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.

—Karen Hopkin