Calculating a carbon footprint and then matching those emissions to a carbon offset is a fiendishly difficult job. If you're in any doubt about that, just try out some of the wide number of free carbon footprint calculators on the internet and note how you'll probably get a different answer from each one.

So it's hardly surprising that there is move to quality going on with this service. And a listed company as big as Ecosecurities Group has a lot more to lose than a random consultant by getting it wrong.

They have just managed to land the advisory role on offsetting emissions from the Clinton Global Initiative Conference.

One of the banes of calculating offsets is to determine whether a particular offset - e.g. erecting a wind turbine, planting a tree, buying and inserting energy efficient light bulbs - would have happened anyway. The jargon is that it has to be proven to be "additional". And with carbon footprints, there are a great many variables - e.g. how do you drive your car, who is your power supplier and what fuel are they using at what time of the day? - that are all too often overlooked.

Footprints and offsets are far from a forensically accurate science. We can only see how this industry develops.