The green agenda is at risk of being sidelined by the credit crisis, in spite of attempts to keep issues alive in the commercial property industry. The environmental impact of commercial property is undeniable, with about half of all Britain's carbon emissions associated with buildings, according to government figures. Corporate property is thought to be responsible for as much as a fifth of global CO 2 emissions, through energy use, waste and water production. This is equivalent of the average annual car use of 90m people. With almost 50 per cent of a company's CO 2 emissions believed to be produced by its real estate, it is no surprise that property offers one of the most direct ways for those with stringent corporate social responsibility codes to make a difference. However, a recent study of more than 100 directors responsible for real estate by Knight Frank showed that concerns about the environment and energy efficiency had fallen to the bottom of the agenda. On a list of the 10 most important factors when considering a building, sustainability was 10th. The top issues were rental cost and staff retention, perhaps unsurprisingly given the pressures on many businesses as the economy stalls. With tenants no longer focused as much on the desirability for green buildings, the impetus could also be lost among developers and property owners, who may be worried about higher costs in a market where prices are already under pressure. It had been hoped that higher rents would be possible on modern green buildings. But with costs up by as much as a quarter, says consultancy Savills, and commercial property hit by taxes such as empty rates, there is less incentive for developers to go "green". A survey of the attitudes of the UK's leading investors by GVA Grimley showed that "very modest" progress had been made towards increasing the sustainability of property within investment portfolios over the past year. To a certain extent, the industry is having to reform some of its polluting ways because of increasingly strict regulations, although some feel the UK government's policy has not been effective. It has introduced various means of improving the carbon footprint of buildings, including mandatory energy performance certificates, which landlords have to obtain to provide an energy rating of their buildings, as well as the non-compulsory Breeam (Building Research Establishment Environmental Assessment Method) ratings. Another industry initiative is the so-called green leases, which aim to help create a partnership between landlord and tenant in cutting emissions. Hermes, for example, is redrawing many of its leases to include "green" clauses that encourage tenants to help reduce the impact of its buildings. Siobhan Cross, a property partner at Pinsent Masons a law firm, says the most important event will be the government's climate change bill, which includes targets for 26 to 32 per cent carbon emissions reduction by 2020 and 60 per cent by 2050. Ms Cross says the bill includes a mandatory carbon trading scheme that will affect large owners and occupiers with direct electricity bills of more than