Response to Global Warming Denialist E-mail - Volcanoes and Global Cooling
Someone recently asked me to fact check an e-mail for them, so I've decided to post that response here. The e-mail was supposedly quoting Ian Plimer, a geologist and professor at the University of Melbourne, and a noted climate change denialist. For anyone interested, I've posted that e-mail in its entirety below the fold.
The lead-in to the body of the article was, "Where Does the Carbon Dioxide Really Come From?" After a bit of ranting about Priuses, CFL bulbs, and the like, it got to its main point - that volcanoes supposedly spew out far more carbon dioxide than any human contributions. It even made the claim:
...when the volcano 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.
Just a bit later, the e-mail claimed that the Earth has been cooling for the last century:
It's because the planet has COOLED by 0.7 degrees in the past century and these global warming bull artists got caught with their pants down.
So, in response to the person who asked me to fact check this e-mail, I responded in three parts, as detailed below.
On the first level of fact-checking, I didn't find the actual source of this quote from Plimer. All I could find were reprints of this e-mail. So, I'm not sure if he actually wrote it (and given the tone, I would hope not), but it does appear consistent with claims of his I've found elsewhere. As far as his background, that's simply copied-and-pasted from Wikipedia, so it's probably correct.
Volcanic Emissions vs. Human Emissions:
Plimer is way off base here. I found many, many different sites dealing with this. Here are two of the better ones:
- USGS - Volcanic Gases and Climate Change Overview
- Discovery News - Humans Dwarf Volcanoes for CO2 Emissions
That first link contains these two tables, so that you can compare annual volcanic CO2 emissions to human emissions. It also contained the emissions for a couple notable eruptions, Mt. St. Helens and Mt. Pinatubo. Annual human caused CO2 emissions are on the order of 134 times higher than total annual volcanic emissions (which includes submarine volcanos), and about 700 times higher than what was released by the one-time event of Mt. Pinatubo erupting.
|Yearly CO2 emitters||Billion metric tons per year (Gt/y)|
|Global volcanic emissions (highest preferred estimate)||0.26|
|Anthropogenic CO2 in 2010 (projected)||35|
|Light-duty vehicles (cars/trucks)||3|
|Approximately 24 1000-megawatt coal-fired power stations *||0.22|
|CO2 emission events|
|Mount St. Helens, 18 May 1980||0.01 Gt|
|Mount Pinatubo, 15 June 1991||0.05 Gt|
|Number of Pinatubo-equivalent eruptions equal to annual anthropogenic CO2||700|
|Number of Mount St. Helens-equivalent eruptions equal to annual anthropogenic CO2||3500|
I've seen similar claims of global cooling a few times before, but usually on shorter time scales. It almost always comes down to cherry-picking data. Here's an article dealing with a similar claim made by David Rose last year, and another article dealing with longer term trends.
- Skeptical Science - Misleading Daily Mail Article Pre-Bunked by Nuccitelli et al. (2012)
- Bad Astronomy - The Earth Is Warming Faster Now Than It Has in 11,000 Years
Below is a good graph from the first article. It clearly shows a long term warming trend over the past several decades. But it's not a perfectly smooth line, and there are outliers both above and below the general trend. So, if you cherry-pick, as they show in the animation, and choose an appropriate (or rather, inappropriate) time period, you can say there's been cooling over that short term period, and then naively extrapolate that short term cooling to saying that it's a long term cooling trend. But when you look at the larger data set over several decades, it's clear which way the trend is going.
The second article dealt with longer term trends, addressing the e-mail's specific claim of cooling over the last century. Below is a graph from that article, showing the temperature anomaly for the past 11,000 years. I clearly shows that the rate of change right now is much higher than it's been than at any other point in that period, and a clear warming trend for the past century.
So, this e-mail contained nothing but the bogus claims I've come to expect from the climate change denialists. I really don't understand this mindset. Problems don't disappear just because you ignore them. Burying your head in the sand won't make global warming go away. We've already had to face some consequences of a changing climate, and rather quickly, we're going to have to start dealing with the more profound effects. Why not own up to it and start working on solutions now?
For those interested, here is the full text of the e-mail I received. I cleaned up the formatting a bit, but tried to keep it pretty similar to what I received.
Ian Rutherford Plimer is an Australian geologist, professor emeritus of earth sciences at the University of Melbourne, professor of mining geology at the University of Adelaide, and the director of multiple mineral exploration and mining companies. He has published 130 scientific papers, six books and edited the Encyclopedia of Geology.
Born: 12 February 1946 (age 67)
Fields: Earth Science, Geology, Mining Engineering
Institutions: University of New England,University of Newcastle,University of Melbourne,University of Adelaide
Alma mater: University of New South Wales,Macquarie University
Thesis: The pipe deposits of tungsten-molybdenum-bismuth in eastern Australia (1976)
Notable awards: Eureka Prize (1995, 2002),Centenary Medal (2003), Clarke Medal (2004)
Where Does the Carbon Dioxide Really Come From? Professor Ian Plimer could not have said it better! If you've read his book you will agree, this is a good summary.
PLIMER: "Okay, here's the bombshell. The volcanic eruption in Iceland. Since its first spewing of volcanic ash 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. Of course, you know about this evil carbon dioxide that we are trying to suppress - it's that vital chemical compound that every plant requires to live and grow and to synthesize into oxygen for us humans and all animal life. I know....it's very disheartening to realize that all of the carbon emission savings you have accomplished while suffering the inconvenience and expense of driving Prius hybrids, buying fabric grocery bags, sitting up till midnight to finish your kids "The Green Revolution" science project, throwing out all of your non-green cleaning supplies, using only two squares of toilet paper, putting a brick in your toilet tank reservoir, selling your SUV and speedboat, vacationing at home instead of abroad, nearly getting hit every day on your bicycle, replacing all of your 50 cent light bulbs with $10.00 light bulbs.....well, all of those things you have done have all gone down the tubes in just four days. The volcanic ash emitted into the Earth's atmosphere in just four days - yes, FOUR DAYS - by that volcano in Iceland has totally erased every single effort you have made to reduce the evil beast, carbon. And there are around 200 active volcanoes on the planet spewing out this crud at any one time - EVERY DAY.
I don't really want to rain on your parade too much, but I should mention that when the volcano 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. Yes, folks, Mt Pinatubo was active for over One year - think about it. Of course, I shouldn't spoil this 'touchy-feely tree-hugging' moment and mention the effect of solar and cosmic activity and the well-recognized 800-year global heating and cooling cycle, which keeps happening despite our completely insignificant efforts to affect climate change. And I do wish I had a silver lining to this volcanic ash cloud, but the fact of the matter is that the bush fire season across the western USA and Australia this year alone will negate your efforts to reduce carbon in our world for the next two to three years. And it happens every year. Just remember that your government just tried to impose a whopping carbon tax on you, on the basis of the bogus 'human-caused' climate-change scenario. Hey, isn't it interesting how they don't mention 'Global Warming' anymore, but just 'Climate Change' - you know why? It's because the planet has COOLED by 0.7 degrees in the past century and these global warming bull artists got caught with their pants down. And, just keep in mind that you might yet have an Emissions Trading Scheme - that whopping new tax - imposed on you that will achieve absolutely nothing except make you poorer. It won't stop any volcanoes from erupting, that's for sure. But, hey, relax......give the world a hug and have a nice day!"