Mr Pugh, who currently works in London, has taken up the Thames challenge to draw attention to a campaign by environment organisation WWF (formerly World Wildlife Fund) to stop climate change.

BBC: NEWS | UK | England | Swimmer planning Thames challenge

Vice Chair Gary Yohe is part of the World Wildlife Fund (WWF) Climate Witness Program.

FORBES: Is It Hollywood Or Washington? Global Warming Activists Control Government Climate Report

In the wild, it is the most widespread species of gorilla, according to the World Wildlife Fund (WWF), with a estimated population of 100-200, 000 individuals.

CNN: First gorilla genome map offers clues to human evolution

The World Wildlife Fund (WWF) is a good example.

FORBES: Branding for Nonprofits: New Research, New Insights

Chris Howe, head of future landscape for the World Wildlife Fund (WWF), says the group has been campaigning for stricter application of the Habitats Directive for all member states, since its introduction in 1992.

BBC: UK 'failing to protect wildlife'

Savanna elephant populations in the Central African Republic are believed to have plummeted from around 80, 000 just 30 years ago to a few hundred today, according to WWF, formerly known as the World Wildlife Fund.

CNN: Cameroon elephant slaughter latest in string of killings

For starters, the World Wildlife Fund (WWF) says the global fishing fleet is 2.5 times bigger than "what the oceans can sustainably support" - i.e. there are too many boats catching too many fish, and not giving fish stocks enough time to replenish them.

CNN: All about: Global fishing