread, such as the destruction of coral reefs and collapse of various aquatic species. So even without the global warming aspect increased carbon dioxide concentrations need to be decreased to address the ocean acidification problem.

Also read my page addressing the significance of 400 ppm of carbon dioxide in the atmosphere. (Update: May 2019.)

Consequences of Being Wrong

I really hope that I (and all those scientists) am wrong and that they (the deniers) are right, that climate change is not occurring. I will gladly fall down on my knees in grovelling apology if the world is spared from climate change disaster. But unfortunately I doubt I will have to do this.

You also have to look at the relative impacts of being wrong. If I and all those scientists are wrong, and climate change does not occur, what have we lost if we have adopted an aggressive climate change mitigation policy? Possible the loss of a bit of economic growth. (though even this is not certain - a lot of new industries will start up). Additional energy costs and other infrastructure change costs - probably. Certainly a lot of change in the economy. A lot of the old polluting energy production systems will go and companies that are unwilling to embrace change will also fail. And there will be some not insignificant pain to individuals caught up in that change. (This will hopefully be short term and will need to be compensated for). People's lifestyles may have to change. However against this what will we gain? Cleaner air and a better environment. Better public transport and urban environment. Better health for urban dwellers. The Peak Oil problem will have been solved - it is going to have to be faced, with or without climate change - you might as well do it sooner than latter. Sustainable consumption patterns will have been established, putting the use of all of the Earth's resources - not just energy - onto a long term, sustainable basis. There will also be a whole raft of new industries springing up to supply green energy and services. Quite frankly I would be prepared to have the cost of these changes, regardless of climate change, if in towns and cities we could breathe beautiful fresh air, rather than the pollution we currently have to put up with. Surely that must be worth a huge amount to anyone.

If the deniers are wrong, we do nothing, or not enough, and climate change occurs what are the consequences? Massive sea level rises and displacement of populations living on islands and in low level coastal areas, more droughts leading to famine and refugee problems and possibly wars. More severe climatic events leading to a level of destruction of infrastructure and human life. Loss of many native habitats and extinction of many species. These are just some of the consequences.

It is clear to me that, even if not completely convinced by the arguments of the climate change scientists, the risks of doing nothing are so great that the precautionary principle should apply.

And if you don't believe me please read the linked sites in the left hand column. These sites do a much better job at debunking the arguments of the climate change skeptics than I could ever do.

July 2020 Update: What should we do about climate change deniers? It would be nice to be able to have a calm rational discussion with them and by doing so bring them around to seeing that climate change is caused by humans adding carbon dioxide and other greenhouse gases to the atmosphere, and that climate change is real and is an existential threat to humanity that should be tackled with urgency. However I doubt whether this is possible - certainly not by me and most probably not by anyone. On a few occasions I have had a discussion with a climate change denier in the YouTube comments section. Even if you think you have won on one issue they will not acknowledge this and will then go on to the next point in their dot list of talking points. It is like a never ending game of wack-a-mole - hit one argument down and another different argument comes up.

I sometimes still engage with climate change deniers in the YouTube comments section. The reason I do this is not in the hope that I will change the denier's mind - because I won't - but in the hope that if someone else that is perhaps undecided or uninformed was to read the response, see the error in the denier's logic or see the other side of the argument and so will not be persuaded down a similar path. If there is no contrary view put up then perhaps the uninformed or undecided may think that the denier is actually right - and adding another person to the deniers' ranks would be unfortunate.


1. From Wikipedia - Greenhouse Gases

2. From Wikipedia - Atmosphere of Earth

3. Avogrado's Law states that the gas volumes should be the same for a given number of molecules for ideal gases at same pressures and temperature. Wikipedia says that carbon dioxide can be treated as an ideal gas within reasonable tolerances. It shouldn't matter whether parts per million (ppm) refers to volume or number of molecules. The calc should be OK within reasonable tolerances. For interference with infrared heat radiation attempting to leave the earth's atmosphere it doesn't matter whether the molecules of CO2 are in one layer or spread out over 7.81 km, or 100 km, of the atmosphere, the probability of interacting with a molecule, and being re-radiated is roughly the same. (Updated December 2019.)

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