It is hard to square Leighton Steward’s cheery message with the vast swaths of dead trees across the mountains of northern New Mexico.
“Fall of ’02 is when they started to die,” biologist Craig Allen told me a few years ago as we walked through a forest of piñon corpses in the Jemez Mountains.
The years 2002 and 2003 were very warm and very dry in the mountains of northern New Mexico. It’s been this dry here before, but this time around far more trees died. Why?
When Allen and a group of colleagues crunched the numbers, they noticed that, like much of the globe, New Mexico has been warmer in the 21st century than it has been since we’ve been measuring.
It was bark beetles that finished off the trees, but it was the heat of the drought of 2002-03 that made the difference between a garden-variety drought and the massive forest die-off, the scientists concluded.
Scientists say the reason for the warming is rising levels of greenhouse gases, especially carbon dioxide from the tailpipes of our cars and factory stacks. That heat, Allen and his colleagues concluded, explains the widespread tree death.
So why does Steward, a charming 74-year-old Texan, say carbon dioxide emissions are a good thing?