The amount of water needed to produce each liter of bio-fuel is yet another, often-overlooked cost, and the amount of water needed can vary several hundred-fold, depending on the type of crop being produced. In this oversimplified carbon-dioxide-neutral cycle, the amount of energy consumed – mostly from oil and coal – for fertilizers and other crop-production materials is, in most cases, ignored. In an effort to mitigate climate change, bio-fuels have been developed under the premise that carbon-dioxide emissions are offset by crop growth. The case of food-derived bio-fuels is one example that demonstrates how interdependent these four elements of modern chemistry are. Although none of these are proper chemical elements, these modern versions of the classical elements are the essential components of any solution to today´s great challenges. This view returns us to a new four-item list - the four elements of modern chemistry: food, energy, water and climate. But, when it comes to enacting innovative policies to improve life worldwide, I argue that we can return to taking a more simplified view. Today, life is exponentially more complicated, with the list of elements numbering well over 100. It was simple for 2000 years - controlled by only four elements: Earth, fire, water and air.
![4 elements essential to life 4 elements essential to life](https://www.researchgate.net/publication/289534863/figure/fig1/AS:614156629712897@1523437759844/A-biological-periodic-system-of-the-elements-PSE-indicating-the-essential-elements-The.png)
Javier Garcia Martinez is director of the Laboratory of Molecular Nanotechnology at the University of Alicante, Spain, founder of Rive Technology and author of The Chemical Element: Chemistry´s Contribution to Our Global Future. By Javier Garcia Martinez November 25, 2011