Last September 21, as the Northern Hemisphere tilted away from the sun, scientists reported with unprecedented
distress that the North Polar ice cap is "falling off a cliff."
One study estimated that it could be completely gone
during summer in less than 22 years. Another new study,
to be presented by U. S. Navy researchers later this week,
warns it could happen in as little as 7 years.
What type of appeal does Gore mostly use to persuade the audience?