Tree Line

In the late 1990s, I was on a group hike that nearly ended in disaster. About a dozen of us were above tree line on a mountain just as a thunderstorm threatened to move in. Our goal was to reach a small lake near the top, but the thunderstorm made it too dangerous to continue. A handful of people insisted on going anyway. Since it was an organized hike, the entire group needed to return to the trailhead together, so the rest of us waited at an abandoned mine so the others could find us when they returned from the lake.

We hunkered down in what little cover we could find just as the thunderstorm moved over us and began dumping torrents of rain. In the distance, we saw a couple of people become trapped on a rock face, and we were soon joined by a larger group of hikers who were less prepared than we were. We assisted the newcomers and debated just how safe we really were. The storm was bigger than we hoped, and it became clear to most of us that the risk of staying was too great. During a brief lull in the rain, we and the newcomers made a dash for the trees. Luckily, the rest of our group had made the same decision, abandoning their trip to the lake, and joined us at tree line. After hiking down the mountain as fast as possible, we encountered emergency vehicles waiting for the hikers we had seen on rock face.

I was reminded of this story recently as more bad news came in about humanity's sabotage of natural systems. Honeybees, critical to the survival of plants, are losing habitat because of climate change. Meanwhile, scientists have documented a mass die-off of seabirds that suggests serious problems with ocean ecosystems. Catastrophic seal level rise may now be inevitable, again due to climate change; and a new study indicates that we humans are critically reducing the collection and availability of energy necessary for ecosystems – and us – to function.

Like hikers determined to get as far above tree line as possible, we have defined "progress" as distance from Nature. We have done the equivalent of cutting down trees to fuel our ascent, altering the weather in the process and spawning the thunderstorm that threatens to maroon us, and then kill us. Heading back down the mountain is perceived as an act of cowardice, giving up on our dreams; so some people go ahead, while others compromise by waiting in the brush just above tree line until they come to their senses. Meanwhile, the risk is growing that lightning will cause the remaining trees to burn, cutting off escape, and that the thunderstorm will grow and last a very long time.

We can do the equivalent of retreating below tree line, and try to grow as many trees back as possible to reduce the risk; we could hunker down and hope the storm passes; or we could follow our original plan and keep going up. The option you choose depends on what you value; and if you value people's lives above arbitrary personal attainment, then the choice is obvious.

Above Tree Line

In the late 1990s, I was on a summer hike in the Rockies with a group of about a dozen people to a lake at an altitude of about 12,000 feet. As often happens on summer afternoons, a thunderstorm started to form. We were already at an abandoned mine about 800 feet below our destination when it became clear that the storm was coming toward us.

Any experienced hiker knows that the chances of being hit by lightning increase with elevation, and one of the most dangerous places to be is in an exposed area above tree line. It is also irresponsible to split up a group in such a situation. Half of the group defied both responsibility and safety, and chose to go up to the lake, while the rest of us waited for them at the mine, which had modest cover and was about 500 feet above tree line.

Less than a half-hour later, the storm moved in, just as we were joined by another group of hikers who were much less prepared than we were for both hiking and bad weather. Those of us with extra supplies helped out the newcomers, and showed them how to “hunker down,” making themselves a smaller target for the lightning. While waiting, we watched in horror as a lone climber on a nearby peak attempted to navigate along a ledge to get out of harm's way.

We debated whether to go back down the trail or stay at the mine. With so many people, there wasn't enough natural or artificial cover to keep us all from getting soaked and safe from the lightning. When the storm let up a little, we decided to make a dash toward the trees. The leader and a few others chose to wait at tree line while the newcomers and the rest of our group headed down the mountain.

Emergency vehicles were at the trailhead when we arrived, called by stranded hikers with a cell phone. We relayed our story, and waited for the rest of our group to arrive, which thankfully they did.

I recalled this story recently while working on my projections of world economic growth. Like hikers on a mountain, we are eagerly trying to get higher and higher.  Tree line represents the Earth's ecological carrying capacity, life's limit, beyond which we risk encountering lethal storms, such as those spawned by global climate change. We are currently above that point, and the storm is nearly on top of us. Some of us (climate change deniers) are in denial that the storm is dangerous, while others (business leaders and politicians) deny that we're even near the peak of a mountain, and like the hikers who split from the group are going higher regardless of the risk – perhaps even because of it. The trailhead is the safest place to be (the economy of a sustainable civilization), but it seems to be the last place anyone wants to stay.

We are already seeing casualties of the freaky weather we've gotten “closer” to. How many of us are smart enough to get below tree line and out of the rain before it's too late?