New software to measure carbon emissions at street level

The system developed by US researchers could help identify the most effective places to cut emissions as it combines information from public databases with traffic simulations and energy consumption models, the BBC News reported.

Scientists from the Arizona State University developed the new measuring system, called Hestia using data from a number of sources including air pollution reports, traffic counts and tax offices.

It was then combined with a modelling system for quantifying CO2 emissions down to individual building level.

Dr Kevin Gurney, one of the leaders of the project told the BBC that his team knows the system is working because it is consistent with exisiting information on emissions.

"We can go to any city in the US and do the quantification and we know it will be utterly consistent from city to city and consistent from city all the way up to national level," he said.

So far the system has been used on Indianapolis and work is ongoing with Los Angeles and Phoenix. The researchers are learning a great deal about emissions in the urban environment.

"You realise how large a source electricity production is. It tends to swamp the signal in cities. And things like traffic jams and slow downs in traffic, that's what really hits you," said Gurney.

Scientists behind the system say it can be extremely useful for cities, helping them to target where to make emissions cuts.

Once those cuts have been made, the system can verify their effect. Verification is also a hugely contentious issue at international negotiations on a global climate treaty.

Many developed countries are concerned that any cuts in carbon agreed by developing nations might not actually happen.

"Right now we are exploring the use of remote sensing but the nice thing is that now we can use Hestia to calibrate the remote sensing in the cities we have done. Through that we may be able to infer a lot better estimate of emissions in Rio or Delhi," he said.

The researchers believe that the system can be used to give greater credibility to carbon trading.

"Nobody buys a stock that's ten dollars plus or minus five dollars. We have to have confidence in the numerical value of something. We have to have the same level of confidence about a unit of emissions," said Gurney.

Details of the new system are published in the journal Environmental Science and Technology.