SSS 2009-05-04（在线收听）

This is Scientific American’s 60-Second Science. I’m Karen Hopkin. This will just take a minute.

Climate change is the great environmental challenge facing the world today, but maybe we should start calling it “Climates Change”. Because scientists who've looked to glaciers to study the history of climate on earth have found that the Northern and Southern hemispheres have not been moving in sync. As you might imagine, glaciers are sensitive to changes in temperature. So scientists interested in the evolution of earth’s climate use these icy formations to gauge local conditions from the past.

A research team used a newfangled method for measuring rare isotopes to accurately date glaciers in New Zealand. They then compared these numbers to historic records from the Northern hemisphere and they found no correlation in the growth of glaciers above and below the equator over the past 7,000 years. While the vast majority of glaciers are now in retreat, a few down under have been growing and shrinking like a bunch of yo-yo dieters. The discovery, published in the May 1 Issue of Science, suggests that the earth’s climate doesn’t act as a single entity, but can vary from region to region, which would make certain glaciers, whether or not they wither, better long-term weather bellwethers.

Thanks for the minute. For Scientific American’s 60-Second Science, I’m Karen Hopkin.

Notes:

yo-yo dieter: A yo-yo dieter is someone who has a weight that fluctuates up and down with his or her cyclical pattern of being involved in a fad diet.Yo-yo dieting, also known as weight cycling, is a repeated loss and gain of  body weight due to excessive dieting.

down under:The term Down Under is a colloquialism referring to Australia and (less frequently)New Zealand. It locates Australia as "the land down under" because it lies totally within the Southern hemisphere.