Been arguing with a climate change sceptic but get flummoxed by all those pesky CO2 level stats? Been caught without your medieval warming cycles graphs? Suspect that your beach house may be underwater by 2080 but not up on rising sea levels lingo?  

Environmental News and Commentary publication Grist has the answer — a handbook on How to Talk to a Climate Sceptic. Grist has sourced several leading climate scientists and studies to provide an answer to every sceptical argument in the book.

The guide lists rebuttals to popular naysayer lines like “What’s wrong with warmer weather?”, “It’s the sun stupid”, “Greenland used to be green”, “Mars and Pluto are warming too” and our favourite, “It’s cold today in Wagga Wagga.”

Of course, in the interests of stirring the pot (read: picking a fight), we’ve been itching to try it out on someone.

Enter Daily Tele columnist Piers Akerman, who writes today:

What Al Gore, the EU, the UN, Garrett and Rudd all choose to ignore is the science which shows that the Earth’s climate has always been variable and that climate change can be attributed to many things, but that among the least likely to have had any influence is human activity.

Akerman continues:

Professor Ian Plimer of the School of Earth and Environmental Sciences at the University of Adelaide says the current theory of human-induced global warming is not in accord with history, archaeology, geology or astronomy and must be rejected.

Further, he says, the current promotion of this theory as science is fraudulent and the current alarmism on climate change is not science.
Some 96% of the greenhouse effect is due to water vapour, the rest is due to CO2, methane and other gases, he says.  

Grist says:

Objection: H2O accounts for 95% of the greenhouse effect; CO2 is insignificant.

Answer: According to the scientific literature and climate experts, CO2 contributes anywhere from 9% to 30% to the overall greenhouse effect. The 95% number does not appear to come from any scientific source, though it gets tossed around a lot.

Please see this paper (PDF), the textbook referenced here, and this article at RealClimate.…

Read more here.

Akerman continues:

Of the CO2, 95% is due to natural processes (volcanoes, plants, bacteria etc) with the remainder (about 0.1%) resulting from human activities.

Grist says:

Objection: It’s clear from ice cores and other geological history that CO2 fluctuates naturally. It is bogus to assume today’s rise is caused by humans.

Answer: We emit billions of tons of CO2 into the air and, lo and behold, there is more CO2 in the air. Surely it is not so difficult to believe that the CO2 rise is our fault. But if simple common sense is not enough, there is more to the case. (It is worth noting that investigation of this issue by the climate science community is a good indication that they are not taking things for granted or making any assumptions — not even the reasonable ones!)

It is true that CO2 has gone up on its own in the past, most notably during the glacial-interglacial cycles. During this time, CO2 rose and fell by over 100 ppm, ranging between around 180 to 300ppm. But these rises, though they look steep over a 400Kyr timeframe, took 5K to 20Kyrs, depending on the glacial cycle…

(read more here.)

And on the Volcano point, Grist says:

Objection: One decent-sized volcanic eruption puts more CO2 in the atmosphere than a decade of human emissions. It’s ridiculous to think reducing human CO2 emissions will have any effect.

Answer: Not only is this false, it couldn’t possibly be true given the CO2 record from any of the dozens of sampling stations around the globe. If it were true that individual volcanic eruptions dominated human emissions and were causing the rise in CO2 concentrations, then these CO2 records would be full of spikes — one for each eruption. Instead, such records show a smooth and regular trend.

Read more here.

But wait, says Akerman:

Even if humans stopped producing CO2 now, it would not make the slightest difference to atmospheric CO2, as natural sources swamp the human sources. Even so, the atmosphere is almost at the lowest level of CO2 content of the past 4550 million years, and the role of the greatest biomass on Earth bacteria and CO2 is an unknown.

Grist says:

Objection: According to the IPCC, 150 billion tonnes of carbon go into the atmosphere from natural processes every year. This is almost 30 times the amount of carbon humans emit. What difference can we make?

Answer: It’s true that natural fluxes in the carbon cycle are much larger than anthropogenic emissions. But for roughly the last 10,000 years, until the industrial revolution, every gigatonne of carbon going into the atmosphere was balanced by one coming out.

What humans have done is alter one side of this cycle. We put approximately 6 gigatonnes of carbon into the air but, unlike nature, we are not taking any out.

Read more here.

We’re happy for you to prove Grist wrong on this — so send your objections to boss@crikey.com.au.