Saturday, March 20, 2010

Global warming -- a reprise

"Goodness," thought Alice to herself, "what a very strange place this is."

Only a moment before, the sun had been shining brightly and Alice was quite comfortable in her pinafore. Now the snow was falling furiously, and lay on the ground as high as her waist.

"I shall catch my death of cold," she said to no one in particular.

No sooner had she spoken than the sun burst through the clouds and the snow melted away. Soon she was standing up to her ankles in water.

"What could possibly happen next?" she thought. Whereupon dark clouds covered the sun and hailstones as big as hedgehogs splashed into the flood.

"Tornado, tornado!" she heard someone cry in a small, squeaky voice. The Dormouse came swimming by in a bit of a panic. Alice looked in the direction from which he had come and saw a dark twister scattering shrubs and houses and teapots every which way. Immediately, the water subsided and the ground became parched and arid.

"Global warming," said a confident voice.

Alice turned to see a large blue caterpillar sitting upon a mushroom. "Who are you?" she asked.

"Too much carbon dioxide in the atmosphere," said the Caterpillar between big smoky puffs on his hookah. "Cutting down rain forests. Burning fossil fuels..."

He exhaled a dense cloud of blue smoke. "It's a scandal."

"Then why are you smoking?" coughed Alice.

"Ah," said the Caterpillar, "my little bit of smoke won't make a difference. It's the big corporations, you see. The farm interests. The..." He paused to exhale. "The sea is rising. If I were you, I'd find a nice tall mushroom and stay put."

"Global warming? Rising seas?" wondered Alice. "I do wish I had an expert who could tell me the cause of the capricious weather."

And just as this thought passed through her head, she noticed two identical little scientists in white lab coats standing under a tree. One scientist had "Tweedlehigh" printed on his pocket-protector; the other scientist's pocket-protector read "Tweedlelow."

"Can it possibly be true," she asked, "that the world is getting hotter, and that the sea is rising?"

"Indeed, it can," said Tweedlehigh. "The amount of carbon dioxide in the atmosphere increases every year, and the global mean annual temperature has risen by more than a degree in the last century. There will be a two or three-degree change in the next hundred years. Sea level will rise as the ocean expands thermally and glacial ice melts. We can expect crazy permutations in the weather."

"Contrariwise," said Tweedlelow, "the present aberrations in the weather are statistical flukes, no different than extremes we have had in the past."

"Contrariwise," said Tweedlehigh, "my computer models show that small increases in carbon dioxide in the atmosphere significantly affect global climate, sea level, rain patterns..."

"Contrariwise," interrupted Tweedlelow, "computer models are not nearly sophisticated enough to describe the real climate system. There are too many variables. Too many kinds of feedback..."

"Contrariwise," shouted Tweedlehigh, "my model includes atmospheric composition, changes in ocean circulation and biochemistry, incoming and outgoing radiation, vegetation, atmospheric circulation, clouds..."

"Contrariwise," cried Tweedlelow, "clouds are too complicated -- an enormous variety of types, variability on all spatial scales, from sub-millimeter to thousands of kilometers, and time scales, from microseconds to weeks. The amount of cloud cover depends on sea temperature, atmospheric pollution, plants. No computer model yet devised can adequately model clouds. And then there's the deep sea. It takes thousands of years for the deep sea to come into equilibrium with surface changes..."

"Contrariwise," roared Tweedlehigh, "my ocean model has one degree resolution in latitude and longitude, and 100 levels in the vertical! It includes sea ice..."

"Contrariwise," thundered Tweedlelow, as he thumped Tweedlehigh with a large barometer.

"Contrariwise," stormed Tweedlehigh, as he adjusted a brass rain gauge on his head as a helmet.

The two scientists went tumbling off into the woods, head over heels, shouting and pummeling each other fiercely.

Suddenly, the hot sun was eclipsed by clouds and it started raining, a drenching deluge. "What a very strange place this is," thought Alice somberly, as raindrops the size of wrens' eggs splashed into the flood.