After allowing for humidity and rainfall, they found that «aerosol optical thickness» — a measure of the
concentration of atmospheric particles — decreased by only 10 to 15 per cent compared with the same periods in 2002 to 2007 (Geophysical Research Letters, in press).
This Hot Paper provides a foundation for global
studies of atmospheric particles from human activities and other sources, which play an important role in the Earth's climate system, but their effect on the climate is still one of the largest sources of uncertainty in model predictions of climate change.
The same goes for the stampede on clouds and climate following publication of an important, but preliminary, laboratory finding from the European Organization for Nuclear Research (better known by its acronym, CERN) about how cosmic rays can stimulate the
formation of atmospheric particles (an ingredient in cloud formation).