Saturday, August 6, 2011

Matt Ridley on Volcanoes, Iceland and Natural Climate Change

Will Volcanoes Cool Our Warming Earth?


I spent part of last week in Iceland, where the fragility of civilization's veneer is all too evident in a violently volcanic landscape. Whereas in most countries geology amazes you with its age, in Iceland it stuns you with its youth. The country lost an offshore island in 1830 and gained one in 1965. Lava from recent centuries is everywhere; rivers diverted by eruptions are still carving valleys just a few thousand years old. The coastline moved by three miles after the eruption of the Katla volcano in 1918.

That was Katla's last big eruption, and it is due for another. Its usual interval is less than 80 years, sometimes following the eruption of its smaller neighbor, Eyjafjallajökull, which was the villain of 2010's airplane-grounding ash cloud. A bridge on the country's main road was washed away on July 9 by a flood of glacial meltwater flowing from under the ice cap that covers Katla, so the big one may be coming. Hekla, which goes off every 10 years or so, is also overdue. Grimsvötn, an even more regular erupter, blew a hole in Europe's biggest ice sheet in May.

The Laki fissure's eruption in 1783 spewed out so much sulfur dioxide and hydrogen fluoride that it poisoned 80% of Iceland's sheep, covered northern Europe in thick smog for a month and caused crop failures that starved perhaps six million people. An exceptionally harsh winter ensued all over the northern hemisphere.

The possibility of another Katla or Laki reminds us of the need to prepare for dangerous climate change of the natural as well as the man-made variety. Abrupt climate change has been a sporadic feature of history since long before the industrial revolution, mostly in the form of cooling caused by volcanoes. Some three decades after Laki, 1816 was known as the "year without a summer" thanks to a big eruption in Indonesia. Even Mount Pinatubo in the Philippines in 1991 caused a brief, though small, drop in world temperatures.

Other abrupt coolings have been bigger but less explicable. Earlier this year, two scientists from Brown University used lake sediments to conclude that the sharp cooling in Greenland during the late Middle Ages, which extinguished the Norse colonies, saw temperatures drop by seven degrees Fahrenheit in 80 years, much faster than recent warming there. Conversely, Greenland's temperature shot up by around 13 degrees in 50 years as the world came out of the last ice age 12,000 years ago and the ice sheets of North America and northern Europe retreated—again, unlike today's slow increase.

Preparing to meet risks posed by nature does not exonerate human pollution. Earlier this year, after Grimsvötn erupted, a message went viral on the Internet, arguing that "the volcanic ash emitted into the Earth's atmosphere in just four that volcano in Iceland has totally erased every single effort you have made to reduce the evil beast, carbon."

If true, this is because carbon-reduction efforts are so far largely ineffective, not because volcanoes put out a lot of carbon dioxide. Total volcanic carbon-dioxide emissions, at up to 230 million tons a year, are less than 1% of fossil-fuel emissions of 32 billion tons a year. The Australian climate skeptic Prof. Ian Plimer argues that this probably understates the contribution of undersea volcanoes, but few other geologists agree.

But then the total carbon-dioxide emissions from biological sources—animals, plants, fungi and microbes—dwarf those from fossil fuels and amount to some 800 billion tons a year. So although it is a myth that volcanoes produce more carbon dioxide than fossil fuels do, the natural world far outpaces our cars and factories. Roughly 97% of the carbon dioxide entering the atmosphere each year is from nature, not human activity.

Savage lurches in the global climate will happen one day, whether by manmade warming or volcanic cooling. Cutting carbon emissions might mitigate the former, but it will not help us, and may even hinder us, in adapting to the next Katla or Laki.


  1. Climate Change is NATURAL and CO2 is LIFE.With CO2 being 0.0390ppm of the atmosphere and mankinds contribution to all CO2 production 3% its all a little out of proportion don't you think. Atmospheric CO2 has been as high as 4,000ppm and life flourished on Earth and worrying about 0.0390ppm is a little over the top.

  2. This site blazons its intention to not explain science, but rather to make cherry picked data the servant of ideology with the RSS temperature record across the top of the article. As the authors well know, it is chosen to commence at the peak of the strongest El Nino on record, and to finish not with current data, but at the peak of one of the strongest La Nina's of recent years. Even such cherry picking to create a misleading impression is not enough for him. He also chooses a satellite record, which as he must know, accentuates the recorded effects of ENSO cycles on the data.

    Even with so carefully cherry picked end points, it is remarkable how flat is the temperature trend in the intervening years. What the authors have done is the logic equivalent of chart the a trend of the path taken by a swing from the peak of its arc to the lowest point, to deduce a falling trend. Even so, an embarrassingly for them, the trend tracked is flat. Plainly, if the trend was taken over the full cycle, the trend line would not be flat but rising. (a point that has been proven by Tamino).

  3. 1) Right, the satellite record is biased and should not be shown, since the surface record is much better with urban heat island bias producing a nice fake warming trend

    2) The header graph is updated once a year in February. All four global datasets since 1979 up to the present have always been posted right over there for anyone to look at -------->

    3) Even your fellow warmists admit in peer-reviewed research that the globe has not warmed since 1998, supposedly due to Chinese coal, or maybe volcanoes, or [insert new theory that doesn't conflict with the null hypothesis]. Those incompetent cherry-pickers who blazon their intention to not explain 'science'!

  4. Planet Earth is ‘more sensitive to carbon dioxide than we thought’

    If carbon dioxide emissions continue at their current rate through to the end of this century, atmospheric concentrations of the greenhouse gas will reach levels that existed about 30 million to 100 million years ago, according to Jeffrey Kiehl from the US National Centre for Atmospheric Research (NCAR).

  5. Planet Earth is much less sensitive to CO2 than we thought

  6. just out today:

  7. Who is "MS"? Why should anyone care what he/she has to say about climate science?

  8. Who I am is confidential and irrelevant. Evaluate my posts on their scientific merit only. Appeal to authority is often fallacious, as proven time and again in the climategate saga.