“Governments talk, cities act” said New York Mayor Michael Bloomberg, quoted with approval by Sir Richard Leese, Leader, Manchester City Council yesterday at the MACF event yesterday.

MACF is Manchester: A Certain Future and brings together an effective change-based partnership of people from a mix of politics, business, community, arts, education, faith and public bodies to develop and enact changes within Manchester that will urgently push down the city’s CO2 emissions.

The event yesterday was a stock-take on progress since 2009 and workshops to explore the “next big things” that the city can achieve together.

One area where the city does need to make further progress, and quickly, is in reducing the energy use of our commercial buildings. In the discussions it was noted that the energy costs are a small fraction of occupation costs, especially in the city centre where rent plus all charges may be up to £50 per square foot, whereas the energy costs may be less than £2 of this.

The downside is that it is sometimes hard to make a financial case on such a small margin, was the feeling of the key property people present.

However, a possible upside is that the risks of financial loss are therefore also small. If this was a costed PR project rather than a costed energy-saving project, the cost/benefits would be highly attractive when compared with other PR options.

The trick could well be to obtain the PR return on investment as a result, and one approach here is to have a DEC – display energy certificate – in the lobby or even better in the front window, to show competitors and attract responsible customers.

Having good evidence is key to making city-change work to its best effect. New York Mayor Michael Bloomberg has also said that, “On the US dollar note it says ‘In God we trust’, however everybody else has to bring data.”