Climate change debates sometimes feels like reading a bowl alphabet soup: IPCC, UNFCC, CCS, PPM and so many more acronyms it can get just plain silly.

The diversity of acronyms is matched only by the plethora of ways to express action on climate change: 40% on 1990 levels by 2020, 50% aggregate equivalent gases on 2000 levels by 2030, 100% renewable by 2017.

It was this maze of numbers and acronyms that led US climate campaigners to start 350.org, an organisation calling for CO2 levels in the atmosphere to stay at or below 350 parts per million, which is widely agreed as the level needed to prevent dangerous climate change.

The idea of 350 is a great one, a simple number that can easily be used as a yardstick for success and failure of climate policy. Will the agreement/policy/legislation keep carbon to 350 or below? Yes? Good. No? Bad.

Of course there are organisations that are calling for higher and lower numbers, different measure and a diversity of ways of expressing these. This is part of the strength in diversity of environmental campaigners, but for lay people it can all be a little bit much to take in.

The effect of the 350.org campaign in the States, where the population’s understanding of climate issues has traditionally been below Australian and European, has been profound. One number, easy to understand and explain and talk about has acted as a rallying point for countless activists, organisations and individuals across the country.

Now those three little digits are having their moment on the international stage. October 24th will be a massive day, with people from across the globe calling for 350 to be agreed upon as the maximum level of pollution allowed.

Groups around Australia and the world are planning for a huge number of creative, fun, inspirational activities all about that magic number 350. There are boats and picnics, human signs and concerts, videos and dances. To find what is happening in your community go to: www.350.org

In December world leaders will meet in Copenhagen to decide upon an new protocol for tackling climate change, the last of these was twelve years ago, in Kyoto. For people wanting to know if the meetings have gone far enough, 350 is one way to measure these without getting overwhelmed by the alphabet of acronyms and googleplex of numbers out there.