There's a new paper out in Nature, by Daniel Feldman and his colleagues, in which they describe how they've measured the contribution of CO2 to radiative forcing at the surface. The measurements were taken in Alaska and Oklahoma. This is not something that's easy to do. It is not straightforward. There are lots of things that happen in the lower atmosphere and at the surface. The scientists managed to extract the signal of radiative forcing from CO2 from that of other things that affect spectral measurements.
The video below from the Lawrence Berkeley National Laboratory plots the radiative CO2 forcing at the surface (orange) and the atmospheric concentration of CO2 (blue):
These graphs show carbon dioxide’s increasing greenhouse effect at two locations on the Earth’s surface. The first graph shows CO2 radiative forcing measurements obtained at a research facility in Oklahoma. As the atmospheric concentration of CO2 (blue) increased from 2000 to the end of 2010, so did surface radiative forcing due to CO2 (orange), and both quantities have upward trends. This means the Earth absorbed more energy from solar radiation than it emitted as heat back to space. The seasonal fluctuations are caused by plant-based photosynthetic activity. The second graph shows similar upward trends at a research facility on the North Slope of Alaska. (Credit: Berkeley Lab)
The paper is described in a press release at Berkeley Lab, which states in part:
The influence of atmospheric CO2 on the balance between incoming energy from the Sun and outgoing heat from Earth (also called the planet's energy balance) is well established. But this effect has not been experimentally confirmed outside the laboratory until now. The research is reported Feb. 25 in the advance online publication of the journal Nature.
The results agree with theoretical predictions of the greenhouse effect due to human activity. The research also provides further confirmation that the calculations used in today's climate models are on track when it comes to representing the impact of CO2.
The scientists measured atmospheric carbon dioxide's contribution to radiative forcing at two sites, one in Oklahoma and one on the North Slope of Alaska, from 2000 to the end of 2010. Radiative forcing is a measure of how much the planet's energy balance is perturbed by atmospheric changes. Positive radiative forcing occurs when Earth absorbs more energy from solar radiation than it emits as thermal radiation back to space. It can be measured at Earth's surface or high in the atmosphere. In this research, the scientists focused on the surface.
They found that CO2 was responsible for a significant uptick in radiative forcing at both locations, about two-tenths of a Watt per square meter per decade. They linked this trend to the 22 parts-per-million increase in atmospheric CO2 between 2000 and 2010. Much of this CO2 is from the burning of fossil fuels, according to a modeling system that tracks CO2 sources around the world.
"We see, for the first time in the field, the amplification of the greenhouse effect because there's more CO2 in the atmosphere to absorb what the Earth emits in response to incoming solar radiation," says Daniel Feldman, a scientist in Berkeley Lab's Earth Sciences Division and lead author of the Nature paper.
"Numerous studies show rising atmospheric CO2 concentrations, but our study provides the critical link between those concentrations and the addition of energy to the system, or the greenhouse effect," Feldman adds.
You can read the full press release here at Berkeley Lab.
What the research does is show that what is expected is what is happening. Adding CO2 to the air means that less energy escapes to space and more is reflected back to the surface. That radiative forcing has now been measured at the surface.
The paper itself provides all the technical details. It describes how the observations were made and how they were interpreted. It wasn't a simple matter of reading a meter. There are lots of things to take into account. Here is some of what the authors say:
We focus here on clear-sky flux changes because models predict most of the CO2 surface forcing to occur under clear-sky conditions.
Specialized atmospheric observations at experimental sites in the mid-latitude continental Southern Great Plains (SGP) and the Arctic marine North Slope of Alaska (NSA) sites by the US Department of Energy Atmospheric Radiation Measurement (ARM) programme produce the integrated data sets required for an independent diagnosis of the surface radiative effects of CO2. We used spectroscopic measurements from the Atmospheric Emitted Radiance Interferometer (AERI) instrument and atmospheric state data at these two sites to test whether the impact of rising CO2 on downwelling longwave radiation can be rigorously detected. By basing this analysis on sets of independent measurements at high temporal frequency over long duration, we empirically established how anthropogenic emissions, mediated by variations in photosynthetic activity and respiration, are altering the Earth’s surface energy balance.
However, AERI spectral measurements and trends are sensitive to many different components of the atmospheric state. To interpret these measurements and attribute specific signals to rising CO2 requires an accurate radiative-transfer model that reproduces these spectra on the basis of an independent assessment of the state of the atmosphere. The model must capture instantaneous signals and long-term trends in the spectra to determine the effects of CO2 on diurnal to decadal timescales.
We used the Line-by-Line Radiative Transfer Model (LBLRTM)18, which is continuously compared against other line-by-line models4 and observations...
Anthony Watts pretends to know stuff
Anthony Watts wrote a few words about it in his intro to his copy and paste. He said:
From the “this ought to shut up the “Skydragon slayers” department. Despite sophomoric claims that I’m a “denier”, I’ve never disputed that CO2 has a role in warming via retardation of IR transfer from the surface to the top of the atmosphere. What is really the issue related to AGW claims are the posited/modeled but not observed feedbacks and the logarithmic (not linear) saturation curve response of CO2. Along those lines, eyeballing the graph presented from the north slope of Alaska, it appears there might be a bit of a slowdown or “pause” in the rate of forcing from about 2007 onward. Hopefully, LBL will release the data for independent analysis.
Did you spot his "eyeballing"?.
As well as that he talks about what "is really the issue" - his "posited/modeled but not observed feedbacks". Goodness only knows what he's referring to there. And let's guess how he knew that CO2 has a log relationship with surface temperature? It would have been either directly or indirectly from climate scientists.
Finally, you'll notice his little conspiratorial dig in the last sentence - about releasing the data for independent analysis. He's not suggesting that he do any independent analysis - I doubt he'd be capable. That comment of his confirms (again) that he never bothers to read the papers that the press releases he copies are about. He rarely links to the paper (and didn't this time) - and he didn't even visit the website, I'd say. The methodology and data are referenced in the paper and there is also a heap of material provided as extended data figures and tables.
From the WUWT comments
Although I haven't seen anyone at WUWT attack their host Anthony Watts for agreeing that the greenhouse effect is real, there were lots and lots of comments that disputed it. Here's a sample of comments:
Janice Moore was the first to comment. She is a holier than thou denier (and the resident God botherer at WUWT)
February 25, 2015 at 11:20 am
“They attributed this upward trend to rising CO2 levels from fossil fuel emissions.”
With absolutely NO proof of causation.
Janice subsequently quoted Murry Salby - who can best be described as a failed climate scientist whose pronouncements suggest that he doesn't believe that burning hydrocarbons releases CO2.
CodeTech doesn't believe the greenhouse effect is possible. He's an all-or-nothing chap and a conspiracy nutter.
February 25, 2015 at 11:32 am
Meanwhile, back in reality, if it was even possible for CO2 levels to create temperature havoc, it would have already happened. Since the planet is still here, it’s only pseudo-science.
Simple convection effects completely swamp any tiny radiative changes, and that doesn’t require decades of data fiddling, name calling, bad science, government grants, increased taxes, etc.Here's some of what throwing waste CO2 into the air has caused so far - a big rise in the mean global surface temperature:
whiten replies to codetech that an increase in radiative forcing won't necessarily cause the planet to heat up. I don't know what he thinks radiative forcing is.
February 25, 2015 at 4:23 pm
Meanwhile, back in reality, if it was even possible for CO2 levels to create temperature havoc.
This new thing here does not prove that CO2 emissions cause climate change or as you put it, temperature havoc………, it simply proves that CO2 emissions increase RF (Radiative Forcing).
Bubba Cow's protest is that correlation doesn't mean causation. Except in this case there is causation.
February 25, 2015 at 4:44 pm
actually they have, at least here, shown in graphs that behaviors of CO2 and radiative forcing eyeball similar “trends”. They don’t provide the data or the stats – say correlations – to estimate any relationship and,even if they did or do in the paper, that wouldn’t prove anything.
CodeTech has second thoughts, and decides he doesn't want to be taken for a complete nincompoop. An incomplete nincompoop is okay with him, though. One who can spell big words like "preponderance" - and might even know what it means.
February 25, 2015 at 7:39 pm
Exactly what scarletmacaw said.
NOBODY (that I know of) has ever said that CO2 has absolutely NO effect, just that the effect it has is inconsequential. And that is something that neither you nor anyone else CAN EVER SHOW.
The preponderance of evidence is that we should not be worrying about CO2, not even a little, at the levels we’re dealing with.
rh, like Anthony Watts and a few other WUWT-ers, say they hope for data and methodology. None of them can be bothered getting it from the paper and extended data figures and tables, Asking for it is enough for them, with the implication that the scientists might try to hide it (in plain sight). Wanting wondering Willis to play with the data is pretty hilarious.
February 25, 2015 at 11:38 am
It looks like the two curves are diverging at about the same rate as all of the model vs. reality graphs. Maybe it’s “the logarithmic (not linear) saturation curve response of CO2″, or maybe it’s the increasing rate of growth of plants now that they are less CO2 deprived. Hopefully they release their data and methodology. I’d like to see it get the Eisenbach treatment before buying in.
A C Osborn is one very mixed up little denier. He confuses the Lawrence Berkeley National Laboratory with the Berkeley Earth project. He wants "Error Bars" - when of course the paper discusses the uncertainty limits. And if he couldn't see the paper itself, the abstract does as well. "The time series both show statistically significant trends of 0.2 W m−2 per decade (with respective uncertainties of ±0.06 W m−2 per decade and ±0.07 W m−2 per decade) and have seasonal ranges of 0.1–0.2 W m−2." Since Anthony Watts didn't link to the paper, I suppose you can't expect his readers to try to find it.
February 25, 2015 at 11:46 am
So, these measurements are only taken at night then?
So where are the links to the data, has it been properly Peer Reviewed?
Why does it need “The scientists used the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility located at Berkeley Lab, to conduct some of the research.”
to do this research.
After seeing what BEST does to surface temperature records I would not trust anything that comes out the the place.
And then there is this “They can detect the unique spectral signature of infrared energy from CO2.”
With what accuracy I wonder?
So that is the one tiny little band where it is not swamped by H2O then.
As someone else said what were the Error Bars on the 0.2 W/m^2?
Mr. Pettersen tries to explain what sky dragon slayers "believe". I think that's what he's doing.
February 25, 2015 at 1:02 pm
Why should any Dragonslayer care about this? Nobody denies ir radiation. Its the automatic asumption that this ir will be convertet to heat at the bottom of the atmosphere the slayers dont accept.
Anyhow an increase in co2 will not generate heat simply because co2 radiates in any direction and every co2 molecule will have at least 6 directions to radiate where at least 5 of them will not be back to earths surface!
AndyG55 is just another denier protesting science, typical of the illiterati at WUWT.
February 26, 2015 at 12:58 am
Notice that the so-called “forcing” does not match the RSS/UAH temperatures values.
Natural variation FAR FAR out-weighs ANY pseudo-warming effect of CO2
The article got a lot more comments than usual at WUWT. At the time of the original archiving there were 289 "thoughts", and now it's up to 314 "thoughts". My reaction to the comments? What a dumb bunch of people Anthony Watts has as "fans". Most of them are still stuck in the "CO2 doesn't cause warming" mode. Nutters, the lot of them.
D. R. Feldman, W. D. Collins, P. J. Gero, M. S. Torn, E. J. Mlawer, T. R. Shippert. Observational determination of surface radiative forcing by CO2 from 2000 to 2010. Nature, 2015; DOI: 10.1038/nature14240