There is a paradox at the heart of our changing climate. While the blanket of air close to the Earth’s surface is warming, most of the atmosphere above is becoming dramatically colder. The same gases that are warming the bottom few miles of air are cooling the much greater expanses above that stretch to the edge of space.
This paradox has long been predicted by climate modelers, but only recently quantified in detail by satellite sensors. The new findings are providing a definitive confirmation on one important issue, but at the same time raising other questions.
The good news for climate scientists is that the data on cooling aloft do more than confirm the accuracy of the models that identify surface warming as human-made. A new study published this month in the journal PNAS by veteran climate modeler Ben Santer of the Woods Hole Oceanographic Institution found that it increased the strength of the “signal” of the human fingerprint of climate change fivefold, by reducing the interference “noise” from background natural variability. Sander says the finding is “incontrovertible.”
But the new discoveries about the scale of cooling aloft are leaving atmospheric physicists with new worries — about the safety of orbiting satellites, about the fate of the ozone layer, and about the potential of these rapid changes aloft to visit sudden and unanticipated turmoil on our weather below. [Continue reading…]