"Aviation is really important to the global economy. We better understand what it's doing to climate because it's the fastest growing fossil fuel-burning sector and there is no alternative to air travel in many circumstances.
Emissions are projected to increase substantially in the next two decades—by a factor of two—whereas projections for other sectors are expected to decrease," said Nadine Unger, the study's author and assistant professor of climate science at the Yale School of Forestry & Environmental Studies.
Particles of sulfate, formed by burning sulfur-laden jet fuel, act like tiny mirrors that scatter solar radiation back into space. When sulfur is removed from the fuel, warming occurs but it's offset by the cooling effect of nitrate that forms from nitrogen oxides in jet exhaust. The result is that desulfurization of jet fuel has a small, net cooling effect.
In 2006 the United States introduced an ultralow sulfur standard for highway diesel, and the Federal Aviation Administration (FAA) is interested in desulfurized jet fuel for its potential to improve air quality around airports. Aircraft exhaust particles lodge in the lungs and cause respiratory and cardiovascular illness. In 2006 there were more than 31 million flights across the globe, according to an FAA emissions inventory.
"It's a win-win situation, because the sulfate can be taken out of the fuel to improve air quality around airports and, at the same time, it's not going to have a detrimental impact on global warming," she said.
Unger used a global-scale model that assessed the impact of reducing the amount of sulfur in jet fuel from 600 milligrams per kilogram of fuel to 15 milligrams per kilogram, which is the level targeted by the U.S. Department of Transportation.
The study also simulated the full impacts of aviation emissions, such as ozone, methane, carbon dioxide, sulfate and contrails—those ribbons of clouds that appear in the wake of a jet—whereas previous studies examined each chemical effect only in isolation.
"In this study we tried to put everything together so that we account for interactions between those different chemical effects," said Unger. "We find that only a third of the climate impact from aviation can be attributed to carbon dioxide."
Unger also ran a simulation of aviation emissions at the Earth's surface and found that the climate impact is four times greater because the emissions occur at altitude in the upper atmosphere.
"The chemical production of ozone is greater in the upper troposphere and its radiative efficiency is greater," she said. "It's a stronger greenhouse gas when it's higher up in the troposphere, which is exactly where aviation is making it."
The paper, "Global Climate Impact of Civil Aviation for Standard and Desulferized Jet Fuel," can be found at http://www.agu.org/journals/gl/gl1120/2011GL049289/
David DeFusco | EurekAlert!
As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation
29.03.2017 | University of Hawaii at Manoa
Researchers discover dust plays prominent role in nutrients of mountain forest ecoystems
29.03.2017 | University of Wyoming
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering