If Borneo’s forests are cleared for oil palm plantations then the endangered orangutan may become the first great ape to go extinct at the hands of humans.

But since protecting tropical forests also prevents climate-warming gases like carbon-dioxide from entering the atmosphere, some conservationists think intact forests should be worth something to rich nations needing carbon credits.  How much they are worth exactly and whether a carbon market can really stave off extinctions has been a matter of debate among scientists and policy-makers.

Now, an analysis coming out this week in the journal Conservation Letters suggests that even a voluntary carbon market can go a long way towards saving the orangutan, pygmy elephant, and 38 other globally threatened mammal species in Indonesian Borneo (Kalimantan).

“126 billion tons are traded on the carbon market,” says lead author Oscar Venter of the University of Queensland in Australia, “and it would be great if a small amount of that can be siphoned off to slow tropical deforestation.”

In the current study, Venter joined forces with conservationists to map out, permit by permit, 3.3 million hectares of proposed palm plantations that overlap native forest in Kalimantan.  They compared the potential profits from the initial timber harvest and palm oil development to the amount of carbon stored in standing forests and peat biomass to find out how different areas would fare on a carbon market like the Chicago Climate Exchange. 

To prevent deforestation throughout the region, Venter says that forest offsets would have to sell between $10 and $33 per ton of carbon in order to compete with palm plantations.  However, if the market focused only on peat-rich areas, then the price of carbon would only have to be half that price.  And, as it turns out, those same peat areas contain twice the number of threatened mammals per acre than less carbon-rich forests.  In addition, 29 percent of planned plantations that harbor orangutans or elephants, store more carbon per acre than plantations lacking those species.

Rhett Butler, founder of Mongabay.com and the environmental analyst who voiced concerns about the carbon market’s effectiveness in Conservation Letters earlier this year, agrees with the new study. He says that the inclusion of peat biomass in the carbon market makes fighting global warming—and preserving biodiversity—competitive with palm oil.

“That makes a tremendous difference,” Butler says, “because you can double the carbon value.”

Image of wild orangutan in Kalimantan courtesy NeilsPhotography via Flickr