Fact sheets


Action needed

Civil disobedience



About us


This website was launched in 2007 to give unbiased information on carbon dioxide emissions, climate change, and how to become independent of fossil fuels. The calculator is constructed according to the best information available to us, and we will update it as new information becomes available.

We both trained as doctors. One of us (Ian Campbell) now works as a medical statistician and on sustainable projects. Margaret Campbell works on a number of environmental projects.

We have no financial interest in this area. We have constructed this site because we care about what is happening to our world, and are concerned about the future of our children and future generations.

Thanks are due to Helen, Debbie, Peter, Carol, Geraldine, Clive, Andrew, Patrick, Ann, Gen and John for feedback on earlier versions of this calculator.


  • one of three recommended by Ethical Consumer Magazine (Nov/Dec 2007 issue) in the "Best Overall Online Calculators" category.
  • one of the calculators recommended by the Newsletter of Women's Environmental Network (Winter 2007 issue)
  • recommended by The Three Tonne Club Handbook (2008)

Contact us

Comments on any aspect of this website are welcome.

We aim to give a fair summary of the evidence, and give unbiased conclusions. If we have omitted important considerations, or not given them due weight, please let us know.



Evidence of the severity of the drought in Kenya - this was marked on the map as a river.

First published Feb 2007
Last updated: 20 Nov 2018