We still seem to be in a weak la Nina, and all the usual bushfire warnings are out. No doubt we will have some fires too. My attention was caught on Judith Curry’s website by a reference to a piece (abstract only) in Nature on the incidence of wildfires in the last two thousand years. The authors used sedimentary charcoal as the evidence and suggest that global biomass burning declined from AD 1 to ?1750, before rising sharply between 1750 and 1870. Global burning then declined abruptly after 1870. The early decline in biomass burning occurred in concert with a global cooling trend and despite a rise in the human population. We suggest the subsequent rise was linked to increasing human influences, such as population growth and land-use changes. Our compilation suggests that the final decline occurred despite increasing air temperatures and population. We attribute this reduction in the amount of biomass burned over the past 150?years to the global expansion of intensive grazing, agriculture and fire management.
The last sentence strikes me as most interesting. We manage the land much better than in the past (of course, there are more of us to manage, and managing the land is a widespread activity everywhere, because of agriculture). But at least in urban Australia we expose more people and properties to fire by allowing development in bushland areas…
Later: for Chris, who agonises over the lack of December data from UAH. Here it is:
Now trends don’t mean much for the future. They only tell you want has happened where there are data. But if this pattern were to continue for the rest of the century (and I don’t suggest for a moment that it would), the increase would be of the order of 1.28C degrees.