Top 10 AGW Denial Myths

I’ve long viewed the anthropogenic global warming (AGW) denial movement with a certain sense of bemusement. The causal links are rock-solid – could it really be a coincidence that atmospheric CO2 levels started rising at the very same moment as industrial civilization got into swing, within decades reaching magnitudes big enough to decisively interrupt the glacial-interglacial cycle that previously held steady for hundreds of thousands of years? Is it really surprising that given the heat-absorbing properties of CO2 (known to science since the 18th century), global temperatures entered into a period of steep ascent since the 1970s, rising by around 0.9C from the 1900-1910 period to the last decade? Occam’s Razor anyone? And considering that only 6C or so separate us from the Ice Ages, when ice sheets descended into central Europe, southern England was a polar wasteland scoured by icy, dust-laden winds and dessication affected even the tropics, should not even the possibility of seeing the world warm by up to 6.4C during this century – corresponding to the high end of the IPCC’s forecasts in 2007 – invoke a certain level of concern?

I plan to write more on climate change, since it is going to be one of the key trends of this century (along with resource depletion and growth in computing power). But for now – and to forestall any future objections – I would like to take a moment to expose the top myths and misconceptions of AGW deniers.

10

It’s all a conspiracy – scientists want research funding and environmentalists want to impose socialism on us.

Frankly the idea that tens of thousands are colluding in a massive conspiracy is risible. If anything it is the denier camp which has economic incentives to promote their views, given the funding they receive from the fossil-fuel industry. The Bush administration scientists pursued a campaign of disinformation and outright censorship regarding AGW. So who are the real conspirators?

9

In past warmings temperatures in Antarctica began rising some 800 years prior to rising CO2.

The warmings took 5000 years to complete, so CO2 can’t account for just 1/6 of it. The initial warming is likely related to the Earth’s orbital cycles around the Sun. After a certain critical level of temperature rise is passed, more CO2 is released into the atmosphere – perhaps from its deep ocean sinks, since it takes around a millennium to diffuse heat to the ocean depths. This further amplifies warming in a positive feedback loop. Read more here and here.

8

There is no scientific consensus on AGW. And even if there is, it doesn’t mean it’s right.

Yes there is. In a January 2009 poll, 97% of climatologists active in research today said they believed that “human activity is a significant contributing factor in changing mean global temperatures”. A 2004 study by Naomi Oreskes of close to a thousand papers related to global climate change found that not one rejected the Scientific Consensus on Climate Change.

Though consensuses are sometimes wrong, they are right in the vast majority of cases. Though Patrick Michaels may claim there is a “paradigm problem” (borrowing from T. Kuhn’s Structure of Scientific Revolutions) with the conservative IPCC which serves to suppress mavericks, it goes the other way too – the IPCC generally neglects to mention new, outlying research which suggests that climate may change at a much more sudden and violent pace because of previously-unknown positive feedbacks and underestimated climate sensitivity.

7

Satellite sensors and equipment on weather balloons show evidence of cooling, thus disproving that eight of the hottest years have been since 1998 and other sensationalist claims.

Satellites don’t just measure the troposphere (the lowest level of the atmosphere) – which is what matters – in isolation, but also the higher stratosphere. The latter is expected to cool during global warming, because more heat is absorbed by the Earth and less is re-radiated into space. Furthermore, satellites are dependent on weekly recalibration by weather balloons so they cannot even be said to be independent.

As for the weather balloons, the problem is that during the 1960’s and 1970’s their on-board thermometers were not shielded from the Sun’s glare – thus inflating temperatures for that time period. Since this (obvious) oversight was fixed in the past couple of decades, the juxtaposed records appear to invalidate global warming…appear being the operative word. For when the analysis is restricted to just night-time measurements, surely enough the data shows a clear warming trend.

6

With “friends” like Al Gore, the global warming lobby needs no enemies!

Al Gore is a popularizer who happens to make good money from his activities. He has an admirable spirit of capitalist enterprise. Good for him. For the record, I haven’t even watched An Inconvenient Truth in full (and don’t plan to any time soon – it is nothing more than a basic and long-winded intro to the subject). The pilot fishes who drone on about AGW-supporters being “Gore’s dupes” are (US-centric) idiots.

And though Jurassic Park was brilliant and Prey was very good, with “friends” like Michael Crichton the AWG denial lobby needs no enemies!

5

Surface measurements indicating warming are flawed because increasing urbanization over the past few decades skewed the global data upwards, since cities hang on to heat better than the natural landscape.

Intuitively unlikely, because the greatest warming took place over Arctic regions well away from big population centers (global warming is more severe there because retreating ice and reduces snowfall diminishes the albedo of the land, resulting in greater heat absorption). Furthermore, urban heat islands occur mainly at night and are reduced in windy conditions. A study showed that global temperatures have risen as much on windy nights as on calm nights, “indicating that the observed overall warming is not a consequence of urban development”.

4

The global warming alarmists base their theories of man-made climate change on spurious allegations of a “Hockey Stick”, and neglect the dominant role of water vapor as a greenhouse gas.

Late 20th century temperatures are indeed anomalously high relative to the past millennium, thus forming a hockey stick on a temperature over time graph for the period. Evidence for AGW is far more extensive that just this, however.

Although water vapor is indeed acknowledged to be the most important greenhouse gas, it is primarily a feedback because of its extremely short (ie measured in days) residence time in the atmosphere. This means it merely responds to forcings such as CO2 levels or solar radiation. Increased anthropogenic emissions of greenhouse gases will amplify the greenhouse effect, strengthen evaporation and increase the amount of water vapor in the atmosphere.

3

You can’t use computer models to predict something as complex and chaotic as the global climate.

Though the details are indeed hard to capture, it is easy to see that a thicker blanket of greenhouse gases will cause the Earth to absorb more heat and force the climate system into a new, hotter and more energetic equilibrium. It’s also clear that due to changes in albedo, some areas will warm faster than others and global water and air flows will be altered. There is nothing wrong with using computers to model them by solving lots of physical equations – it’s much quicker than doing it by hand (speaking of which, in the 1890’s the Norwegian chemist Svante Arrhenius solved the riddle of the Ice Ages, attributing it to and correctly predicting the lower CO2 levels of that time; using the same method, he forecast a temperature rise of 5-6C for a doubling of CO2 levels, thus almost mirroring the IPCC’s high-end scenarios). Finally, it’s not all computer models, of course – there’s also paleoclimatic studies, which if anything hint at an even more pessimistic state of affairs. Our current atmospheric CO2 level of 384+ ppm was last observed during the Pliocene 3mn years ago, when global temperatures soared by 3C.

2

Climate fluctuations are all down to solar cycles and cosmic rays.

This does not account for the strong warming seen since the 1970’s – as you can see in the graph below, direct measurements of solar output since 1978 show a steady rise and fall over the 11-year sunspot cycle, with no upwards or downward trend.

Though there are arguments about the relative importance of solar forcing in the distant past, it is clear that in the present day its effects have been largely swamped by the sheer amount of CO2 we’ve emitted – though it continues playing an important role as perhaps illustrated by how the 1998-2003 period of mid-latitudinal drought coincided with the peak of the most recent wave.

Similarly, cosmic rays can’t explain the recent warming either.

1

Global warming my ass! There’s a mighty blizzard where I live right now!

Weather is not climate. Using this example as “proof” of the lack of AGW is about as valid as citing a particular heatwave as “proof” for it. That is, not at all.

Furthermore, global warming does not mean absolutely every place on Earth will on warm – due to heat redistribution, some places will warm much more than others, and some might even cool. For instance, the collapse of the ocean conveyor belt in the North Atlantic could theoretically plunge Europe in a new Little Ice Age.

Other objections

Not to worry. Though warming is happening, the IPCC is unduly alarmist since there are many negative feedbacks. Past changes were slow and we will adapt easily over the coming centuries. It will get warmer, nicer and crop yields will soar. And if not, there’s always geo-engineering.

Somewhat more intellectually valid…but still probably wrong.

As mentioned in #8, the IPCC is a slow, conservative institution that has up till now relied on conventional AGW models without accounting for potential catastrophic positive feedbacks (ocean acidification and the dessication of the Amazon rainforest removing vital CO2 sinks; melting permafrost and oceanic clathrates resulting in massive methane releases). Since Greenland and West Antarctica were recently found to be inherently much more unstable than previously thought, large-scale ice sheet collapse and inundations could occur over decades rather than the centuries and millennia projected in IPCC reports. Though there may exist negative feedbacks, such as a drier troposphere or increased cloud formation (yet even here the question of whether it will constitute a positive or negative feedback is poorly understood), they seem easily outnumbered by positively positive feedbacks.

There are plenty of examples of dramatic climatic shifts in Earth history. The Younger Dryas-Holocene transition 11,000 years ago consisted of a series of sudden jumps over a few years. Sea levels can also rise at rates far exceeding those needed for smooth human adaptation. Considering that greenhouse gas levels are rising at rates probably unprecedented in Earth history and that global dimming may have suppressed as much as half of the real warming (thus indicating that the climate sensitivity to CO2 levels used in conventional climate models is dangerously under-estimated), changes in coming decades are likely to be rapid and not for the better. Ocean acidification will finish off the world’s already depleted fish stocks and droughts in today’s temperate regions will break the world’s major breadbaskets; though agriculture can in principle be moved to Siberia and the Far North, the soils there are thin and acidic, and are unlikely to compensate in net terms.

Geo-engineering is, not surprisingly, rather risky – the climate system is not well understood, and fiddling with it could further worsen the problem. And not every country is expected to have absolutely altruistic aims when it comes to tweaking the world’s climate. Yet ultimately, for once we agree – I think it very likely that humanity will be forced into gambling with geo-engineering as the century unfolds. Perhaps climate stability is doomed and geo-engineering – in essense, humanity taking control of planetary ecological services previously provided for free – is already the only realistic choice left.

The hypocrisy of “Earth Day”, and other limp-wristed measures: the one issue where I find common ground with the deniers

Considering that there are 8760 hours in a year, turning off your lights for one of them is going to do absolutely zilch and is nothing more than an empty gesture of false atonement for one’s ecological sins; it is a kind of social placebo to delude people into thinking they’re doing something good for the environment, whereas in reality it is just an escape clause for guilt-ridden liberals that allows them to avoid making the real and initially painful changes society needs to attain long-term sustainability. As such, I join AGW-denying conservatives in boycotting this farce – albeit for obviously diametrically opposite reasons.

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