Biofuels and Biochar
Biofuels and biochar are among the many solutions proposed to mitigate climate but both have proven to be controversial.
Biofuels are alternatives to fossil fuels that are made from living things or their waste products.
They include solid biomass (such as wood or charcoal), biogas (such as methane produced from sewage) and liquids such as bioethanol and biodiesel.
The liquid biofuels are the most controversial because large areas of land are needed to produce them.
This means they can compete with food crops, raise food prices and promote deforestation, which itself releases significant amounts of the greenhouse gases that cause climate change.
Bioethanol is an alcohol fuel made by fermented the sugar in plants such as maize or sugar cane. Biodiesel combines conventional diesel with oils from plants such as jatropha seed, soybeans and oil palm.
At first glance liquid biofuels appear to be an ideal alternative to fossil fuels. They still produce emissions of greenhouse gases when they burn but the plants they are made from absorb carbon dioxide from the atmosphere while they grow.
But this benefit can be outweighed by the greenhouse gas emissions that occur in the production of these fuels.
Maize grown in the United States, for instance, depends heavily on fossil fuels – to produce fertilizers, power farm machinery, irrigate land and for transport.
It may be possible to overcome these problems with second- and third-generation biofuels (see Alternatives, below).
Another proposed way to use plants to help tackle climate change is through the use of biochar.
This involves using plants to absorb the greenhouse gas carbon dioxide as they grow. The plant matter can then be heated in a process called pyrolysis to produce a gas that can be used to generate power, and solid charcoal – or biochar – which can be buried.
When biochar is buried this effectively takes carbon out of the atmosphere and traps it underground for hundreds of even thousands of years.
An advantage of biochar over conventional biofuels is that it can be made using sewage or agricultural waste – such as the stalks of harvested crops.
An additional benefit is that biochar can improve soil productivity
Some nongovernmental organisations oppose biochar. They fear that its widespread use could promote land-grabs and deforestation, especially if biochar is included in the list of approaches for reducing greenhouse gas emissions Clean Development Mechanism
Critics of this view say that biochar would never operate on an industrial scale.
Concerns about biofuels (see above) have led to research into new alternatives, known as second- and third-generation biofuels.
The hope is that these alternatives could produce energy with significantly lower emissions of greenhouse gases, without competing with food production.
Second-generation biofuels use waste biomass, the stalks left behind after crops have been harvested or special non-food crops.
One technique involves converting the woody cellulose in such plant materials into sugars which are then turned into alcohol that can form the basis of fuel.
Such technologies are still at an early stage of development and scientists are exploring ways to use biotechnology to accelerate the process of fuel production.
Third-generation biofuels would use plants called algae, which can be grown in water, to capture carbon dioxide from the atmosphere. This carbon could then be converted into a biodegradable fuel.
Early experiments show that algae can produce much more energy than crops such as soybean grown on an equivalent area of land.
However, there are concerns that fuels made from algae would not have the right properties to replace conventional fossil fuels or other biofuels.
Research on third-generation biofuels is very new and major breakthroughs are not likely to happen soon.
Panos London has produced a briefing paper for journalists on the controversial topic of reporting on biofuels.
Journalists seeking the views of nongovernmental organisations that are critical of biofuels can turn to BiofuelWatch.
For a good overview of the global picture of biofuels and their likely costs and benefits, see the UN Environment Programme’s 2009 report Towards Sustainable Production and Use of Resources: Assessing Biofuels.
Biochar is far less controversial. A good source of news and views is the Re:Char website.
CASE STUDY – Unforeseen impacts of biofuels policies
The European Union thought it was doing the right thing in 2003 when it set a target of ensuring that, by 2010, biofuels would account for 5.75 percent of transport fuels used across its 27 nations.
Nongovernmental organisations and researchers were quick to warn that the target could promote perverse outcomes in poorer nations, such as an increase in deforestation to grow palm oil and soybeans, and less food for local populations there.
Clearing forests would also lead to a massive emissions of the greenhouse gases that cause climate change, and would hasten the decline of biodiversity, they warned.
An added concern was that large companies would seek to grab land from poor communities who had weak land rights so that they could use it to grow biofuel crops.
In November 2008, the European Union announced that it was reconsidering its target because of social and environmental concerns such as these.