A hardy little plant that was once briefly heralded for its potential to alleviate climate change is getting another 15 minutes of fame. The Jatropha curcas is a strange species of flora. It's leafy and green; sometimes it takes the form of a shrub, but it can also become a tree up to 20 feet (six meters) tall. It came from the tropics of Central America and can thrive in semi-arid climates with low-nutrient soil. Jatropha plants bear a poisonous little yellow-green fruit; inside each are several black seeds. If you crush them, you get oil. 

A study recently published in the international science journal Earth System Dynamics found that Jatropha plants have great environmental potential; their leaves absorb high amounts of carbon dioxide, which could help to slow the disastrous effects of climate change in some of the world's most vulnerable regions. The concept is called "carbon farming."

The researchers tested Jatropha's capabilities in plantations in Egypt and Israel. Their report claims that over a 20-year period, a single hectare of Jatropha plants could capture between 17 and 25 metric tons of carbon dioxide annually. Lead study author Klaus Becker told SciDev.Net that plants can increase rainfall and lower desert temperatures by 1.1 degrees Celsius, or about 2 degrees Fahrenheit -- quite a significant drop, especially in drought- or famine-prone regions.

Jatropha plants would work best in dry coastal areas, which seaside desalination devices could irrigate. The end costs involved would be between $56 and $84 per ton of carbon dioxide captured, according to scientists' estimates, which makes Jatropha carbon farming a viable alternative to more high-tech methods of carbon capturing.

But not everyone is convinced of Jatropha's potential. The plant has already been touted as the next best thing once before, not because of its carbon-farming potential but because of its oil. But in that instance, researchers' grand ambitions fell flat.

The oil found in Jatropha seeds is ideal for biofuel. Around 2006 and 2007, environmentalists and investors were excited about this potential -- especially considering how hardy and adaptable Jatropha plants are. They reasoned that plants could be cultivated on unused land, thereby producing green fuels without encroaching on existing agricultural plots or forests.

That wasn't the case, however. Jatropha can indeed thrive in unforgiving environments -- but its fruits and seeds simply aren't productive where the soil is poor. To produce enough oil to be economically viable, Jatropha plants did require arable land and would have to compete with crops and forests. Major corporations such as BP PLC (NYSE:BP) felt the burn. The London-based company set out on a $160 million joint venture with a company called D1 Oils in 2007 but ditched the project in 2009 -- after planting 200,000 hectares -- to focus on other alternative options like ethanol and biobutanol. Many small-scale farmers in developing countries also bought into the dream of the perfect plant, only to end up with less productivity than they had bargained for.

Researchers remain optimistic about Jatropha's carbon-absorbing potential, and testing will continue. "The results are overwhelming," study author Becker told the BBC. "There was good growth, a good response from these plants. I feel there will be no problem trying it on a much larger scale, for example ten thousand hectares in the beginning."