14 DAY TRIAL // According to a new study conducted by experts at the US National Oceanic and Atmospheric Administration (NOAA), it would appear that a recent increase in the amounts of aerosols available in our planet's atmosphere managed to offset about a third of the warming effects of carbon dioxide.
This means that the potent greenhouse gas only heated the world at 67 percent of its capacity, rather than the full 100 percent. Experts caution that this study is not meant to suggest that further warming will not occur, or that CO2 is not responsible for the effect.
Rather, the paper provides a view on the factors that may be aiding us in our struggle against this extremely dangerous phenomenon. Details of the work appear in the latest online issue of the top journal Science.
Aerosols are very small airborne particles, which can be either solid or liquid. They have the ability to reflect sunlight back into space, and can usually be found in the stratosphere 10 to 50 kilometers (6 to 30 miles) above the surface.
By reflecting solar radiation, aerosols prevent further heating of the planetary surface. They also indirectly prevent the greenhouse effect from growing in intensity. Less heat is available to the surface, which means that less heat is trapped in the atmosphere, warming Earth.
The effects of aerosols on the planetary climate is very complex, and several satellites are now being built specifically to analyze their influence. “Since the year 2000, stratospheric aerosols have caused a slower rate of climate warming than we would have seen without them,” expert John Daniel explains.
The scientist holds an appointment as a physicist at the the NOAA Earth System Research Laboratory (ESRL), in Boulder, Colorado. He is also one of the authors of the Science paper. He explains that the study covered the last 10 years exclusively.
“Stratospheric aerosol increased surprisingly rapidly [since 2000], almost doubling during the decade,” the investigator adds. He explains that volcanic eruptions are largely responsible for the vast amounts of aerosols that were injected in the atmosphere during this time.
“The increase in aerosols since 2000 implies a cooling effect of about 0.1 watts per square meter – enough to offset some of the 0.28 watts per square meter warming effect from the carbon dioxide increase during that same period,” the expert goes on to say .
Scientists from the Cooperative Institute for Research in Environmental Sciences (CIRES), the University of Colorado, NASA, and the University of Paris were also involved in the new research effort.
“The ‘background’ stratospheric aerosols are more of a player than we thought. The last decade has shown us that it doesn’t take an extremely large volcanic eruption for these aerosols to be important to climate,” Daniel concludes.