New research from the University of Michigan shows that satellite-based projections of aerosols' effect on Earth's climate significantly underestimate their impacts.
The findings will be published online the week of Aug. 1 in the early edition of the Proceedings of the National Academy of Sciences.
Aerosols are at the core of "cloud drops"---water particles suspended in air that coalesce to form precipitation. Increasing the number of aerosol particles causes an increase in the number of cloud drops, which results in brighter clouds that reflect more light and have a greater cooling effect on the planet.
As to the extent of their cooling effect, scientists offer different scenarios that would raise the global average surface temperature during the next century between under 2 to over 3 degrees Celsius. That may not sound like a broad range, but it straddles the 2-degree tipping point beyond which scientists say the planet can expect more catastrophic climate change effects.
The satellite data that these findings poke holes in has been used to argue that all these models overestimate how hot the planet will get.
"The satellite estimates are way too small," said Joyce Penner, the Ralph J. Cicerone Distinguished University Professor of Atmospheric Science. "There are things about the global model that should fit the satellite data but don't, so I won't argue that the models necessarily are correct. But we've explained why satellite estimates and the models are so different."
Penner and her colleagues found faults in the techniques that satellite estimates use to find the difference between cloud drop concentrations today and before the Industrial Revolution.
"We found that using satellite data to try to infer how much radiation is reflected today compared to the amount reflected in the pollution-free pre-industrial atmosphere is very inaccurate," Penner said. "If one uses the relationship between aerosol optical depth---essentially a measure of the thickness of the aerosols---and droplet number from satellites, then one can get the wrong answer by a factor of three to six."
These findings are a step toward generating better models, and Penner said that will be the next phase of this research.
"If the large uncertainty in this forcing remains, then we will never reduce the range of projected changes in climate below the current range," she said. "Our findings have shown that we need to be smarter. We simply cannot rely on data from satellites to tell us the effects of aerosols. I think we need to devise a strategy to use the models in conjunction with the satellite data to get the best answers."
The paper is called "Satellite-methods underestimate indirect climate forcing by aerosols." The research is funded by NASA.
PNAS Early Edition: http://www.pnas.org/content/early/recent
Joyce Penner: http://aoss.engin.umich.edu/people/penner
The University of Michigan College of Engineering is ranked among the top engineering schools in the country. At $180 million annually, its engineering research budget is one of largest of any public university. Michigan Engineering is home to 11 academic departments, numerous research centers and expansive entrepreneurial programs. The College plays a leading role in the Michigan Memorial Phoenix Energy Institute and hosts the world-class Lurie Nanofabrication Facility. Michigan Engineering's premier scholarship, international scale and multidisciplinary scope combine to create The Michigan Difference. Find out more at http://www.engin.umich.edu/
New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences