I recently heard James Hansen (leading atmospheric scientist and climatologist at NASA) speak at UC Berkeley. He said it might make sense to support some biofuel production for jet fuel replacement as a transition fuel if grown on marginal (non-agricultural) land and not grown as monocultures. He differentiated this from growing biofuels for automobiles-which uses FAR more fuel.

Of course there are other considerations like WATER inputs in any plan to expand biofuels. Maude Barlow (international water advocate) said that California's current climate change plan (AB 32) contains plans to expand biofuels that is totally unsustainable from a water supply vantage point, as well as displacing food crops for biofuels,

I read of a similar development in India a couple of years ago. A professor from the Indian Institute of Science, Bangalore was visiting a poor village in a semi arid region of South India(where he did volunteer work).

During the course of conversations with the elders of the village, they talked about a useless wild plant (Jatropha) that grew under marginal soil conditions but the oil extracted from the berries was used them for lighting oil lamps.

He expanded on the idea and found that Jatropha Oil had a decent calorific value and could be used for running oil engines, found in most Indian villages, as a prime mover for irrigation pumps. Apparently this semi arid area has now been totally transformed with the avilability of water pumped from the aquifer.

Subsequently he even convinced the Indian Railways to test a mix of Diesel and Jatropha Oil on their diesel locomotives. The test was very successful and now IR has leased land along its extensive right-of-way to poor communities living around railway lines to grow Jatropha and sell the berries to the Railways for the production of oil, making it a WIN/WIN deal!!!

Kathy,
I think the bio fuels these planes are using are grown as weeds on the side of the road. Dont ussually water that unless there is a chance of brush fire. Its not like your compeeting with crop fields, I think. Algea is ussualy grown in vertical tanks and needs coarbon to grow.
Adam,
you know deep inside that Emirates’ green flight is a joke. You cant compair that to a normal flight. They didnt even count the fuel it took the other vehicles to pull it down the tarmac. Just emagine the damage air flight would cause on ice caps if more planes flew over the poles.

Using Jatropha curcas is progressing well in both India and Africa where cultivation on marginal land is developing reasonably smoothly.

It is not the only option, with the pongamia tree also under development.

These projects are more valid than use of soybean for biofuels. But much of the product in both Africa and India will replace mineral diesel at the local level with local oil presses and a local filter program. AND be used for local electricity generation or more importantly, water pumps and related simple but VERY important options for village and rural peoples eg fuel for small cultivation implements. They need this option.