Fears of a bright planet

摘要

Shiny things absorb less heat when left in the sun. This means that if the Earth could be made a little shinier it would be less susceptible to global warming. Ways to brighten it, such as adding nanoscale specks of salt to low clouds, making them whiter, or putting a thin haze of particles into the stratosphere, are the province of "geoengineering". The small band of scientists which has been studying this subject over the past decade or so has mostly been using computer models. Some of them are now proposing outdoor experiments-using seawater-fed sprayers to churn out particles of the exact size needed to brighten clouds, or spewing sulphur particles from underneath a large balloon 20km up in the sky.