Cirrus clouds are composed mainly of ice crystals, many of which form on dust and other particles which have been lofted to high altitudes. To better understand how different particles contribute to the formation of ice crystals in these clouds, scientists have attempted to recreate the temperature and humidity conditions in which they form in controlled laboratory experiments. A key research challenge is to translate the uncertain results of those experiments to climate models, where one could try to estimate how changes in the amount and type of particles in the atmosphere impact clouds and climate. The goal of this study was to explore how the range of uncertainty we derive from experimental results influences our estimates of how much these particles warm or cool the climate.

The study found that depending on just how strong the connection one estimates between particles and their ability to form ice crystals, increasing the amount of these particles could lead to either climate warming or cooling. Because many different experimental and modeling setups yield different estimates of the strength of this particle-ice connection, it is critical that the climate science community work to better fine-tune its measurements of this important physical process, and thoroughly account for the diversity of estimates when studying aerosol impacts on climate.