Grains of salt

摘要

There is something captivating about the idea that fine paniculate matter, suspended almost invisibly in the atmosphere, holds the key to some of the greatest mysteries of climate science. Recent studies have reported that interactions of such aerosols with clouds may be hiding a large part of the sensitivity of global temperature to increasing levels of greenhouse gases1. It has also been claimed that aerosol-cloud interactions are reshaping patterns of rainfall2 and even influencing the development of tornadoes3. But such interactions invariably turn out to be more nuanced than the simple ideas underpinning these and related studies would lead one to suspect.