When the renowned wildlife photographers Jonathan and Angie Scott first visited the Antarctic 15 years ago, at the beginning of the continent's summer in early November, they could see the pack ice from their expedition ship.
But when they returned in later years they had to arrive ever earlier to see the ice. And on their last visit, in 2006, the only way they could get up close was to board a Russian icebreaker. In a lecture to the Royal Geographical Society tonight, Jonathan Scott, who with his wife has spent years capturing the beauty of the Antarctic on camera for a book, Antarctica: Exploring a Fragile Eden, will warn of the devastation man is wreaking on this most remote, inhospitable and awe-inspiring of continents.
He will call for the terms of the 1959 Antarctic Treaty, which dedicated the polar region to peace and science, to be respected, and he will question the UK's plan to claim sovereign rights over a large area of the seabed off Antarctica.
"If you can't protect somewhere like the Antarctic which would appear to be so remote, that's got to be a wake-up call to us all," he will say. "Antarctica represents the most hostile, uninhabitable place. It's a great irony that here is this landscape which seems to be indestructible, which could disappear.""
Environmentalists have condemned the Government's intention to extend British oil, gas and mineral rights in the Southern Ocean. Such a claim would be in defiance of the Antarctic Treaty, to which the UK is a signatory, stating that no new claims will be asserted on the continent.
Scott, best known for his photographs of big cats in the Masai Mara Game Reserve in Kenya, where he and his wife live, also warns that over-fishing of squid and krill is contributing to a decline in several species, particularly elephant seals.
Jonathan Scott will lecture at the Royal Geographical Society in London at 7.30pm. Tickets at £12 are available by calling 0845 430124.