When we set up Sandbag in 2008 we chose the name 'Sandbag' for a simple reason.

To make a link between one of the likely impacts of climate change: increased flooding (thanks to changes in rainfall patterns and increased sea level) and the need for action. Sandbags provide emergency protection in the here-and-now, but we, as an organisation, wanted to give individuals the chance to use a form of protection from future flooding and climate change.

Our idea was to buy up the legal permits or 'allowances' that were put in place to limit companies' ability to emit greenhouse gases. Since 2008, under EU-wide laws, all big emitters like power stations were required to submit sufficient allowances to cover their emissions. By buying some and taking them out of the market, we realised we could reduce the total allowable amount of pollution.

Thanks to Flickr user LordOtter for this Somerset floods watercolour

That was 2008, when we thought the laws that set up this system were fit for purpose.

Once we looked under the hood in more detail, it quickly became apparent that the legal cap that had been set, dictating the number of allowances created, was too generous. This meant there were millions of spare allowances sloshing around. With the onset of the recession, what was a stream of spare allowances rapidly became a deluge.

Currently it's estimated there are around 2 billion allowances too many – roughly 4 years worth of the UK's total annual greenhouse gas emissions. With so much over-supply, their value is reduced, which means they are very cheap to buy. And so, instead of stimulating investment in low carbon solutions, we've seen the EU's cap on emissions allow for a reversal of fortune for coal – the most polluting form of fossil fuel.

Thanks to Flickr user Neil Howard (neilalderney123) for this photo of floods in Winchester

The need for a radical reform of the policy is obvious and urgent. We continue to offer people the option to buy and destroy pollution, but we are also much more focused on lobbying to achieve that through changes to the law.

We do this by highlighting just how broken the system is in regular reports, via our online maps, and in events and lobbying meetings in the UK and the rest of Europe. We're far from alone in wanting a fix – lots of more efficient and cleaner companies would also benefit from a higher price being applied to pollution. But sadly a host of vested interests profit from the status quo, who lobby to keep things just as they are.

Thanks to Flickr user Phil John for this photo of floods at Egham

And so here we are in 2014 with some of the worst flooding and heaviest rainfall in the UK for hundreds of years. It's an example of the kind of extreme weather event that climate scientists have been warning us about.

Sandbag might not be able to hold back these floods, but we can offer virtual 'sandbags' – cancelled pollution permits, which prevent CO2 being released, and so act to prevent climate change and even worse flooding in future.* And alongside it, we send a message to our policy makers to fix the climate now.

We can't afford to wait until the next decade to put a proper limit and price on climate-changing pollution. The effects are already being felt here and worldwide and will continue to get worse. It is time to act.

For more information please visit: www.sandbag.org.uk

Thanks to Flickr user Gareth Thompson (EVO GT) for this photo of Porthcawl at sunrise

*NB: Sandbag doesn't make any profit from the sale and destruction of these permits.