RESUMO
Droughts have become more severe and recurrent over the Indian sub-continent during the second half of the twentieth century, leading to more severe hydro-climatic and socio-economic impacts over one of the most densely populated parts of the world. So far, droughts have mostly been connected to circulation changes concomitant with the abnormal warming over the Pacific Ocean, prevalently known as "El Niño". Here, exploiting observational data sets and a series of dedicated sensitivity experiments, we show that the severity of droughts during El Niño is amplified (17%) by changes in aerosols. The model experiments simulate the transport of boundary layer aerosols from South Asian countries to higher altitudes (12-18 km) where they form the Asian Tropopause Aerosol Layer (ATAL) (~ 60-120°E, 20-40°N). During El Niño, the anomalous overturning circulation from the East Asian region further enriches the thickness of aerosol layers in the ATAL over the northern part of South Asia. The anomalous aerosol loading in the ATAL reduces insolation over the monsoon region, thereby exacerbating the severity of drought by further weakening the monsoon circulation. Future increases in industrial emissions from both East and South Asia will lead to a wider and thicker elevated aerosol layer in the upper troposphere, potentially amplifying the severity of droughts.
RESUMO
Beginning with a discussion of the sources in Darwin's writing for Freud's theory of the hysterical symptom, this essay proceeds to a symptomatic reading of Darwin himself. With reference to "The Origin of Species," "The Descent of Man," and "The Expression of the Emotions," this essay shows that Darwin's theories of involuntary expressive behavior and of aesthetic preference in sexual selection are linked by their role in his understanding of racial difference and also by their reliance on the idea that learned habits can be inherited as instincts, a view often identified with Lamarck. They are thus at once theories of the foreign body and theories that appear as foreigners within the body of Darwin's work.
