Volcanoes, Carbon Dioxide and Hot Air

Striking back at an old chestnut ...

Normally I don’t waste my time responding to climate denier garbage, but after last week’s post, a friend passed on some quotes from an Australian mining geologist named Plimer regarding the importance of mankind’s CO2 emissions. He argued that volcanic emissions are much more important (at least he does seem to acknowledge - unlike some deniers - that increased CO2 does lead to increased temperatures). My friend asked for my opinion.

So, here it is …..

The man’s a well-known and discredited climate skeptic with vested interests in mining, which (coincidentally?) is the big loser in efforts to curb climate change. I’ve added brief responses below to the whoppers my friends forwarded to me.

PLIMER: “The volcanic eruption in Iceland.  Since its first spewing of volcanic ash, it has, in just FOUR DAYS, NEGATED EVERY SINGLE EFFORT you have made in the past five years to control CO2 emissions on our planet - all of you.”

THE TRUTH: Like a lot of climate-denier propaganda, Plimer’s statement contains a grain of truth immersed in an ocean of obfuscation. The truth is that we’ve done far too little to curb greenhouse gas emissions - due in no small part to misinformation campaigns from vested interests. While every bit helps, the problem is just too big to be solved at an individual level. Meaningful reductions will require buy-in from government and industry. The big lie is the implication that volcanoes are the problem.

It’s worth having a look at some of the numbers.

The world’s fossil fuel burn contributes 36 billion tons of CO2 to the atmosphere each year. Most of it is from just a few countries: about 10 billion tons from China, 5 from USA, 3 from India, 2 from Russia, ….

The global average CO2 emission rate per person is about 5 tons per year. That’s less than one third of the average for Aussies or North Americans - and for Kiwis if you count our warming contribution from from agricultural emissions like methane and nitrous oxide.

If ‘just’ the billion or so people in the richest nations (including the EU, UK, USA, Canada, Japan, Australia and New Zealand) were to cut their emissions by 10 percent, the global reduction would be about 1 billion tons of carbon. That would be a hugely useful outcome, particularly if similar reductions could be sustained year on year.

That modest reduction is also about four times more than the total annual emission from all the world’s volcanoes. They aren’t the problem. All three relevant agencies in the USA agree that anthropogenic emissions of CO2 exceed those from volcanoes by more than a factor of a hundred. Simply put, while greenhouse gas emissions from volcanoes currently account for less than 1 percent of those from fossil fuel combustion, we’re responsible for the other 99 percent of the problem.

I think the Icelandic volcano Plimer refers to may be Katla, which is thought to be the world’s largest volcanic emitter of CO2, and was recently found to emit a lot more than previously thought. The new estimate is up to 24 kilotons/day, which corresponds to about 0.009 billion tons per year. Still tiny compared with the 36 billion tons we’re responsible for. And it would remain insignificant even if there were hundreds of similar volcanoes.

It’s worth noting that there have been times in Earth’s long history when emissions of CO2 from volcanoes have indeed been much higher. The most recent was millions of years ago, long before the emergence of mankind. Those historically high burdens of CO2 of course led to warmer temperatures, and sea levels elevated - due to a variety of factors - by around a hundred metres (less concerning for dinosaurs than modern-day humans). Such natural changes will no doubt continue, but they are much slower, and are beyond our control. That’s not the case at present. We now have an additional problem of our own making - and it’s rapidly moving in one direction. The increases we’re seeing today are ‘almost certainly’ (I’d say ‘indisputably’) due to fossil fuel burning.

PLIMER: Mt Pinatubo erupted in the Philippines in 1991, it spewed out more greenhouse gases into the atmosphere than the entire human race had emitted in all its years on earth.

THE TRUTH: Plimer is just plain wrong. It didn’t, as is obvious from an inspection of the time series of CO2 measurements from Mauna Loa Observatory in Hawaii (and elsewhere), which show no sign of any discontinuities that could be attributed to such eruption effects. If his statement were true, there would be a huge step increase of CO2 in 1991. There wasn’t.

The reason you don’t see a step then is because the CO2 output from the eruption of Mount Pintatubo was only 0.05 billion tons. While that may sound large, it pales into insignificance compared with ‘our’ 36 billion tons per year.

Finally, it’s no coincidence that there’s a close parallel between increases in atmospheric CO2 and our increasing demand for fossil fuels. By contrast, there’s no such parallel with volcanic activity.

PLIMER: isn't it interesting how they don't mention 'Global Warming' anymore, but just 'Climate Change. It's because the planet has COOLED by 0.7 degrees in the past century.

THE TRUTH: Wrong again. As I’ve discussed in previous posts, global temperatures have increased by 1.1C, and the amount of heat stored in the oceans due to infrared trapping in the air above is increasing at the same rate as adding the energy released from the detonation of 5 Hiroshima bombs per second.

But it’s not just about warming. It’s also about increased severity of weather events, changing rainfall patterns, and sea level rise. And the severity and extent of bushfires, which also provide a significant positive feedback. The Australian bushfires last year effectively doubled the country’s annual carbon emissions.

Plimer-like peddlers of misinformation on climate change have already done the world and future generations a huge disservice. Fortunately they’re always old curmudgeons who are well past their use-by date, so their fate (like mine ☹) will be sealed soon by attrition. But is it already too late to avoid the future havoc they’ve wrought? Concerted political action is long overdue, and desperately needed. It will take inspirational non-partisan leadership from the superpowers. With sanity at last restored to The White House there’s cause for renewed hope.

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