Green Aviation

The airline industry is seen by many as one of the main culprits when it comes to carbon and greenhouse gas emissions -- and therefore climate change.

It has been heavily criticised by environmentalists for perceived inaction over its high CO2 output -- estimated at between two and 10 percent, depending on whose figures you want to trust.

However, with oil prices doubling worldwide in the last year the incentive for the aviation industry to reduce its fuel output is now as much driven by hard economic realities as environmental factors.

Although there have been efforts to mitigate the impact of air travel through initiatives like carbon offsetting, many see this as a short-term solution and as such of limited value.

The search is on to find ways of reducing planes reliance on fossil fuels and according to the CEO of Lufthansa, Wolfgang Mayrhuber there is only one area that will provide the answer in the long run: "technology, technology and again technology."

The biofuel option

Within the airline industry itself many are putting their faith in biofuel as a viable alternative to petroleum fuels. So-called first generation biofuel is made from organic materials -- often food crops -- that are broken down to produce oil or alcohol fuel like ethanol.

Its chief champion so far is the owner of Virgin Atlantic, the tycoon Richard Branson, who has pledged to invest profits from his transport empire in to biofuel production.

The use of biofuel remains contentious, however, with claims that harvesting of the crops needed to make the fuel robs locals in the developing world of valuable farmland thereby pushing up food prices. Environmentalists also argue that it often leads to deforestation, making any CO2 savings largely redundant.

Mindful of these criticisms, Branson used a mix of coconut oil harvested from existing plantations and oil from palms that grow wild to fuel a flight from London to Amsterdam earlier this year. The Virgin Atlantic 747 that left Heathrow in February was the first commercial aircraft to be powered partly by biofuel.

ven so the plane still relied on 80 percent conventional jet fuel, and many are skeptical whether first generation biofuel has enough energy density to work on its own. The harmful impact on food prices and the sheer volume of crops needed in their production has led many airlines to set their sights on second and even third generation biofuels that come from non-food crops.

Air New Zealand, for example, has begun testing Jatropha, a bush native to Central America that can grow in very arid environments, requires little water and has a much higher yield than crops like corn.

Rob Fyfe, CEO of the New Zealand national carrier said they decided on the crop "because we wanted a fuel that had no connotations in terms of competing with the crops from indigenous forests." Air New Zealand has committed to running its fleet on 10 percent non-food biofuels by 2013.

Going green with algae

Other airlines are looking away from the land for the solution. Boeing has joined energy giants such as Chevron Corp. and Royal Dutch Shell in supporting research in to the use of algae.

Researchers have already managed to extract vegetable oil from algae harvested on ponds. It is still only at its early stages but scientists believe algae could potentially produce much higher yields than other biofuel with the added advantage that it would not take up valuable farmland.

Two members of staff from Boeing sit on the board of directors of the Algal Biomass Organization, a U.S. trade body set up to accelerate research and funding into its use as an aviation fuel.

Inspired by birds

Creating efficiencies is not just about improving fuel, of course. Airlines are also looking at aircraft design and the way the skies are managed in the hunt for savings.

Mayrhuber told CNN he would like to see the rules governing the flight paths planes are allowed to travel along relaxed to allow aircraft to choose the most energy efficient routes.

"From Europe we have three entry points into China," he says. "If you asked the birds that migrate, they take a different route every day. Why? It isn't so they don't pay the fuel at the station. It is energy. They take the best route every day and we believe that there are airways that are outdated."

According to Mayrhuber, if planes were allowed to travel unrestricted across Europe it would reduce carbon emissions from aviation on the continent by 12 percent overnight.

It is not only the migratory routes of birds that aviation experts are looking at. They are hoping that examining the design of nature's ultimate flying machines might turn up some unexpected solutions. USA Today, for instance reported that scientists are investigating how it is that birds can fly without the large vertical tail fin required on planes. If they could solve this conundrum, getting rid of the fin would very likely lead to fuel savings.

Many of these technological changes are unlikely to happen in the near future (if they happen at all) while environmentalists insist climate change is of pressing concern right now. The jury is still out on just how seriously the aviation industry is taking the threat of global warming, but with oil prices still on the up it may be forced to act sooner rather than later.