Forward step in forecasting global warming

Aug 07, 2008

Arizona State University researchers have made a breakthrough in understanding the effect on climate change of a key component of urban pollution. The discovery could lead to more accurate forecasting of possible global-warming activity, say Peter Crozier and James Anderson.

Crozier is an associate professor in ASU's School of Materials, which is jointly administered by the College of Liberal Arts and Sciences and the Ira A. Fulton School of Engineering. Anderson is a senior research scientist in the engineering school's Department of Mechanical and Aerospace Engineering.

As a result of their studies of aerosols in the atmosphere, they assert that some measures used in atmospheric science are oversimplified and overlook important factors that relate to climatic warming and cooling.

The research findings are detailed in the Aug. 8 issue of Science magazine, in the article "Brown Carbon Spheres in East Asian Outflow and Their Optical Properties," co-authored by Crozier, Anderson and Duncan Alexander, a former postdoctoral fellow at ASU in the area of electron microscopy, and the paper's lead author.

So-called brown carbons – a nanoscale atmospheric aerosol species – are largely being ignored in broad-ranging climate computer models, Crozier and Anderson say.

Studies of the greenhouse effect that contribute directly to climate change have focused on carbon dioxide and other greenhouse gases. But there are other components in the atmosphere that can contribute to warming – or cooling – including carbonaceous and sulfate particles from combustion of fossil fuels and biomass, salts from oceans and dust from deserts. Brown carbons from combustion processes are the least understood of these aerosol components.

The parameter typically used to measure degrees of warming is radiative forcing, which is the difference in the incoming energy from sunlight and outgoing energy from heat and reflected sunlight. The variety of gasses and aerosols that compose the atmosphere will, under different conditions, lead to warming (positive radiative forcing) or cooling (negative radiative forcing).

The ASU researchers say the effect of brown carbon is complex because it both cools the Earth's surface and warms the atmosphere.

"Because of the large uncertainty we have in the radiative forcing of aerosols, there is a corresponding large uncertainty in the degree of radiative forcing overall," Crozier says. "This introduces a large uncertainty in the degree of warming predicted by climate change models."

A key to understanding the situation is the light-scattering and light-absorbing properties – called optical properties – of aerosols.

Crozier and Anderson are trying to directly measure the light-absorbing properties of carbonaceous aerosols, which are abundant in the atmosphere.

"If we know the optical properties and distribution of all the aerosols over the entire atmosphere, then we can produce climate change models that provide more accurate prediction," Anderson says.

Most of the techniques used to measure optical properties of aerosols involve shining a laser through columns of air.

"The problem with this approach is that it gives the average properties of all aerosol components, and at only a few wavelengths of light," Anderson says.

He and Crozier have instead used a novel technique based on a specialized type of electron microscope. This technique – monochromated electron energy-loss spectroscopy – can be used to directly determine the optical properties of individual brown carbon nanoparticles over the entire visible light spectrum as well as over the ultraviolet and infrared areas of the spectrum.

"We have used this approach to determine the complete optical properties of individual brown carbon nanoparticles sampled from above the Yellow Sea during a large international climate change experiment," Crozier says.

"This is the first time anyone has determined the complete optical properties of single nanoparticles from the atmosphere," Anderson says.

It's typical for climate modelers to approximate atmospheric carbon aerosols as either non-absorbing or strongly absorbing. "Our measurements show this approximation is too simple," Crozier says. "We show that many of the carbons in our sample have optical properties that are different from those usually assumed in climate models."

Adds Anderson: "When you hear about predictions of future warming or changes in precipitation globally, or in specific regions like the Southwestern United States, the predictions are based on computer model output that is ignoring brown carbon, so they are going to tend to be less accurate."

Source: Arizona State University

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Velanarris
3 / 5 (12) Aug 07, 2008
You'd think they'd focus on the actual causation of a warming climate.

Water vapor, 98% of which we are not culpable for.

Speaking of which, all of mankind's comtribution to the Carbon content in the atmosphere through fossil fuel consumption, industry, existence, anything we could possibly do to produce carbon totals up at a whopping 0.23% total yearly contribution.

Methane (far worse than carbon) even less.

The jig is up, lose the green guilt.
Glis
4.4 / 5 (7) Aug 07, 2008
Go Dr. Crozier! It's good that it's not just some prick (me) saying that models are too simple, and he backs it up with a real experiment. No offense to any climatologist, your field is brutal, but those of you that shower us with these far overreaching models make the rest of you look like clowns.

I'm glad good scientists are starting to keep the bad ones in check.
mikiwud
2.8 / 5 (9) Aug 07, 2008
Good job it's cooling!
When will these dickheads accept warming has stopped and research the effects of cooling?
The colder it gets and the bigger the population......
MikeB
3.2 / 5 (11) Aug 07, 2008
All very interesting. But as Velanarris said, we are ignoring the gorilla in the room... Water Vapor... Green is not cool anymore...
Soylent
3.5 / 5 (11) Aug 08, 2008
You'd think they'd focus on the actual causation of a warming climate.

Water vapor, 98% of which we are not culpable for.


If there were no greenhouse gases in the atmosphere at all, Earth would be an uninhabitable iceball.

Water vapour it a feedback, not a forcing. The amount of water vapour you can have in the atmosphere follows temperature; it is too short lived in the atmosphere to 'build up'. As such it cannot cause climate change; but it can amplify cooling or heating trends(positive feedback).

Climate change is not a problem if the rate of change is slow enough that infrastructructure is not obsoleted by climate change until after it has served its useful lifespan and if species have enough time to migrate and adapt to the changing climate without major extinctions. If the rate of change is too high it becomes problematic and you have to weigh the cost of mitigating climate change against the cost of adapting to climate change(including the cost of species extinctions, which usually won't be monetary).

Speaking of which, all of mankind's comtribution to the Carbon content in the atmosphere through fossil fuel consumption, industry, existence, anything we could possibly do to produce carbon totals up at a whopping 0.23% total yearly contribution.


Gross CO2 emissions don't matter. Vegetation decomposes, burns and respires, emitting enormous amounts of CO2; new vegetation takes its place, capturing an enormous amount of CO2. Averaged over a year the net effect fluctuates around zero, it's at or near equilibrium before you add human caused CO2-emissions.

The source of the atmospheric CO2 can be inferred from isotopic ratios(e.g. in carbon from tree rings which can be dated to a specific year based on the pattern of tree-ring thickness). It is human in origin.

Methane (far worse than carbon) even less.


Methane doesn't stay in the atmosphere for very long(it is eventually oxidized to CO2). At a given rate of emissions it tends to an equilibrium whereas CO2 does not.
RAL
3.9 / 5 (7) Aug 08, 2008
Unfortunately the entire field has been so polluted by politics its hard to tell who is hustling grants and who is doing research. Given the vast consensus we keep hearing about don't these folks feel somewhat embarassed about the fact that global temperatures haven't increased in nearly a decade"?

I'm all for research on global warming but it requires and enourmous dose of humility based on performance to date. The entire field seems one quarter step above snake oil research at best.
mikiwud
3 / 5 (8) Aug 08, 2008
Soylent,
CO2 has been less than now and 20 times more in the past,so how can you say it is in equilibrium?
CO2 levels are pretty constant all over the world.So take two examples.
1.warm day in England 80 deg F with 90% humidity,when the Sun goes down it stays very warm all night.
2.hot day in a desert 115 deg F with 5% humidity,when the Sun goes down the temperature drops straight away even to freezing.
The average temp could be higher in 1. than 2. cause only by water vapour.
I may be wrong in detail,but think about it and do a bit (more?) research.
Velanarris
3.5 / 5 (11) Aug 08, 2008

If there were no greenhouse gases in the atmosphere at all, Earth would be an uninhabitable iceball.
I don't debate this at all. I'm pretty sure most people understand the way the greenhouse affect both hurts and helps us, but here's the biggie. How do Greenhouses work?

Well, any gardener will tell you they hold heat in the environment inside the greenhouse, and they'll tell you that the key to doing so is maintaining a high relative humidity within the greenhouse. Humidity is a measure of, ta da, water vapor.

Water vapour it a feedback, not a forcing. The amount of water vapour you can have in the atmosphere follows temperature; it is too short lived in the atmosphere to 'build up'. As such it cannot cause climate change; but it can amplify cooling or heating trends(positive feedback).
Here's where you're going against common sense. Reading the article above, the "revolutionary" idea in this model is about measuring a molecule that acts as a prismatic magnifier for sun light.

I know another material in the atmosphere that does that. Typically you can tell when it's working over time due to the presence of a rainbow. We all know where those come from, sunlight passing through water vapor.

Climate change is not a problem if the rate of change is slow enough that infrastructructure is not obsoleted by climate change until after it has served its useful lifespan and if species have enough time to migrate and adapt to the changing climate without major extinctions. If the rate of change is too high it becomes problematic and you have to weigh the cost of mitigating climate change against the cost of adapting to climate change(including the cost of species extinctions, which usually won't be monetary).
Two things here. 1) what do you base your rate of change against? If you base it against the ranges of temperature found in the universe then the delta climate change on earth is miniscule. If you base it on temps required to support life, it's also very miniscule. If you base it on the temps in which human life can live comfortably then yes, the delta is huge. 2) It's always monetary to humans. We're not saving the environment because we're supposed to. We're saving the environment for financial gain, to stop others financial gain, to hamstring competing market places(US sanctions against China for polution, while the US refuses to sign the Kyoto Accord), to bring down industry bases that we ideologically disagree with (the destruction of the Pacific north west economy and livelyhood by dismantling the Lumber industry while we stand on more natural forrest resource in this country than we did when the US was inhabited by indigenous people).



Gross CO2 emissions don't matter. Vegetation decomposes, burns and respires, emitting enormous amounts of CO2; new vegetation takes its place, capturing an enormous amount of CO2. Averaged over a year the net effect fluctuates around zero, it's at or near equilibrium before you add human caused CO2-emissions.
Ok, well if the planet is causing global warming through natural process then how is curtailing our 0.28% contribution going to magically save the environment. It's not. It's going to kill people in third world countries, prevent innovations in the way we do business, and prevent the evolution of our societies.

The source of the atmospheric CO2 can be inferred from isotopic ratios(e.g. in carbon from tree rings which can be dated to a specific year based on the pattern of tree-ring thickness). It is human in origin.
You're going to have to point out a source on this one. Last I checked trees near volcanoes (#1 producer of atmosphere carbon) don't really stick around long enough to be examined.

Methane doesn't stay in the atmosphere for very long(it is eventually oxidized to CO2). At a given rate of emissions it tends to an equilibrium whereas CO2 does not.
Then why the crazy sanctions against the cattle industry in the Kyoto Accord? Did you ever read it? It'd surprise you what they went after.


As others said here: this is ridiculous.
NotParker
3.2 / 5 (9) Aug 08, 2008
What little warming has occurred in the last 30 years, has occurred in the Northern Hemisphere.

And that warming was caused by CLEANER AIR which allowed mure sunlight to reach the NH.

http://www.dailyt.../Europes Warming Attributed to Cleaner Air Not Climate Change/article12371.htm
Velanarris
3.4 / 5 (10) Aug 08, 2008
if the people knocking valid global warming research truly see a flaw in the hypothesis, implement experiments, build models, write papers and get them published in peer reviewed articles, otherwise, shut the fuck up.


If the people in the gloabal warming movement practiced what they preach (Al Gore's new house boat), or read the conflicting arguments rather than creating hotbed topic research to receive grant money, then perhaps people like the above quoted wouldn't be so outraged over their intellectual mistreatment.
RAL
3 / 5 (8) Aug 08, 2008
"..if the people knocking valid global warming research truly see a flaw in the hypothesis, implement experiments, build models, write papers and get them published in peer reviewed articles, otherwise, shut the fuck up. "

Yeah, until you have personally done as much research and published as many scholarly papers in peer reviewed journals as Al Gore has you "deniers" are not entitled to have an opinion!

You tell 'em gmurphy. Until they do the research, they have no right to criticize imminent workers in the field like Sheryl Crow and John Travolta.

Hmm, I sense a one sided rule here eh? Only dissenters need be credentialed.
Modernmystic
4.2 / 5 (5) Aug 09, 2008
Wow...very, VERY well said RAL.
MikeB
4.2 / 5 (5) Aug 10, 2008
Before the IPCC released the last report on Global warming, they ran it by Barbra Streisand just to make sure it was "perfect".
EarthScientist
3 / 5 (3) Aug 11, 2008
You go boys, you tell em!!
Global warming is cyclical,as us grid scientists know, but some would say we "Blow" only cuz they have a flip in their show .Those Arizona folks need to get out of the sun,their underwear is showing.

The global warming will stop,as soon as the orbital processes deplete,just as before,they learned to make their goofy models,and sniff the Testors.

GrayMouser
not rated yet Sep 07, 2008
Yeah, until you have personally done as much research and published as many scholarly papers in peer reviewed journals as Al Gore has you "deniers" are not entitled to have an opinion!


Al Gore has published in a peer reviewed journal??? Which one? Why isn't there a URL? What date was it published? April 1st?
GrayMouser
not rated yet Sep 07, 2008
if the people knocking valid global warming research truly see a flaw in the hypothesis, implement experiments, build models, write papers and get them published in peer reviewed articles, otherwise, shut the fuck up.


Interesting sequence of steps...
1) Hypothesis.
2) Experiment.
3) Models.
4) Papers

I would switch 2&3 simply because the model may tell you what you need to look for in your experiments. Then the experiments confirm or dispute the model.

Strange how the AGW folks went from models to papers without the experiments. Oh well, it's not important.