Sterner who presented a workshop at the University of Cape Town this week has been advocating the use of taxes on fuel to force consumers and companies to use less petrol and fossil fuels to slow if not stop the warming of the earth's atmosphere.

"International research predicts that the earth's average temperature will rise by two degrees Celsius over the next 50 years. However, this will not be uniform as in some areas it will rise by between five degrees and 10 degrees," he said.

Sterner said that in some of these hotter areas such as India, which are already heavily populated, such a rise would lead to water and food shortages and then to increased social strife.

He believes that the world economy is still heavily dependent on the use of fossil fuels and this will not lessen in the coming half centaury.

"Underground coal reserves are still huge and there are still very large untapped oil and gas reserves. I don't see the dependence getting any less despite what the 'peak oil' school of thought says," Sterner said.

The SA government's Integrated Resources Plan that aims to double the country's generation of electricity over the next 20 years was still heavily dependent on coal-fired stations with Eskom to bring into commission three such plants in the next two years.

But for Sterner the more immediate global problem was that of the use of petrol for transport.

"The oil lobby has long argued that increased taxes, especially on petrol, would be detrimental to the poor. So I decided to take a look at that and work out if it is true. And it is not," he said.

Sterner argues that, apart from the US, the poor in most countries cannot afford to own their own vehicles and so depend on public transport.

He has compiled a book of research done by associates around the world. The book is titled "Fuel Taxes and the Poor: The Distributional Effects of Gasoline Taxation and Their Implications for Climate Policy."

"Apart from the US, in most countries the poor cannot afford to own their own vehicles. So they are either heavily dependent on public transport or they walk. However fuel prices make up a very small portion of their financial burden compared to the rich," he said.

Sterner also argues that subsidies should never have been placed on fuel, where in most third world countries they only make up a third of public transport costs, but should rather have been used to help with the operational costs of those public utilities.

Referring to the recent Nigerian protests following that country's government decision to stop fuel subsidies, Sterner said that those protests were being led by people who had been making money out of the system.

"The Nigerian subsidies created a large arbitrage opportunity for people to sell petrol illegally to neighbouring countries. Now it has been stopped because that system was unsustainable as the Nigerian treasury has run out of money," he said.

The failure of the COP17 climate change talks held late last year in Durban did not surprise Sterner, because he said he held no high expectations for them.

"We will only get a lasting agreement on carbon emissions once the US and China come to an agreement. And when they do, we may very well see that they pass some resolution that makes the use of fossil fuels a crime against humanity and then they will say: 'use those fuels and we will come and get you'," he said.

SA has one of the highest rates of fossil fuel use in the world largely because of the use of coal to generate electricity and to produce petrol.

"Yes, this country certainly has a problem," Sterner said.