One of the false impressions created by global warming doomsayers is that the recent warming that we’ve experienced (how great this warming actually has been and how much can be attributed to human activity remains unclear) is unprecedented and therefore poses urgent risks to humanity that must be addressed with immediate and drastic actions. The truth is that that the climate is always changing and some of these changes in the past have been far greater and more impactful than anything we’re experiencing currently.
In Saturday’s WSJ, Matt Ridley wrote on Volcanoes, Iceland and Natural Climate Change (sub req):
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 days...by 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.
Ridley’s key point is that while a lot of time and energy has been spent speculating about the impact of manmade warming and how to reduce and mitigate its impacts, little thought has gone into preparing for naturally created warming/cooling scenarios. There’s much more history on the latter type of climate change and, judging by previous periods of such change, the potential impacts on humanity are far greater. While we’re obsessed with the three percent of carbon we put into the atmosphere and how it may be warming the planet, we tend to ignore the natural causes of climate change which likely carry much higher risks for us. If the past is any guide, at some point the forces of nature will once again humble man.