Collectively, the Dundee Energy Recycling Limited waste-to-energy incinerator at Baldovie, the nearby Michelin tyre plant and the Nynas bitumen refinery at Dundee Harbour were responsible for releasing 122,000 tonnes of the gas in 2008.

With the average car releasing more than 250 grams of carbon dioxide per mile and travelling around 9000 miles per annum, according to UK Government figures, the gas released by DERL, Michelin and Nynas works out as equivalent to the emissions from 53,000 motors over the span of a year.

Transport Scotland figures show that fewer than 50,500 cars were on Dundee’s roads last year.

The total carbon given off by the three plants is equivalent to more than 476 million car-miles — or driving around the equator more than 19,000 times — and weighs the same as 13,000 African bull elephants.

The DERL incinerator was by far the biggest producer at around 73,000 tonnes, with Michelin producing 25,000 tonnes and Nynas 24,000. While Michelin and Nynas’ carbon dioxide emissions have decreased in each of the last four years, DERL’s total has varied from 83,700 tonnes in 2005 to 68,000 in 2006 and 85,500 in 2007, before dropping again to current levels.

Duncan McLaren, chief executive of Friends of the Earth Scotland, said the release of the SEPA figures earlier this month allowed close examination of “those big plants that put out big emissions”.

He was particularly critical of DERL — which he regards as highly inefficient — but also called on businesses to take a responsible attitude towards the by-products of their operations.

“The trouble with so-called waste-to-energy is the efficiency of the process,” Mr McLaren said. “Going on published information, the DERL plant doesn’t capture any of its waste heat. At its maximum capacity DERL can produce 34 megawatts, but is only running at about 25 per cent efficiency.

“The only thing to do which would reduce emissions at DERL is to make the plant more efficient. If we’re going to go down the route of incineration then it has to be combined heat and power, which is two-and-a-half times more efficient.”

Such a move would see the plant capture the heat it releases and use it to generate hot water. While that wouldn’t reduce the level of carbon dioxide released, it would make the site much more productive for the same level of carbon dioxide emissions.

But he also stressed that a greater public effort to reduce waste and increase recycling would result in far less waste for local authorities to “deal with”.

“The first thing we need to do is waste reduction,” he said. “The least damaging form of waste is that which you don’t have. After that, you recycle as much as you can.

“The Scottish Government wants to see 70% recycling by 2020, but, at current rates, we’re not at that level and have got some way to go. Then, if you have residual waste that still has calorific value, then you want to recover that useful energy in the most efficient way you can.”

Mr McLaren also called for Michelin and Nynas to make “efficiencies” in their processes, predicting that the European Union’s emissions trading scheme would increasingly incentivise a responsible approach by industry.

Carbon’s “price per tonne” is expected to increase over the duration of the EU-wide quota system, making saving carbon attractive to companies who can then sell on their unused allowance at a profit.

Climate change and global warming, which scientists believe is largely caused by the increasing amount of so-called greenhouse gases in the atmosphere, is predicted to cause changes to weather patterns, the melting of the Earth’s ice caps at the north and south poles and the extinction of animal species.

Most nations of the world — with the notable exception of the USA — have signed the Kyoto Protocol, an international agreement which aims to reduce greenhouse gas emissions. It’s hoped that an updated agreement can be reached at a UN Climate Change summit in Copenhagen in December.

The UK Government recently launched a £6 million “Act on CO2” primetime television advertising campaign, which is designed to show the public that making small differences to the way we all live our lives could help cut Britain’s total carbon emissions by more than 40%.