Saturday, March 24, 2012

Summer in Spring 2012

"This March, we started with twelve days of April weather, followed by ten days of June and July weather, with nine days of May weather predicted to round out the month"
image from Dr. Jeff Masters

Monday, March 19, 2012

Pleistocene Climate Change Context

A roadmap of the last 50,000 years helps put the modern global warming in context:

This awesome graph, and many others, can be found here. Includes a good discussion of the Eemian interglacial and other interglacials in comparison with the modern Holocene.

Sunday, March 11, 2012

Catestrophic Fire in the West

What if wildfire risk were catastrophically worse than we have imagined? Dr. Littell (University of Washington) walks us through just such a scenario in this USFS webinar. He starts by pointing out that the recent increase in wildfire area is not unprecedented. The traditional story has been that large "mega-fires" have increased in recent years, but Littell's reanalysis and recalculation of historical records found that the natural fire regime from 1910-1940 may have matched the last thirty years of large fires. (cf: The Big Burn) In both time periods perhaps 97% of the area burned was the result of less than 3% of the fires, the mega-fires.
Dr. Littell considers whether the dip in the middle is actually due to the triumph of fire suppression, or whether it is climatically driven:

What happens if it gets even warmer? Littell goes on to calculate fire probabilities based on temperature and precipitation and projects the results in a model of a 1 degree C climate change future:
Percentage Increase in Area Burned with +1C. White areas did not have a significant relationship between area burned and temperature.

7 types of Igneous Rocks

Fire Burns Hotter After Absense

Reintroducing fire to long-unburned Southeastern Pine Savannas can kill the "fire dependent" Long Leaf Pine while sparing fire sensitive species that have invaded the Savanna. It seems the pines loose their adaption to fire over time. Their roots grow into the thick duff layers of pine needles they themselves produced. When a fire finally starts, either by accident or through restoration efforts, the usual wave of fast-moving "scorching" flames are followed by a second, deadly wave of smoldering fire in the deep pine duff. The duff is thickest around old pine trees so the smoldering fire preferentially kills older "fire dependent" trees.

The human health effects of smoldering fires are also much worse than open flames.

Varner et al 2005 Restoring Fire to Long-Unburned Pinus palustris Ecosystems: Novel Fire Effects and Consequences for Long-Unburned Ecosystems