Where's the Warming?
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2000 is shaping up to become one of the warmest years ever for the U.S. and for much of the world. But it could be warmer. I'm Dave Thurlow for the Weather Notebook.

Overall, the globe has warmed up a little over one degree in the past hundred years. But it should have warmed up even more, given all the greenhouse gases we've been producing. What happened to the missing heat?

It turns out the oceans are saving a good chunk of it. Scientists have tried for years to figure out how much heat is stored in the world's oceans. It's not an easy task, because the oceans are so enormous and there is so little data. Over the past few years, a team at the National Oceanic and Atmospheric Administration-NOAA--has played detective. They pulled together records scattered around the world and created a new history of the ocean's temperature from 1948 to 1998. Measuring all the way down to ten thousand feet, they found that the world's oceans have warmed up dramatically, and not just on the surface. The top thousand feet has warmed about half a degree. That's a lot of heat, since water takes more energy to heat up than air does.

But will this heat eventually go into the atmosphere? And how will it? Well, there's already one release valve you've heard about--it's called El Niño. Each time there's an El Niño, the ocean releases huge amounts of heat into the air and the overall atmosphere warms up just a bit. It tends to make winters milder across North America--except, ironically, in the Sun Belt from California to Florida. In this southern tier, El Niño often produces so much rain and clouds that the winter days are a touch cooler than usual.

Bob Henson wrote today's show, which is a production of the Mount Washington Observatory. mountwashington.org will tell you more.