In a world of global warming green biotechnology can contribute in different ways to decrease carbondioxide emissions. I will shortly discuss two approaches:

- Create significant rises in the per hectare yield of crops to prevent further deforestation.

- Improve the potential of plants as a source for bio-energy, such as bio-ethanol or other types of fuel.

Today about 18% of carbondioxide emissions are the result of deforestation and decomposition of matter.  Our forests and tropical forests are the lungs of our world and for buffering the enormous carbondioxide emissions forests should be growing instead of decreasing. Part of the deforestation is the result of farmers turning (tropical) forests into arable land. In South America for instance Amazon rain forest is being turned into land for growing soybeans to feed our pigs and poultry. The growing world population, and especially the changing human diet – more wealth means eating not only more calories, but also consuming more animal protein – puts pressure on our food producing system. To save forests and also to save biodiversity we should be increasing the per hectare yield of our crops, and on the other hand seriously protect our forests and take initiatives to grow more forest. It’s not only about technology as farmers that turn forest into arable land are looking for a source of income. But from the technology side green biotechnology can seriously increase yields. There are now many examples of how tweaking the plants’ own genes can have serious effects on for instance the number of seeds, the size of seeds, the size of stalks, the amount of biomass and root mass. Certain modified rize varieties have shown more than 30% yield increase in field trials. Traditionally yields have been growing slowly at about 1-2% per year. So 30% or more yield increase is quite spectacular. Will the introduction of such new varieties take of the pressure to occupy more land for crops? It can, and I certainly hope so. But this may need policy to create the desired effect. Another intruiging question is whether it will be possible also to grow these crops using less inputs in the form of pesticides and artificial fertilizers. The less inputs we use the less energy – read carbondioxide emissions – we have to use to grow these crops. 

Plants are already used quite a bit for the production of different biofuels, such as biodiesel or bio-ethanol. Traditionally plants have been developed for providing healthy foods, and that is why corn nowadays have very big stalks, and wheat and rice are not very tall. Crops have not been seriously selected as a source of bio-energy. That means that there is still a lot of breeding potential to develop crops that have far better characteristics for bio-energy. One example that can be given is wood. Wood – or to be more precise: the cellulose and hemicellulose in wood – can be converted to bio-ethanol or other types of biofuel, but the conversion today is still inefficiënt. One technological strategy which also involves modern biotechnology is to develop better enzymes to do the conversion. A second strategy is to alter the wood properties to make it more suitable for the conversion. Poplar trees have been made that have less lignin. This is a sort of glue that is responsible for the enzymes not being able to do their work efficiently. Wood produced in a greenhouse has been shown to produce up till 50% more bio-ethanol than conventional wood. Also traditional breeding can help to improve performance, for instance by developing varieties that are better suited for growing in socalled ‘short rotation’. In short rotation you don’t want one dominant stem, but many equally good growing branches. Short rotation is a modern way of growing woody biomass and yields can go up to 30 tons of dry mass per hectare per year, depending on the circumstances.

 

The way green biotechnology can contribute to reducing carbondioxide emissions may seem somewhat indirect, but it is real and meaningful. Besides working on yield and the suitability for bio-energy there are other approaches, such as developing crops that can still grow and capture carbondioxide under harsh conditions such as drought, salinity or cold. At least one thing is certain: to fight climate change and become more sustainable we literally have to become greener. We have to grow as much plants as possible.