BT is launching a carbon impact assessment service to calculate the CO2 emissions of corporate customers' IT estates.

The appraisal will take into account staff work patterns including travel and IT use as well as business operations, shard services and building infrastructure to establish the organisation's carbon footprint.

Recommendations will be made on the basis of behavioural change and potential infrastructure adjustments, said BT Global Services head of sustainability Dinah McLeod.

"Large organisations have many activities that can directly or indirectly cause the emissions of carbon.

"BT can credibly and demonstrably help a customer understand the role networked IT services plays in both producing and reducing carbon footprint."

The telecoms firm has cut its own carbon emissions by 60 per cent since 1996 and has a target to shave off another 20 per cent by 2016.