Last week the average concentration of carbon dioxide in the atmosphere [reached 400 parts per million](http://www.bbc.co.uk/news/science-environment-22486153), a level which is said to be unprecedented in human history.
Leading scientists and policy makers say that we should be aiming for no more than [350 parts per million](http://en.wikipedia.org/wiki/Climate_change_mitigation_scenarios#350_ppm) to avoid catastrophic runaway climate change.
But what’s in a number? Why is the increase from 399 to 400 significant?
While the actual change is mainly symbolic (and [some commentators have questioned](http://www.latimes.com/news/science/sciencenow/la-sci-sn-carbon-dioxide-400-20130513,0,7196126.story) whether we’re hovering above or just below 400), the real story is that we are badly failing to cut emissions fast enough.
Given the importance of this number, which represents humanity’s progress towards tackling one of the biggest challenges we currently face – the fact that it has been making the news around the world is very welcome indeed.
Why don’t we hear about the levels of carbon dioxide in the atmosphere from politicians or the press more often? While there are regularly headlines about inflation, interest and unemployment, numbers about carbon emissions rarely receive the level of attention that they deserve.
We want this to change. And we think that having more timely and more detailed information about carbon emissions is essential if we are to keep up pressure on the world’s governments and companies to make the cuts that the world needs.
As our [Advisory Board](http://okfn.org/about/advisory-board/#Professor_Hans_Rosling) member [Hans Rosling](http://en.wikipedia.org/wiki/Hans_Rosling) puts it, [carbon emissions should be on the world’s dashboard](http://blog.okfn.org/2013/01/21/carbon-dioxide-data-is-not-on-the-worlds-dashboard-says-hans-rosling/).
Over the coming months we are going to be planning and undertaking activities to advocate for the release of more timely and granular carbon emissions data. We are also going to be working with our global network to catalyse projects which use it to communicate the state of the world’s carbon emissions to the public.
**If you’d like to join us, you can follow [#OpenCO2](https://twitter.com/search?q=%23OpenCo2&src=typd) on Twitter or sign up to our [open-sustainability](http://sustainability.okfn.org/) mailing list:**
*Image credit: [Match smoke](http://www.flickr.com/photos/amagill/176876227/) by AMagill on Flickr. Released under Creative Commons Attribution license.*