13/05/2013 13:05 BST | Updated 10/07/2013 06:12 BST

400 PPM, We Know What We Have to Do

Yesterday, I wrote about the fact that CO2 levels in the atmosphere were about to hit 400 parts per million (PPM). This is significant because humans have never before endured this amount of greenhouse gasses in our atmosphere. The world we're building for ourselves is a dangerous one which we have no idea what it will look like even a decade ahead.

We've known for sometime that there was a strong possibility of this milestone being reached this year, and the news broke today from Mauna Loa Observatory in Hawaii; the 400 PPM milestone had been reached.

Despite the widespread knowledge that carbon is saturating our atmosphere, the human race is showing no signs in reducing our carbon emissions. Year on year, emissions increase as global climate talks stall.

Its clear what we need to do to avoid dangerous climate change; we must wean ourselves off fossil fuels, leave the remaining ones in the ground and make the big switch to renewable energy. Although the cleantech sector increases in size year on year, the amount of fossil fuel we extract each year surges too; this US administration has approved more oil drilling licenses per year that under the oil happy Bush administration.

The argument we most often hear from increasing exploitation of fossil fuels is to satisfy the energy hungry world we live in and developing countries should also have a chance to develop in the same way as the rich developed world has. But the true reality is that it's purely economics and politics. Fossil fuel companies are some of the most powerful companies in the world and they run government and thus policies.

The singular gift that the 400 PPM statistic gives us is the fact that its a nice round number - a scary number which represents scary facts and an inhabitable planet if we don't get our act together. Together these warnings must spur action. It's now up to the world's big economies in the EU, USA, China, India, Russia and Brazil to make radical, bold and urgent policy changes which transforms us from fossil fuel economies to green economies. 400 PPM tells us we can't wait any longer.

This has been cross posted with A greener life, a greener world.