High in the mountains of nations like Mexico and Costa Rica, huge cloud banks blanket vast stretches of forest. Mosses and ferns, frog and toads, Monarch butterflies and rare birds thrive in these cool, wet areas. Cloud forests are rare: They make up less than 3 percent of all tropical forests [PDF]. They’re also particularly vulnerable to climate change, which means they may all but disappear during this century.
In Mexico, rising temperatures could eliminate 68 percent of the country’s cloud forest by 2080, according to a new study in Nature Climate Change. Warmer temperatures mean that clouds start forming higher up. The stretches of mountain where cloud forests develop start drying out, and the species that have adapted to live there begin to die off or migrate. The plants that live in the forests tend to grow slowly, too, and spread their seeds only a short distance, so it’s unlikely they’ll be able to migrate to new cloud-covered stretches, if those even exist.
And warming temperatures aren't the only hazard cloud forests face. Loggers cut down portions for timber, and farmers for agricultural land. Mexico protects a portion of its cloud forests from these dangers, but the study found that the areas protected from being cut down are among the most vulnerable to climate change risks: More than 90 percent of the protected areas won’t be able to support cloud forests a few decades from now. That leaves the unprotected areas, which are threatened by both climate change and deforestation. If left unprotected, the study’s authors predict, 99 percent of Mexico’s cloud forests will be gone. In Costa Rica, climate change could destroy two-thirds of the country’s cloud forests.
Despite Rick Santorum's insistence otherwise, carbon dioxide can wipe out entire populations of trees. The case of the disappearing cloud forests cuts a little deeper than the loss of forests of aspens and pine, though. Cloud forests are the type of rare places that we dream of visiting, the type of places we get on planes just to visit and think about for years after we get back.
But in Mexico, losing cloud forests won’t only affect tourists or the bounty of plant and animal species, the names and shapes of which most of us will never learn. Many cloud forests grow in regions with long dry periods, and they have the special ability to collect water when none falls. When the clouds and fogs pass through the forests, water condenses and can be harvested. In Mexico, that harvest helps provide water for Mexico City.
There's no easy solution—saving cloud forests requires slowing climate change. The study reminds us of one of the major threats posed by warming temperatures: Some of the most magical places on earth could very well go away, forever.