by Matthew Knight (CNN)  It wasn’t so long ago that biofuels were being heralded as the savior of the planet and a thoroughly green solution to our climate woes. But fair winds have been replaced by persistent storms of criticism. But is it justified? Principal Voices has spoken to three people — an economist, a scientist and an environmental campaigner — at the heart of the biofuels debate. Here, they have their say on biofuels. Have yours at bottom of the page.

The Economist

Keith Wiebe is the service chief in the Economic and Social Development Department at the Food and Agriculture Organization of the United Nations (FAO).

…The background is that you’ve had the gradually increasing income and demand for more, and different types of food in emerging economies. You’ve had a gradual decline in international stocks of food, you’ve got higher oil prices which means the costs of production are going up. There have been some been some production setbacks in a couple of key export countries such as Australia and also a rapid increase in demand for maize and vegetable oils for biodiesel and ethanol production.

All these factors interact and lead to policy responses from countries to limit exports of commodities to protect their domestic consumers. It’s impossible to disentangle a specific portion or to attribute a particular portion to the price increases.

One thing to keep in mind is that biofuels play a role in the current high prices but they are certainly not the only factor. The other thing is that they have adverse short term impact on food prices. They have an adverse impact on poor consumers particularly in developing countries. But there is an opportunity over the longer term at least for small farmers who do have access to resources to adjust their production patterns. And high prices give them an incentive to do exactly that.

…The Scientist

Dr Richard Pike is the chief executive of the Royal Society of Chemistry.

…Biofuels will clearly have an application at a local level. I think there is a general view that at a very local level — and I’m talking of small townships that are surrounded by land that could cultivate biofuels — that it is probably sustainable.

Whether it can be applied on a large scale in a sustainable way will vary tremendously from country to country.

…The Environmental Campaigner

Deepak Rughani is co-director of Biofuelwatch, a campaign group backing the expanding call for a moratorium on agrofuels* in the European Union.

…Unfortunately, switching to rapeseed oil, even if it was affordable, would not necessarily help matters: As confirmed by a UN report, Europe’s use of rapeseed oil for bioenergy is one of the main reasons for rising palm oil prices linked to shortages in the food and cosmetics markets. Inevitably rising prices make deforestation and peat drainage in South East Asia much more profitable.  READ MORE