An energy underclass could develop in Scotland if personal carbon trading is introduced in the fight against climate change, urban planning experts warned yesterday.

The Royal Institution of Chartered Surveyors in Scotland voiced concerns that low-income households could be driven into an eat-or-heat situation if tradable allowances were introduced.

UK Environment Secretary David Miliband signalled last year that the government was looking at the option of tradable personal carbon allowances as a way of curbing emissions.

People could then make money by selling surplus allowances.

However, the institution said: "The scheme could encourage vulnerable groups to compromise their energy use, and therefore their health and personal comfort, in order to sell-on surplus units to those who can afford to mitigate their energy use by buying extra allowance without making cuts."

The problem could be particularly acute in areas such as Glasgow, whose buildings have "some unique atmospheric and climatic issues leading to higher degrees of dampness penetration and condensation in buildings".

The Institute was launching a major report on measures needed to combat climate change over the next 40-50 years.

City Climate Challenge: your city, your responsibility compares current levels with UK targets to cut carbon emissions by 60% by 2050. The results give a dramatic insight into how our cities could look in the future.

Edinburgh would need 57,500 fewer cars on the road while Glasgow would need the equivalent of 1344 wind turbines, 35 Glendoe Hydro Schemes, nearly two nuclear power stations or 4.2 million solar panel roofs to meet the city's current demand.