By Scott Harris
For The Chronicle-Journal Oct 12, 2017
THAT’S what they say. Who are they? Well, geophysicist Henry Pollack for one.
In his book A World Without Ice, Pollack explains the delicate geological balance between the Earth and its ice, and why it is important that we humans pay attention to this balance, especially since human activity is accelerating the planet’s race toward a tipping point with respect to its ice.
Ocean floor core samples reveal that the last time Earth was free of ice was 55 million years ago, when the greenhouse gas methane warmed the atmosphere, melting the polar ice sheets and reducing the planet’s ability to reflect solar energy back into outer space.
We currently live in what scientists describe as a Goldilocks environment, not too hot and not too cold. As we look for life on other not-so-fortunate planets, we can see clearly that indeed we are a Goldilocks planet – not too close to the sun to lose all of our water to evaporation, or far enough away to be just another snowball rocketing through space.