A new "carbon map" of the UK has revealed London as the worst offender for emitting CO2, with Aberystwyth among the most fuel-efficient towns.
Small measures, such as cycling, cut carbon, says the trust
The map, released by the Carbon Trust, details tonnes of carbon dioxide emitted per square kilometre per year, and emissions per head of population.
London produces 9.46 million tonnes (1.09 per head) annually, while Ipswich and Aberystwyth emit 0.42 per head.
The trust said the worst polluters were often businesses.
Based on 2003 data, the study estimated the amount of carbon produced by offices, factories, power stations, vehicles and homes.
In London, it found 30% of carbon emissions were down to business, while in Sheffield the figure was 44%.
The trust called on people to carry out measures such as turning off lights when they are not needed.
This can cut lighting bills by up to 15% and also benefits business, it said.
Ten twin fluorescent lights switched on for eight hours a day produce one tonne of carbon a year, while reducing the heating temperature in an office by just 1C can save 30 tonnes of carbon a year, it continued.
CARBON ON THE MAP
Glasgow 1,052,571 (0.90)
Blackpool 202,609 (0.78)
Newry 22,507 (0.82)
Aberystwyth 6,607 (0.42)
Sheffield 682,838 (1.07)
Bristol 436,019 (0.79)
Tonnes per km square a year. Figures in brackets per head
Aberystwyth - one of the 33 urban areas used in the study - was found to have relatively low emissions as it is a student town.
Students are less likely to drive cars, and live in communal areas, which helps to keep carbon down.
The trust urged businesses to do more, adding it was able to give advice and was also able to offer medium and small businesses interest-free loans to reduce their emissions.
But the trust's Dr Garry Felgate also urged people to cut their emissions both at home and work.
For example, switching your computer off at the end of the day could make a huge difference, he said.
"What this map actually shows is that all of us are contributing to carbon emissions and it shows the scale of it by town.
"It means that each of us can release what is happening and take control and drive these emissions down."
He said he was optimistic carbon emissions would be cut in future because of two reasons.
"People are beginning to be aware of the effects of climate change and are making the link with their emissions," he said.
"But we need them to realise it is not just the emissions they see, it is the energy they use.
"Secondly, energy prices are rising. Businesses in the past thought of energy as a fixed cost. Now they see it as a fluctuating cost that they can drive down through energy savings."