The bank claims the commercial card - called Barclaycard Business Sustain - is the first in the world that facilitates the offset of a company's business air travel.

By tracking a company's spend on air travel, the card helps corporate customers to develop a clearer picture of their carbon footprint in this respect, says the bank.

Barclaycard Business manages the carbon offset process on behalf of corporate customers by providing them with commission-free access to the 'certified emission reduction market' via Barclays Capital's emissions trading desk.

Barclays Capital purchases certified emissions reductions (CERs) on behalf of the customer - which allows for the maximum amount of carbon to be offset - and then arranges for the CERs to be cancelled, effectively ensuring that the certificates are non-tradable in the future. The customer receives cancelled CER certificates.

This process essentially offsets the environmental impact of the customer's business travel, says Barclaycard.

"The environmental impact of business travel is a major issue for our corporate customers. Many of them are global companies for whom a significant amount of international air travel is simply unavoidable," says Denise Leleux, commercial cards director, Barclaycard Business. "Now, for the first time, they can have access to a corporate charge card that will provide companies - and their employees - with the opportunity to take responsibility for their carbon emissions."

Leleux says the card "provides a practical solution to help offset carbon emissions on business air travel", but it doesn't in itself reduce the carbon emissions - companies can do that only by reducing air travel.

In May Barclaycard launched a similar carbon offset card in partnership with global consultancy Deloitte. The card, which aims to offset some of the environmental impact of the goods and services purchased using the card, was rolled out to Deloitte's 11,000 staff in the UK.

This followed the release of Barclays' 'Breathe' credit card to UK customers in April. The bank donates 50% of Breathe profits to environmental projects dedicated to reducing carbon emissions around the world. Cardholders also receive discounts and lower rates on green products.

Earlier this week the UK's Co-operative Bank launched a new green credit card that offers a lower rate of interest on purchases made from selected ethical partners.

In addition, the first time the card is used, the bank will arrange for half an acre of Brazilian rainforest to be purchased and protected in the customer's name. For every £100 spent on the card a further 25 pence will be donated to protecting the rainforest.

Last year Dutch banking group Rabobank launched a 'climate credit card' that contributes funds to environmentally-friendly projects every time the card is used to pay for energy-consuming goods and services.