@mark_lynas The graph is sloppy, but Lomborg is more correct than you allow. North America was hit by multiple catastrophic fires in 1870-1920, beginning w the Peshtiga fire of 1871 that killed 1500-2500 ppl. This led to a bunch of (in retrospect) bad decisions. 1/8
@mark_lynas First, a policy of fire suppression that *still* is being observed, which caused a vast buildup of burnable material in western forests throughout N America. The Bambi syndrome is a huge contributor to fires to this day. 2/8
@mark_lynas Second, massive replanting of burned areas w/ monocultures (e.g., Northern pine for fenceposts), leading to big even-aged stands of trees. These are reaching natural senescence, which makes them much more vulnerable to fire than mixed stands would be. 3/8
@mark_lynas (These and other silvicultural factors were not taken into sufficient consideration by the PNAS team, I would argue.) 4/8
@mark_lynas Third, fire suppression led directly to uncontrolled human movement into fire zones, which increased vulnerability to fires. The Carr fire now in CA is <200 sq mi, a tiny fraction of early 20th-c fires, but it has caused horrible damage. 5/8
@mark_lynas Fourth, the aging, even-aged stands are vulnerable to exotic insect attacks, which has led to a huge buildup in western forests of dead wood—more fire fuel. 6/8
@mark_lynas Is climate change a factor? YES—especially in lengthening the fire season. But it is difficult to disentangle from these other factors and may well be much smaller. 7/8
@mark_lynas But even if climate change were solved, we would still have even-aged tree stands, giant fuel buildups from fire suppression, exotic insect plagues (though probably they would have less impact), and expansion into fire zones. We’d still have a huge fire problem. 8/8
