South Asian emissions of fossil fuel SO2 and black carbon increased

Clouds and aerosol particles have bedevilled climate modellers for decades. Now researchers are starting to gain the upper hand.

Data from the satellite-based Special Sensor Microwave Imager (SSM/I) show that the total atmospheric moisture content over oceans has increased by 0.41 kg/m2 per decade since 1988. Results from current climate models indicate that water vapor increases of this magnitude cannot be explained by climate noise alone. In a formal detection and attribution analysis using the pooled results from 22 different climate models, the simulated “fingerprint” pattern of anthropogenically caused changes in water vapor is identifiable with high statistical confidence in the SSM/I data.

Human activities are releasing tiny particles (aerosols) into the atmosphere. These human-made aerosols enhance scattering and absorption of solar radiation. They also produce brighter clouds that are less efficient at releasing precipitation. These in turn lead to large reductions in the amount of solar irradiance reaching Earth's surface, a corresponding increase in solar heating of the atmosphere, changes in the atmospheric temperature structure, suppression of rainfall, and less efficient removal of pollutants.

Distributions and climate impacts of biomass-burning aerosols were simulated by a global aerosol climate model, SPRINTARS, which was fully coupled to a general circulation model. The model included calculations of the direct, semi-direct and indirect effects of aerosols.

With the health of the world’s highest glaciers in dispute, an international team is planning a long-term campaign to measure the vital signs of the ice atop Tibet and its surrounding mountains.