Clouds

ENSO events also exercise a strong influence on monsoons, and on the movements of our old friend the Intertropical Convergence Zone. //The word monsoon comes from the Arabic word ‘mausem’ (season). The monsoon is a season of rains borne on dark nimbus clouds of summer that blow in from the southwest. A huge air circulation determines the intensity of the monsoon, which moves north in the Northern summer, southward in winter. In a good monsoon year, rains showers fall throughout western India and Pakistan from June to September, sometimes into November with the retreating monsoon. Millions of tropical farmers depend on this circulation. Today, highways, railroads and at least rudimentary infrastructure protects many such communities from the worst of monsoon failures. But what happened in the past when the unpredictable dark clouds never massed and the monsoon failed? With almost mind-numbing regularity, subsistence farmers died by the millions. The historian Mike Davis has estimated that between 30 and 50 million tropical villages between the Sudan and northern China perished of drought, famine, and disease during the nineteenth century, more than in all that century’s wars put together. Twenty-one out of twenty-six droughts since 1977 have been attributed to El Ninos, the most severe also coinciding with heavy snow cover in Eurasia, but the effects of ENSO events on monsoons vary considerably. - page 171