1. Al Gore didn't say this, James Anderson did. James Anderson is a "Harvard University professor of atmospheric chemistry best known for establishing that chlorofluorocarbons were damaging the Ozone Layer."
2. You're right about the rhetoric - it has been around for centuries but so have major ecological disasters. The Dust Bowl alone forced tens of thousands of poverty-stricken families to abandon their farms, unable to pay mortgages or grow crops, and losses reached $25 million per day by 1936 (equivalent to $450,000,000 in 2018).[0] I can hardly fathom the true cost of something that impacts the entire planet.
Their latest modelling studies indicate northern polar waters could be ice-free in summers within just 5-6 years. Professor Wieslaw Maslowski told an American Geophysical Union meeting that previous projections had underestimated the processes now driving ice loss.
Could, not would. Like smoking can kill you, not smoking will kill you. It is a common and fundamental English language pattern, clearly indicating doubt and should never be misinterpreted as certainty.
Fair enough, but could is enough to play on people's fears. Immigrant X could be a terrorist. Food additive Y could cause cancer. You can't then claim you didn't say "would".
Note that things like tobacco cancer warnings use use can/could not will/would, and the intent of the message is still clear.
"SURGEON GENERAL WARNING: Cigar Smoking Can Cause Lung Cancer And Heart Disease."
2. You're right about the rhetoric - it has been around for centuries but so have major ecological disasters. The Dust Bowl alone forced tens of thousands of poverty-stricken families to abandon their farms, unable to pay mortgages or grow crops, and losses reached $25 million per day by 1936 (equivalent to $450,000,000 in 2018).[0] I can hardly fathom the true cost of something that impacts the entire planet.
[0]: https://en.wikipedia.org/wiki/Dust_Bowl