A Response to Climate Change Sceptics
This is not an account of the latest, very contorted international negotiations over climate change. Nor is it about the Rudd Government’s rather dismal progress on climate change policy so far. If it was, I’d have chosen a different title.
This short essay is a general response to ‘climate change critics’, also known as ‘climate change sceptics’ and ‘climate change deniers’. For reasons I explain, I prefer to say ‘climate change gamblers’.
Sceptics may well regard me as biased, because I worked for several years as an environmental activist in the past. But these days I work for no interest group and speak for myself alone. I write this simply as one human being to others. I do invite comments and criticisms.
I began lobbying for action on greenhouse emissions about two decades ago. I remember a session with a senior politician in his Canberra office during the late 1980s.
His reply to my initial pitch was what seems to me the basic case of ‘climate change scepticism’ to this day. It was an argument along these lines:
“there’s no SOLID evidence that human-induced global warming is really happening, so it’s unwise to take action that might have negative economic impacts”
My reply to him at the time was that he’d missed the point.
I tried to summarize what I meant:
- We know there’s been a STRONG correlation in the geological past between CO2 levels and global temperatures.
- We ARE increasing the level of CO2 in the atmosphere – and the level of other important greenhouse gases. These measurable and quite rapid changes are not in dispute.
- Given (1) and (2), the rapid changes were are bringing about in our atmosphere’s composition clearly has the POTENTIAL to cause devastating global changes to our climate. Of course, we don’t know the future with certainty, but we CAN reasonably infer that increasing levels of greenhouse gases increases the RISK of devastating climate change. At the very minimum, there’s no evidence to the contrary.
- We only have ONE habitable planet
- It’s highly risky to conduct a gigantic, uncontrolled experiment on the whole of humanity’s habitat.
- Even if there are economic downsides to achieving atmospheric stability, they’re offset by potential economic gains; in any case, they’re trivial compared with the potential costs of rapid climate change.
Twenty years later, I see no reason to change any of these propositions.
Personally, I very much hope ‘climate change sceptics’ are right.
I would like few things more than to discover we are NOT in imminent danger of doing yet more ecological damage to this planet on a massive scale (we’ve done more than enough already!)
I just wouldn’t take that risk.
I wouldn’t take a potentially-fatal risk like that with a house block, or a hamlet, or a city or a nation – let alone with the whole planet!
I believe we have quite enough grounds for action to stabilize the atmosphere. We’ve had them for two decades… and counting. At the very least, we should take action to stablize the atmosphere until we understand how this complex global system really works.
Several assertions made frequently by ‘climate change sceptics’ are highly misleading.
There are claims, for example, that pressure is routinely applied from the top of the International Panel on Climate Change to establish a scientific consensus that supports the ‘alarmist’ case. In other words, it’s claimed that only alarmist views get a decent run.
That’s nonsense. I looked at just one aspect of the 4th IPCC report in some detail, to try to better understand the sea level rise issue. I wanted to know why IPCC 4 actually reduced the estimate for sea level rise from the prediction in IPCC 3 (published seven years earlier).
What I learnt horrified me and I wrote this unashamedly alarmist article in a local North Queensland blog partly as a result.
The case of sea level rise emphasizes one of my key concerns. Just as the current climate change scientific consensus may be far too alarmist (a possibility I can accept and would welcome if true), it also follows that it may be far too reassuring.
I also dispute claims there is systematic enforcement of alarmist conformism on the issue of climate change – and punishment of dissenters.
This may apply in some university and government departments, but there are many where it doesn’t. Actually, generous funding is still available for those who wish to make a career out of skepticism in this field.
This is in stark contrast to disputes where significant sanctions – up to and including imprisonment – actually are imposed on dissident opinion. The quintessential example of this is lingering controversy over the events of World War Two. Use of the term ‘climate change denier’ is especially inappropriate, as it suggests climate change skeptics may be punished in an equally draconian way. There’s no evidence this has ever occurred.
There is a real danger, in my opinion, that these precious years when strong, effective and relatively pain-free action on emissions reduction is possible, will be squandered over narrow debates about whether the temperature really is peaking, whether polar bears truly are dying off, the significance of an unusually cool winter in Europe or the full impact of solar cycles on the planet’s climate.
I believe all these discussions, while of some interest and relevance, distract from the bigger picture.
It puts my back up when people say “we must accept … X, Y or Z”… Why accept anything? The answer is there’s no need to accept anything at all without evidence. But when there is compelling evidence, stubborn non-acceptance can damage your health. Someone who refuses to accept good evidence that a truck is heading his way may well get run over.
Even though there are many issues that remain to be debated and worked out in detail, I do believe there’s actually quite a lot of consensus over some basic issues surrounding climate change.
I’ve set them out below in a series of “we must accept” propositions. If I’m right about these, we’re really only one step away from sufficient consensus to take decisive action.
Here goes:
- We must accept that human impact on the planet – in our era – is so great that it is causing measurable and rapid changes in atmospheric composition. In particular, the levels of greenhouse gases such as CO2 are rising fast. (See Chart Three below, sourced from a ‘climate sceptic website. Sharp greenhouse gas increases are not in dispute).
- We must accept a close past correlation between the atmospheric concentration of greenhouse gases and temperature variation. (See Charts One and Two below. Accepting this may be a problem for Creationists who believe the world is only a few thousand years old, but for the rest of us, the geological evidence for this correlation is clear)
- We must accept that we don’t really know the consequences of what we’re doing to the atmosphere. We’re making major changes and cannot possibly be sure of the consequence. (Only the most egocentric modelers or delusional fools believe they really understand the multi-faceted issue of climate well enough to predict the future with certainty).
- We must accept that there’s only one planet available for humanity. (A habitable planet, that is – in this part of the universe).
That’s quite a lot of consensus, really. There’s only one more step and we’re all on the same page.
Collectively, we face a moral decision. Will this generation of humanity accept a moral obligation to AVOID taking potentially catastrophic risks with the only habitat that can sustain our descendants?
I think we should. What do you think?
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CHART ONE: VARIATION IN TEMPERATURE AND CO2 LEVELS OVER THE LAST 700,000YEARS (source: New Scientist)

CO2 and Temperature Variation - the Last 700,000 Years
CHART TWO : VARIATION IN TEMPERATURE AND CO2 LEVELS OVER THE LAST 20,000YEARS (source: Global Warming FAQs)

Global Carbon Dioxide and Temperature Levels since the end of the last Ice Age
CHART THREE : VARIATION IN CO2 LEVELS OVER THE LAST 1,000YEARS (source: Maybeitsnotwarming.com)

1,000 Years of Global Carbon Dioxide Change
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Notes on the Charts
The very close correlation over geological time between CO2 and temperature, shown in Charts One and Two, was already obvious two decades ago. There’s plenty more evidence now to support the correlation. However, it’s also become clear that on occasions CO2 has lagged temperature – leading some sceptics to suggest that CO2 is only a consequence, not a cause, of temperature variation.
A detailed discussion of this topic is beyond the scope of this article. However, CO2 has correlated closely with temperature in the past. We don’t fully understand the role it plays in the climate. As Chart Two above makes clear, modern industrial society has begun to push this variable sharply upwards – along with other greenhouse gases.
Chrat Three brings this spike in Co2 into even sharper focus. At current rates of greenhouse gas increase, the aggregate greenhouse forcing effect will saor.
Overall, I believe the key propositions set out in this essay hold. They held 20 years ago. From my perspective – as someone not willing to gamble the planet – these have been two decades of mainly wasted opportunities.
‘Climate change gamblers’ propose taking a chance that highly elevated levels of CO2 and other greenhouses gases will NOT trigger severe climatic instability. It’s a risky bet. They’re not called ‘greenhouses gases’ for nothing!
Given the past correlation between CO2 and temperature and our basic knowledge of the action of greenhouse gases in the atmosphere, I think that’s an extreme level of recklesness.
We give ourelves the name ‘Homo sapiens’. This may be the first and only test of whether we’re just flattering oursleves.
What wise species gambles its entire habitat on a hunch?
(Note: This article is also published on the Agmates website)