I would like to do a quick plug for my friend’s company clear-offset.com.  Clear is a one-stop shop to help you tackle climate change. Measure your carbon footprint, get advice on how to reduce it, and then find out how offsetting can create further reductions elsewhere.

Clear only uses Certified Emission Reduction certificates (CERs) authenticated by the United Nations Clean Development Mechanism. This is the method currently endorsed by the UK government and ensures that every tonne of emissions reduction is actually achieved.

Here is little image if you have having problems understanding all this: