Basel, Switzerland (CNN) A 104-year-old Australian scientist who is set to end his life at a clinic in Switzerland later this week told CNN that his life was no longer worth living and said he hoped his story would lead to the legalization of assisted dying in other countries.

David Goodall, a respected botanist and ecologist, is due to die at the Life Circle clinic in Basel on Thursday, after traveling to Europe from his home town of Perth, Australia earlier this month.

The grandfather-of-12 and longtime member of pro-euthanasia group Exit International said his life stopped being enjoyable "five or 10 years ago," in part because of his failing mobility and eyesight.

"My life has been out in the field (working), but I can't go out in the field now," said Goodall, who must be pushed everywhere in a wheelchair, during an exclusive interview with CNN in his hotel in Basel on Tuesday.

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"I would love to be able to walk into the bush again, and see what is all around me," said the father-of-four, who during his long life has had three wives and moved to Australia from London as a child.

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