Father of three Howard Balmer, 42, is supporting the Climate Justice Fast which is being undertaken by a number of activists around the world during the United Nations Climate Change Conference in Copenhagen (COP15).
COP 15 is said to be the largest and most important UN climate change conference in history, with diplomats from 192 nations warned that this could be the last chance for a deal to protect the world from calamitous global warming.
The Climate Justice Fast group has called for world leaders to adopt a globally binding treaty with the most rapid possible transition to safe levels of atmospheric greenhouse gases and significant funds for those most affected by climate change.
Seven members have been surviving without food, just water, since November 6 and intend to continue for a total of 42 days, when the conference ends.
In support, Howard is one of five Cornish environmental campaigners who started a fast on Monday. He is being joined by Cerianne Edwards from Treyarnon, Alastair Russell from Wadebridge, Klaudia van Gool from Liskeard, Oliver Baines from Ladock and Benjamin Simpson from Truro.
Howard said: "The courage and strength of those on hunger strike deeply affected me and I wanted to show my support with a personal commitment, so I'll be fasting for a week during the upcoming Copenhagen climate talks.
"I have set myself the challenge to fast for at least seven days but might extend it to 12 depending on how well I survive. I think it is vitality important to flag up the importance of climate change not only to the world leaders but also to the man on the street. We need to put pressure on everyone to make changes now to help the future of the planet for our children an future generations. Some people just do not understand the seriousness of climate change.
"The worst climate impacts are being felt in the developing world; the poorest nations that have played no part in creating our climate crisis are being hit first and hardest. The cost of these nations adapting to their current situation is rising rapidly, it currently stands at approximately $195 billion.
"It's about making a commitment, about saying I'm prepared to make a sacrifice to ensure that vulnerable people are protected and that our kids inherit an earth worth having."
The core hunger strikers intend to fast at least until the end of the Copenhagen talks, which conclude on December 18 and several hunger strikers will be present inside the UN climate summit.
● For more reports on the Copenhagen summit see Page 22.