The Hot Zone

Sizzling Hot

Posted by Alison Hawkes on May 28, 2010
Category : Climates of the Past

Massive wildfires that cause untold destruction of life and habitat are becoming a feature of modern climate change. A mere 1.8 degree jump in temperature is predicted to equal a 40 percent increase in lightening, the main ignition source of natural fires. We already get some 8 million strikes a day under modern atmospheric conditions. It’s becoming sizzling hot here on Earth.

Greece has been hit with massive wildfires in recent years. Photo courtsey of NASA, 2009

Greece has been hit with massive wildfires in recent years. Photo courtsey of NASA, 2009

Foothills of NASA's Jet Propulsion Lab in Pasadena, California, 2009. Courtesy of Brent Buffington, JPL

Foothills of NASA's Jet Propulsion Lab in Pasadena, California, 2009. Courtesy of Brent Buffington, JPL

New research into the past is backing up modern day observations. In a paper published in May in Nature Geoscienc, researchers at University College Dublin and colleagues tracked down climate and fire conditions from 200 million years ago during a major environmental transition period in Earth’s history – the Triassic-Jurassic boundary.

During this period, massive volcanism broke apart the super-continent of Pangaea and spiked CO2 levels from 600 to more than 2,100 parts per million by volume. For comparison, Earth’s current CO2 concentration is about 391 ppmv, an all time high for recent history. The resulting mass extinction gave way to our most imaginative period in paleo-history – the age of large dinosaurs. Common, too, emerged the conifers – woody plants with thin needles and seed-bearing cones.

What the researchers found was that as CO2 spiked, so did the number of fires. They looked at about 15,500 fossil charcoal particles from this time period in East Greenland and discovered a five-fold increase in charcoal abundance during peak CO2 levels. The vegetation also appeared to be changing. As temperatures rose, broad-leafed plants died off and were replaced by narrow-leafed varieties.

These narrow-leafers were able to withstand higher temperatures, but were also more prone to burn because they contained less moisture. Just think of the last campfire you built – what do you throw in to really get it going? Pine needles.

The researchers suspect a positive feedback loop emerged. As more lightening struck, the ignition rates and spread of wildfires increased due to the burn-prone vegetation, which then released more carbon back into the atmosphere and exacerbated the conditions even more.

Coutesy of NOAA photo library

Coutesy of NOAA photo library

What this says about modern day climate change is informative. All that fiery turmoil during the Triassic-Jurassic boundary happened with a temperature change of about 7 degrees Fahrenheit.

-Alison Hawkes

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