One of the difficulties of understanding climate change is that it's hard to see it for yourself. The data tells an interesting story, made more interesting by the output of the climate models. But at a visceral level, numbers have a different status in our minds than personal experience.

In September 2002 I drove with Mom and Dad to the Grand Canyon, driving through places I've been visiting since I was a kid. I saw the dead trees. They registered.

Now, we know drought kills trees. And we know drought's been happening on its own here for the entire chunk of the Holocene that we can see through the tree ring record. So I was, in my own mind, having a visceral experience of drought, not any deeper sort of climate change. But peeling the onion back a layer, I've come to the realization that more than a simple drought cycle may be at work here, that the warming that has clearly been measured here is playing a role.

It is only in hindsight that we will know whether what I'm seeing now, here on the landscape of the desert southwest, is Climate Change or simply a manifestation of natural decadal-scale variability. That's the hard thing about the experience of Climate Change - it involves processes over time scales sufficiently long that our own experience may not be the best guide.

But I've sure seen a lot of dead trees, and they've made me mighty curious. Stuff I wrote elsewhere about this, on climate and New Mexico's dying trees:

FRIJOLITO MESA— Craig Allen's trees are dying.

The ponderosa pines are gone completely from this patch of wilderness, and piñon are not far behind.

Insects have been the executioners, but warming temperatures and drought appear to have pronounced the death sentence, pushing trees to the brink for the bugs to finish off.

Allen, a 46-year-old federal biologist, has been studying the Jemez Mountains for more than two decades. He counts and measures the trees, tracks the growing grass and measures the dirt washing down the gullies, all in an effort to understand the complex interplay between climate and landscape.

Over the past two years, the one-two punch of warm weather and drought has brought extraordinary change.