SINGAPORE — Scientists have developed an extensive understanding of the impact that carbon dioxide, methane, nitrous oxide and other global warming gases have on Earth's climate.

These are large-scale emissions from human activity such as burning coal, oil and natural gas, and clearing forests for farming, urban growth and industry.

However, much less is known about the impact of aerosols on the climate. Aerosols are tiny liquid and solid particles suspended in the atmosphere. They come in many different forms, from both man-made and natural sources.