TOKYO: Strong storms will become stronger while weak storms become weaker, and the cumulative result of all the storms will remain unchanged under global warming, says a study led by atmospheric physicists at the University of Toronto.
The team quantified the way in which increase in water vapour from global warming influences the strength of atmospheric air circulation.
The atmosphere it turns out will adapt to hotter, wetter climate.
“We know that with global warming we’ll get more evaporation of the oceans,” said Frederic Laliberte, a research associate at U of T’s physics department and lead author of a study published in Science.
“But circulation in the atmosphere is like a heat engine that requires fuel to do work, just like any combustion engine or a convection engine.”
The warmer the air mass, the more water it takes up from the surface. As it reaches the Equator, it begins to ascend through the atmosphere, cooling as it expands and sending heat out into space.
Since cool air can hold less moisture than warm air, condensation occurs, releasing heat. When enough heat is released, air begins to rise even further, pulling more air behind it producing a thunderstorm.
This is the way heat and moisture is redistributed between the Equator and the North and South Poles.
The scientists concluded that the increase in water vapour from global warming was making the process less efficient by evaporating water into air that is not already saturated with water vapour.
This inefficiency limited the strengthening of atmospheric circulation, though not in a uniform manner.
Air masses that are able to reach the top of the atmosphere are strengthened, while those that cannot are weakened.
