The 24 best companies to invest in if you care about not destroying earth

London-based startup ET Index is trying to encourage "green" investment by providing investors with carbon emission data and tracking, both for portfolios and individual companies.

The company tracks direct greenhouse gas emissions, as well as factoring in things like electricity consumption, supply chain, and other indirect emissions.

ET Index has produced a live ranking of 800 biggest companies in the world, based on relative emissions and weighted to allow comparison of the biggest to the smallest on the list.

Each business is given an intensity score, which gives the tonnes of carbon dioxide equivalent produced per $1 million (£650,000) in revenue. The worst performer produces 62,120 tonnes per $1 million, the best just 910.

Check out the 24 best performers, with the lowest carbon emissions to revenue ratios.