Phys.org: Biofuel breakthroughs bring 'negative emissions' a step closer
"We must aim for "negative emissions". This means removing carbon dioxide from the atmosphere, and ideally returning to pre-industrial atmospheric CO₂ levels. This is a daunting task: the present atmospheric concentration is 410 parts per million (ppm), compared with around 280ppm before the Industrial Revolution. Intriguingly, recent breakthroughs (see below) in biofuel research have brought this prospect a step closer. To understand why, we must first know a little about biofuel production."