One ofÂ myÂ most memorableÂ trips was an adventure excursion to Costa Rica some years ago. In addition to the adventure, the beautiful landscapes, the ocean, and the active volcanoes, I was impressed with the amount of life the country boastsÂ in relation to its size.Â Costa RicaÂ constitutesÂ only about 0.1% of the world’s landmass, but itÂ is home toÂ a fullÂ 5% of the world’sÂ species.
That’s the rain forest for you. It’s teeming with life.
Unfortunately, climate changeÂ may beÂ having an adverse effect on that life as we speak.
Now, of course, we’ve all heardÂ that the most significant harm from climate change so far has been in the polar regions. Melting ice and depletion of food sourcesÂ at the poles are stories thatÂ have regularly been in the news. But it seemsÂ tropical plants and animals may face an even greater threat.
Scientists, led by Robert K. Colwell of the University of Connecticut, sayÂ some tropical species are living near their maximum temperatures already, and warmer conditions could cause them to decline.
Colwell and his team studied conditions in Costa Rica, and found that, where many speciesÂ with range problems caused by climate changeÂ can shift range locations relatively easily, thereby countering the effects of warming in their natural habitats, tropical speciesÂ face a more daunting prospect,Â becauseÂ regions that can support themÂ are too far away for them to make a shift. They simply cannot get to where they can survive.
Publishing their findings in an article (free abstract only) in last Friday’s edition of the journal Science, the teamÂ believesÂ some tropical speciesÂ affected by climate change will instead move to higher ground where temperatures are cooler. They cannot moveÂ north or southÂ to aÂ suitable climate, so they are forced to move up, into theÂ surrounding hills and mountains.
Of course those species that already live in the hills and mountains have no place to go, and the influx of lowland speciesÂ could have an adverse effect on them as well. That isÂ if rising temperatures don’t cause them to die off first.
Jens-Christian Svenning of the University of Aarhus, Denmark, and Richard Condit of the Smithsonian Tropical Research Institute, who were not part of the research team,Â agree thatÂ “[the] numbers suggest large risks.” But they point out that Colwell’s findings are likely to be controversial, because thereÂ are stillÂ large gaps in the knowledge of species’ sensitivity to climate change.
Meanwhile, a separate paper in the same journal reports that warming climate has already scrambled the ranges of small mammals in Yosemite National Park.
At any rate, thisÂ particular effect of climate changeÂ is very possibly transpiring right now, and shines an everÂ brighter light on what we stand to lose if we don’t take action. The government of Costa Rica at least appears aware of the problem and seems willing to do its part. In 2007, it stated thatÂ it wantsÂ to be the first country to become carbon neutral by 2021.
We’ll see if they can do it, and if others will follow.