FIFTY, and ten, are two quite normal numbers but they are likely to pose a significant problem for the government. Despite Treasury opposition parliament has recently ratified the UK's fourth carbon budget, and so set itself, and us, a daunting challenge.

Quite simply they have confirmed the ambition to reduce the CO2 we produce, and the target is to halve it, produce fifty per cent less than in 1990, and this between 2024 and 2027. That's just over ten years away, and while it's technically possible we won't manage it if our past record is anything to go by.

We should also remember that the national figures don't include emissions from flying or shipping, both of which are growing strongly. Similarly they ignore emissions from manufactured goods that we are responsible for, but are produced in other countries, up to a third again on top of the individual nine tonnes a year that is our personal contribution.

The starting point is the 1990 total, that is 592 million tonnes, which will need to be 296 million within ten years or so, and our record is patchy. It only fell by 10 percent in the 18 years to 2008, to 531 million tonnes, but by 2012 it was down to 479 million tonnes because of the economic recession, that is a fall of 21 percent in 22 years.

Continuing at even that rate means we will still miss the fourth carbon budget target, particularly as there has been a measure of economic recovery that's likely to strengthen, so producing more CO2. We were lucky that we could replace coal with North Sea gas after the pit closures, but now more cars, roads, houses, additional airports, high speed rail, replacement power stations, and fugitive leaks from fracking wells all mean more CO2, not less.

There's not enough time to build new nuclear power stations so we'll need to use less energy, and that means decisions that all governments have ducked up till now. The unambitious, and misguided, market approach to the insulation of houses, the Green Deal, has failed, and it now needs a robust approach, more than the promise of Smart Meters, something like the action taken in British Columbia.

CO2 emissions there are being driven down through carbon taxes. The best and fairest approach seems to be that all the fossil fuels, coal, oil and gas, are taxed to reduce consumption, and the reason it works is that the tax is used to balance the lowest income and corporation tax in the whole of Canada. Those using less carbon rich fuel will benefit and the extravagant will be out of pocket.

The polluter pays principle is alive and well.