To understand how climate change is helping destabilize one of the world's most famous mountains, Stephan Gruber of the University of Zurich offers a culinary visualization.
Imagine a piece of bread - or perhaps even better, a thick cut of raw steak - in an oven. Put a stick of frozen butter on top of it. And then turn the oven on.
Two things happen:
The outside of the steak begins to cook relatively quickly. The inside stays raw for longer.
At the same time, the butter begins to melt - and seep into the steak.
Now, imagine that the steak is the mighty Matterhorn mountain, one of the most picturesque in Europe (and, yes, some of you may know it better as Disneyland's original rollercoaster).
Climate change works in three ways:
As the world gets warmer - as the oven heats up - the outside of the Matterhorn heats up (the outside of the steak cooks). That, by itself, slowly breaks apart the ice that holds the mountain's exterior rock surface together. So we are beginning to see more rock falls than ever before. (In 2003, a massive rock fall stranded 50 climbers.)
Then, the butter starts melting. The butter is actually that same ice that holds much of the mountain together. As it melts, it seeps down into ice that doesn't see the sun - say, the center of the steak - and helps cook it from the inside.
Thirdly, slowly but surely, the oven heat finally reaches the middle of the steak. Climate change finally helps warm the inside of the mountain.
And slowly but surely, the integrity of the mountain starts to diminish, both from the outside and from the inside-out.
Before you think that this is some obscure thing that happens in places with very, very high elevations, consider this: The mountains where this is happening are located where millions of people - many in Asia - actually live.
Gruber recently released a study of how this happens - the first to show that typical patters of movement of ice exist on mountains like the Matterhorn.
"You can't change topography very quickly. You can't change geologic structure very quickly," Gruber said in a phone interview. "But with global warming, you can very quickly change the ice" that holds the mountain together.
And that threatens one of the world's most beautiful icons.