House Concerts York is a carbon neutral website:

As part of our commitment to reducing our impact upon the environment, House Concerts York have offset the CO2 generated from our web servers each year.

House Concerts York operate a dedicated web server, which emits approx 0.2 tonnes of CO2 each per year. Ideally we'd like to reduce this initial carbon footprint, however we're currently limited by available technology and our suppliers.

The next best alternative is to offset emissions which cannot easily be reduced. By investing in a carbon offset program, we aim to remove the equivalent volume of CO2 from the atmosphere, resulting in carbon neutral hosting

You can find more details about the Carbon Offset projects at the Climate Care website.