Following Brazil's example, other countries which used a lot of fossil fuels decided that they too would join the biofuel revolution. Biofuels are, in principle, carbon neutral so growing plants to make fuels sounds like a great idea. Sadly, it isn't. There are big problems:

What is 'carbon neutral'?
When a tree or plant grows, it sucks in carbon dioxide from the air and makes it into other carbon compounds like wood or sugars. If people later then burn these, or make them into biofuels, the same amount of carbon goes back into the air. So this cycle or growth followed by burning is not adding more carbon to the air than was taken out in the first place by the tree. So it's called 'carbon neutral'. Fossil fuels like oil and coal add more carbon to the atmosphere every time they are used so they are not carbon neutral.

1. to grow enough plants to fuel all the world's cars, ships, planes and power stations would need more land than there already is!
2. many biofuels, like ethanol, are made from plants which used to be grown for food only. This means there's a serious conflict of interests: is it more important to feed people or to make fuels? Hundreds of millions of people around the world are already nearly starving and climate change is going to make things much worse. The world's population is now well over 7 billion people, growing all the time, so more farmland will be needed to grow more food
3. tropical rainforests are being destroyed on a massive scale to be replaced with palm oil plantations. This destruction releases vast amounts of greenhouse gas (mostly CO₂) which is exactly what the palm oil plantations are supposed to be stopping. Worse: the plantations destroy forests which once teemed with all kinds of living things. Because their habitat is cut and burned, the plants and animals - orang utans in Indonesia are the best known animals - die or become extinct
   Oil from the fruits of these palms has long been used in foods but now it is being used on a much larger scale to make a biofuel called biodiesel.
4. growing some food crops to convert into fuel is very inefficient, using almost as much energy overall (from fossil fuels burned in machines to farm and process them, for example) as is actually produced