A Farewell to Ice: A Report from the Arctic
by Peter Wadhams
by Peter Wadhams
Please use this thread to discuss Ch. 2: Ice, the magic crystal.
In total there are 2 users online :: 0 registered, 0 hidden and 2 guests (based on users active over the past 60 minutes)
Most users ever online was 871 on Fri Apr 19, 2024 12:00 am
I'm appreciating learning the science behind these potential tipping point positive feedback mechanisms. However, I find that Wadhams is having to compromise on clarity of explanation to maintain readability. I ran some of the explanations about layers of ice past my son, who teaches high school chem and has a strong science background, and he found them suspect. I am willing to believe the author has them right, but if he is not explaining them in a depth that would convince a chemistry teacher, it makes me think his presentation could be improved. However I will have to leave those judgments to Wadhams and his editors.Robert Tulip wrote:Chapter Two is a physics and chemistry lesson about ice.
When the Arctic Sea freezes in autumn, it forms sheets of flat crystals like snowflakes in the water, which gradually link together to form a solid barrier between sea and sky. In the first year, Arctic ice gets to about 1.5 metres thick while Antarctic ice reaches 0.5 metres, depending on waves and temperature. Only the ice crystals whose plane is vertical keep growing, while those with a horizontal plane get crowded out. The salt in first year sea ice forms cells. The ice crystals themselves don’t contain salt, so this ice is about one third as salty as the sea water. The salt then gets forced out by gravity and flushing. If the ice survives through the summer, it has much less salt, and is much stronger than first year ice.
So getting rid of all the multiyear ice means the Arctic is far more fragile.