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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mondo says:
“December 14, 2011 at 7:38 am
Willis,
A very interesting question to ask the oil majors (BP for example) is “the concept of ‘Reserves’ is an economic concept, meaning that portion of ‘Resources’ that can be economically extracted at a particular oil price”
I like to tease the Peak Oil mob with the simple question as to why there was only 25 years of reserves in 1945; by 1970, that oil was gone, but we had 30 years of reserves; by 2000, all the 1970′s oil had gone but we had 40 years of reserves. How come? They keep telling me we are about to hit a peak – they clearly don’t even understand the question.
The answer, of course, is that in 1945 we were talking oil at $2/bbl; by 1970 there was no more $2/bbl oil but lots of $10/bbl; by 2000 there was no more $10/bbl oil but lots of $25 oil. Yes, ‘reserves’ are indeed an economic concept. But will the Peak Oil gloomsters understand that simple economics? I haven’t yet found one.”
____________________________________________________________________________
Hi,
There is a department of “EXPLORATION” at Every Oil Company. It is clear that this department could have not been able to “EXPLORE” all the oil fields from the very beginning.
They do not stay silent too, to end one “reserve” for whatever years and then start another stage for another series of years . Prices also, cannot be fixed for Y.E.A.R.S, the mechanism of MARKET is the ruler. BP and the others are not so wise to forecast the oil index for the next 100 years, just they know there would be inflation and too many other reasons… political..etc to affect the rates. Yes if we let the scientists to predict the OIL prices, oh god!, we may have something, of course we utterly cannot rely on.
When, oh when will those smart-alecky, money-grubbing and arrogant wannabe-$cientists learn to leave their fingers off the planet?
Nature is doing well in every way, all alone, even without those pointless and clueless do-gooders!
“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.”
========
Really, important, fastest growing, no alternative, many circumstances, better understand, fossil fuel-burning sector, what it’s doing to climate.
Is this the best that Yale writers can do ?
If so, they stand no chance against the writers at WUWT.
ThePowerofX says:
December 14, 2011 at 9:50 am
Because you have been indoctrinated into believing all climate models are useless.
=======
Didn’t take no Doctor, to convince me the climate models are useless.
It’s nothing of the sort. The “test bed for green fuels” is smoke and mirrors that allows people to get past the notion that one of Obama”s transition team members, major “bundler” of campaign donations, and the person that consulted on the energy portion of the stimulus bill has a rather large stake in the company selling the fuel to the Navy.
It is, again, about money.
http://hotair.com/archives/2011/12/11/navy-buys-biofuel-for-16-a-gallon/
So here we have a person developing the policy and then cashing in on the implementation of that policy — sort if like UEA with CRU and Tyndall at either end of the global warming money cycle.
So, the real “Control Knob” for global climate has been found. Just fiddle with airliners’ fuel mix.
Warmer? Cooler? Where, how much, and how fast, sir? No problem!
Brian H says:
December 14, 2011 at 4:40 pm
So, the real “Control Knob” for global climate has been found. Just fiddle with airliners’ fuel mix.
Warmer? Cooler? Where, how much, and how fast, sir? No problem!
=======
Very good point.
They know nothing about economics, only how to feed upon those that produce.
Look at our deficit, neither party can afford to lose the votes/promises they made to get elected, nor can we pay for their promises made.
So, now what ?
Hmmm. The article said that jet exhaust will still have a small net cooling effect on climate with the sulfur removed. This is a preemptive defense of low sulfur fuel, avoiding the obvious conclusion that the current jet exhaust with sulfur has a significant cooling effect on the atmosphere.
While I’m not about to pay $25 to read their paper, I would bet they don’t have any jet engine emission data to show the formation of nitrates. Combustion engines mostly produce NO at the exhaust. The NO subsequently reacts in sunlight to produce NO2. Now NO2 can react in sunlight with hydrocarbons to produce ozone and other nasty organic compounds; but nitrates, I’m not so sure.
Thus, I question their basic premise that any appreciable amount of nitrates are formed.
Okay. Before some atmospheric chemist jumps all over me. Yes, NO2 can react with volatile organic compounds to form peroxyacyl nitrate (PaN). It’s formation is very dependent on the amount of volatile organic compounds available. PaN has long been identified as a component of Los Angles smog.
Well they took the sulfur out of diesel fuel and turn it from one of the cheapest fuels to more expensive than gasoline, so expect airline tickets to triple in price and no one will get to fly anymore….
Watts Up With That: “Aircraft exhaust particles lodge in lungs & cause respiratory & cardiovascular illness.”
Yep, so just call it what it is.
The picture showing ‘contrails’ is not relevant since these are ice crystals from the water produced by burning the fuel.
Removing S from jet fuel will lead to more engine failures due to lack of lubrication needed in the engine fuel system which the Sulphur provides at little to no cost.
Translation: Somebody along the line is anticipating making piles of $$$. They probably have a new patent pending with a ‘miracle’ lubricant to replace the sulphur in jet fuels. The claim of saving the Climate is nothing more than a flimsy excuse at a sales gimmick.
@TimO – It was coincidence that the diesel fuel skyrocketed around that time. It has more to do with increased demand for diesel relative to supply. The cost of increased desulfurization is only about $0.05-$0.10/gallon. Refineries are designed to operate with certain types of crude and within certain fuel spec ranges. When refineries had to start shifting their production, they started shifting into the more expensive range for diesel production, thus they needed to charge higher prices.
Ugh. I’m sick of jet contrails. They have gotten so bad these past 10-15 years. I live in rural America and the contrails often mark up the entire sky. It’s just ugly. Often the haze lasts all day and makes my evening sit out on the deck that much less enjoyable. Venus and the setting sun, and contrail blitzkrieg. They need to do something to make LESS contrails! LESS haze! LESS ugly mess in the beautiful sky. I’m an old country boy and this is just getting out of hand. Maybe Iran will close the straight of Hormuz and the price of oil will sky-rocket – and people will quit flying. I don’t fly. But I have to sit and look at the ugly mess above my rooftop, on my daily drive to work, on my daily walks. Ugly.
[snip. Chemtrail discussions verboten. ~dbs, mod.]
Dunno why Anthony would cotton on to his mods posting that word if it’s verboten.
Its based on another model,watch it chaps, may come back and bite.
I haven’t had time to (re)read this yet, but I think this is the report I was seeking, reflecting work done in the late 1970s at the Univ. of Illinois, which shows, if I recall correctly, that contrails reduced or attenuated the amount of sunlight reaching the ground. Who knew?
(Cherrypicked from Conclusion and Discussion, page 92)
http://www.isws.illinois.edu/pubdoc/CR/ISWSCR-298.pdf
And in a related matter:
AirTran to charge overweight passengers for two seats
http://thehill.com/blogs/transportation-report/aviation/188591-airtran-to-adopt-southwest-airlines-customers-of-size-policy
Finally, I’m sticking with my original conjecture:
It is not difficult to convince portly people that It’s Too Darn Hot! Since the increasing sensation of warmth has nothing to do with one’s own increasing girth, it must be Global Warming!
87)
-sp
Doesn’t the sulfur emitted by volcanoes cause cooling? I’m confused.
[If] removing the sulfur really has that effect, they may be onto something.