Cost of offsetting it: £ 29.10 which contributes toward building a small-scale hydro, where energy is generated by water, in Bulgaria.
This conventional wisdom reflects an outdated preoccupation with the current account which ignores offsetting capital movements.
The tax liability is calculated by offsetting the property related expenses against the rental income.
A very good one is at the website connected with Al Gore's award-winning documentary An Inconvenient Truth, where you can quickly calculate your impact and then check out tips on reducing or offsetting it.