This study from Yale University seems contradictory to what we know about aerosols. Generally more aerosols like SO2 cool the climate, but in this case they are saying “it’s offset by the cooling effect of nitrate that forms from nitrogen oxides in jet exhaust.” Interesting.
Removing sulfur from jet fuel cools climate
A Yale study examining the impact of aviation on climate change found that removing sulfur from jet fuel cools the atmosphere. The study was published in the October 22 issue of Geophysical Research Letters.
“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/.
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“The result is that desulfurization of jet fuel has a small, net cooling effect.”
They think it has a cooling effect. Does reality agree?
WT*, not doing something that causes cooling, causes warming?
Interesting stuff. I have a host of questions that can only be answered by examining the paper all these models. Perhaps it is just the press release language but I do not get the impression that these “climate effects” are important as they do seem to be rather small and for CO2 getting even smaller.
How in this world did so many people get fooled into thinking it’s too hot…………..
http://www.americanthinker.com/%231%20CO2EarthHistory.gif
In other words… We conjecture, that this will effect other conjecture. Which will result in additional conjectured effects. Those effects will have a conjectured impact on the economy and health.
Am puzzled by these results. Radiative effects are negligible in the troposphere …what are they talking about?
I did some digging the other day. I found that Tynsdall who proved greenhouse warming did so back in 1859, NOT 1959. What sort of scientific replication has been done since then to prove or disprove. In a lab?
Sounds like not everything was taken into account in their computer model. (Duh.)
Engine manufacturers have been working on reducing nitrogen oxides, and thus nitrates, for quite a while, and with good success. They aren’t going to get near as much ‘beneficial’ cooling from nitrates as they expect.
Sulfur removal is just another added expense to air travel.
Unger used a global-scale model…
The study also simulated…
Unger also ran a simulation…
Models and simulations followed by illogical pragmatic statements… where do we know that from?
I assume some major corporation has a sulfur-removal product waiting “in the wings”, so to speak.
Well, of course, there are alternatives to jet travel, but thanks to that idiotic Titanic film, people are a little leery of vast passenger liners. Same with rigid airships. Technology exists to make both modes of travel much safer than 80-100 years ago, but we have become used to the convenience of regularly scheduled, low-density air travel.
Ironically, I can foresee a gradual decline in air travel as it is currently done to an “on-demand” model, where the plane doesn’t leave until the seats are filled, along with a simple decline based on fuel prices and a lessened need for business travel in an increasing age of “telepresence” and virtual networks. Climate change might not enter into those equations, or at least not as the driving (no pun intended) consideration. Jet travel may become a niche industry, like paper book publishing, which we are seeing today.
So nitrogen oxides out of my Jeep’s tailpipe are bad but the same thing in jet engine exhaust is good? I’ll just put a jet engine in my Jeep and help cool the planet.
You can write a lot of papers based on the various effects you observe in a climate model. The models are all wrong(*), so all of these papers are wrong as well, and all of the inmates in these institutions waste their talent and time and taxpayer’s money. Peer-reviewing each other, tapping each other on the back, giving advice to policymakers, all wrong. Hey, I observed a wiggle in the climate model, let’s tax shipping! today; let’s abolish flying! tomorrow. Hey, what about eating vegetables on mondays. What an insane cult.
(*)=because they did not predict anything correctly, obviously.
(*) I searched for the word “observations” in the text but somehow I missed it.
Why is it that when I read the words “model” and “climate” in a study, I immediately question its credibility?
I suspect this is all very negligible in the big picture, but the author is right about sulfur being nothing but a pollutant when burned at ground level. So remove it, if economical.
OT, and raging through Warmists email alerts:
Shock as retreat of Arctic sea ice releases deadly greenhouse gas
http://www.independent.co.uk/environment/climate-change/shock-as-retreat-of-arctic-sea-ice-releases-deadly-greenhouse-gas-6276134.html
Yeah. i know. It has been there for millions of years. It is near surface natural gas field.
“We find that only a third of the climate impact from aviation can be attributed to carbon dioxide.”
I find that a full 0/3 of climate can be attributed to aviation, and of that total, 100 per cent can be attributed directly to CO2, 50 per cent of which is offset by the cooling caused by sulfur.
If the net result is cooling, it sounds like the EU’s attempt to tax air travel CO2 is not only misguided but wrong as well. I propose we increase air travel by ten fold and take advantage of the cooling effect. Problem solved!
[Using multiple screen names violate site Policy. ~dbs, mod.]
M. Dacey says:
December 14, 2011 at 9:28 am
“Ironically, I can foresee a gradual decline in air travel as it is currently done to an “on-demand” model, where the plane doesn’t leave until the seats are filled, along with a simple decline based on fuel prices and a lessened need for business travel in an increasing age of “telepresence” and virtual networks.”
Air freight miles are exploding.
http://www1.eere.energy.gov/vehiclesandfuels/facts/2006_fcvt_fotw419.html
You will have to regulate that into oblivion; it doesn’t die voluntarily.
[Using multiple screen names violate site Policy. ~dbs, mod.]
If “desulfurization of jet fuel has a small, net cooling effect,” then by all means do not go to the expense of taking it out, because cooling is a far greater present danger than warming. Spending money to induce cooling is an obvious lose-lose.
“Particles of sulfate, formed by burning sulfur-laden jet fuel, act like tiny mirrors that scatter solar radiation back into space.” So, supposedly, another albedo effect upon the “climate”, although surely a tiny one. The truth is that the scattering of visible light, even by the thick clouds of Venus (as my Venus/Earth temperature comparison clearly shows), doesn’t affect the temperature outside of the clouds themselves, because the atmosphere is warmed by absorption of incident solar infrared, not by absorption of visible light (or infrared light, either) at the Earth’s surface. (Inside the clouds, the presence of liquid particles keeps the atmosphere about 5 degrees cooler than what it would otherwise be, probably simply because such particles have a larger specific heat than the air, thus they don’t warm quite as much as the air does, from the available heat.) This Harvard study is just more “greenhouse effect” modelling garbage, with upside-down atmospheric-warming physics assumed without question, so the truth is they just don’t have a clue what they are doing, thermodynamically. Not only is it pretend climate science, it is pretend basic physics. Since it accepts the consensus, of course, it easily gets published. My Venus/Earth comparison is the definitive, fundamental correction climate science needs–and it should have been done 20 years ago, even by students.
For geoengineering via stratospheric sulfur,
every jetliner would have sulfur to dump in the exhaust stream
(not burning through the engine as it does in fuel)
It’s turned on whenever the jet is above the tropopause.
The airlines would only charge a half the normal cargo price,
since it’s gone before the end of the flight.
I don’t want a cooler planet, I want a warmer planet. Right now its freezing outside, and we all know now that global freezing causes more global warming