Former United States Vice President Al Gore says that he “chooses to be optimistic” about the climate change negotiations presently underway in Copenhagen, and that, depending on how the meeting resolves this week, “there’s an excellent chance that we will look back from some future time and see it as a turning point.”

He’s also defiant in the face of ongoing criticism of the Copenhagen deliberations from skeptics who continue to assert that climate change is either not occurring or is a consequence of natural variability.

“The entire north polar icecap is disappearing before our very eyes,” he points out. “What do the deniers say about that? It’s been the size of the continental United States for most of the last three million years. Forty percent of it has gone in the last few decades, and the rest of it is due to go in the coming decades.”

CLICK HERE to listen to Gore’s entire quote on the signs of climate change.

(The full transcript of the interview can be seen here.)

Gore‘s comments came during a conversation we had in New York last week, that focused primarily on his latest book, Our Choice. In contrast to his previous publications, Our Choice

is less of a polemic and more of a toolkit, a low-key and informative

guide to the ways in which energy is used (and wasted) today, and how

it could be used in a society that is both more energy-efficient and

less reliant on fossil fuels.

The Tinfoil Hat Brigade will be disappointed that the book’s 400-plus pages contain no rallying cry for – indeed, nary a mention of – the establishment of a world government under the auspices of the United Nations, although such absence is unlikely to lure them from the comforting blanket of their paranoia. Indeed, arguably the book’s most significant feature is the matter-of-fact nature of what is essentially a primer on energy, as well as the economics and politics that surround its production and use.

“I felt that the time had come to move beyond a description of exactly what we’re facing and why to a discussion of how we can solve it,” Gore said. “I did my best to capture the consensus view of what the state of the art is for solar, wind, geothermal energy, sustainable agriculture and the rest.”

CLICK HERE to hear Gore explain why he thinks global warming is harder to understand than other kinds of threats.

(The full transcript of the interview can be seen here.)

Gore possesses both pragmatism and idealism; he is skeptical of what is achievable domestically in the present – “I’ve spent enough time in the political system to have some feelings about what’s likely and what’s not” – but optimistic about what he sees as signs of notable progress. “When I was at Kyoto 12 years ago, virtually no heads of state were there,” he recalled. “Now, most of them will be. The European Union has already implemented a plan. Japan has implemented a plan. China has put out targets for reductions. So has India. So has Brazil.”

While he is perhaps more sanguine about the pace of that progress than some, he is clear on the need for its rapid continuation.

“This is the first time that we as human beings have had to make a global choice about the future of our civilization,” he said. “And what we’re facing is a global threat unlike any other in previous history. And yet we have a choice available to us, that would make our civilization more prosperous, more humane, more enjoyable, fairer, while simultaneously defusing this threat to our future.”