Positive Cloud Brightening Results from E-PEACE

In 2011, a multi-institutional marine cloud brightening (MCB) research project called the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) conducted a series of small-scale, low-level cloud particle experiments off the coast of California.  Details of these trials and experimental results are  now being shared.  Tests were conducted using three different particle technologies: larger aerosols from conventional ship exhaust (known to produce observable ship tracks), smaller aerosols from dedicated shipboard smoke generators, and salt particles released from aircraft.  The research team was able to establish that specialized smoke generators successfully create reflective tracks, and do so much more efficiently than ship exhaust (results for salt particles are not yet available).  Scientists also found that low clouds and multiple layers reduce the effectiveness of aerosol emissions.  The overall conclusion reached by researchers was that "The E-PEACE results provide a proof of concept that cloud brightening to reduce global mean warming is possible, with existing, decades-old technology, for some cloud conditions" (p. 14).