As the old saying goes “If it walks like a duck, quacks like a duck, looks like a duck, it must be a duck.”

And if it smells like a fossil fuel and is produced by the fossil fuel industry, then it probably is a fossil fuel.

So despite the best efforts by the oil industry for the best part of two decades to portray gas as a green fuel, it is still a fossil fuel.

It may be cleaner that oil but one thing it ain’t and that is green.

And so as the world enters what some are calling a “golden age of gas” this has serious consequences. The international energy watch-dog, the IEA has warned about the expansion of gas.

“While natural gas is the cleanest fossil fuel, it is still a fossil fuel,” said Nobuo Tanaka, chief executive of the IEA yesterday at a press conference in London.

He continued: “Its increased use could muscle out low-carbon fuels such as renewables and nuclear, particularly in the wake of the incident at Fukushima [the Japanese nuclear plant] … An expansion of gas alone is no panacea for climate change.”

Such is the global boom in gas, that the IEA is warning that the use of gas could rise by more than 50 per cent by 2035 from last year to overtake coal as the second-most used fuel, accounting for one-quarter of the world’s energy supply.

The danger of this is that this expansion could lead to a global temperature rise of 3.5°C, which in turn would lead to out of control warming.

So that is the madness of the situation – governments are promoting gas in the belief that it is cleaner than oil, but yet such is the increase of the fuel that it will lead to dangerous warming.

And also the dash for gas could be undermining investments in renewables, especially if the price of gas reduces.

Fatih Birol, chief economist of the IEA argues: “If gas prices come down, that would put a lot of pressure on governments to review their existing renewable energy support policies … We may see many renewable energy projects put on the shelf.”

And as we also know one of the drivers of the gas boom is shale gas produced by fracking. Whilst one of the well known dangers of fracking is the pollution of the water supply.

But what the industry is keeping secret is the dangers of leakage of methane, which could mean that the climatic impact is far, far greater greater.

Indeed a recent study by Cornell University found that generating electricity from shale gas produces at least as much carbon dioxide as coal-fired power, and perhaps more.

And if the shale gas boom continues for decades, we could all be sitting ducks ..