September 26, 2012

More Evidence Against a Methane Time Bomb

Over at Watts Up With That, Anthony Watts has highlighted a recent press release from the German Helmholtz Center for Ocean Research Kiel announcing the preliminary findings from an expedition this summer to the Greenland Sea (off the coast of Spitzbergen). The expedition on the German research vessel the Maria S. Merian was aimed at investigating the release of methane from the seafloor—one of the many potential apocalyptic positive feedback pathways which lead from an initial warming instigated by anthropogenic greenhouse gas emissions. Watts drew attention to the press release because the researchers were reporting that contrary to expectations, the release of methane from the seabed was found not to be a recent phenomenon (i.e., a result of global warming), but instead that many of the gas outlets had been active for long before local ocean temperatures have been rising.

According to the press release:

Above all the fear that the gas emanation is a consequence of the current rising sea temperature does not seem to apply.

And also, although the full details from the expedition’s data collections will not be known for several months, the scientists suggested that

[T]he observed gas emanations are probably not caused by human influence.

(more…)




June 7, 2012

Asian Air Pollution Warms U.S. More Than U.S. Greenhouse Gas Emissions?

There is a just-published study that provides evidence that air pollution emanating from Asia will warm the U.S. as much as or even more than all U.S. greenhouse gas (GHG) emissions.

Such a result effectively renders all EPA and other efforts at mitigating climate change in the U.S. by limiting homegrown GHG emissions mute.

Over at the web site Master Resource, there is a detailed discussion into how the warming effect from Asian air pollution compares with the warming effect of U.S. CO2 emissions. [Spoiler Alert] It turns out, that the two are pretty much on par with one another—which leads to the uncomfortable question: If the future temperature rise in the U.S. is subject to the whims of Asian environmental and energy policy, then what sense does it make for Americans to have their energy choices regulated by efforts aimed at mitigating future temperature increases across the US—efforts which may have less of an impact on temperatures than the policies enacted across Asia?

(more…)




February 27, 2012

Bigfoot, the Loch Ness Monster, and High Climate Sensitivity

A few months ago, we reported on a paper in the scientific literature (Schmittner et al. 2011) that concluded that there were only “vanishing probabilities” that the value of the earth’s climate sensitivity—the amount of global temperature change resulting from a doubling of the atmospheric carbon dioxide content—was above 3.2°C, and that a climate sensitivity exceeding 6°C was “implausible.” Now, a new paper has been published (Olson et al., 2012) that finds that the 95% confidence range for the value of the earth’s actual climate sensitivity extends only to a value as great as 4.9°C. This is yet another in an expanding list of papers that strongly suggest that that the IPCC entertainment of the possibility that the earth’s climate sensitivity is extremely high (say, greater than 5-6°C, is wrong).

As apocalyptic climate change lurks among high sensitivity values, these new findings virtually eliminate the places where it could be hiding—and relegate talk of apocalyptic climate change to that of Loch Ness monsters, big foot, and woolly mammoths in Siberia.

(more…)




February 8, 2012

“A significant measure of negative feedback to global warming”

Filed under: Climate Forcings

A new paper just published in Geophysical Research Letters by Roger Davies and Mathew Molloy of the University of Auckland finds that over the past decade the global average effective cloud height has declined and that “If sustained, such a decrease would indicate a significant measure of negative cloud feedback to global warming.”

Davies and Molloy are quick to point out that part of the decline from 2000 to 2010 in cloud height is due to the timing and variability of El Niño/La Niña events over the same period, however, there still seems to be evidence that at least part of the decline may remain even when El Niño/La Niña variability is accounted for.

Figure 1 shows the history of the effective cloud height, as determined by Davies and Molloy from satellite observations, from March 2000 through February 2010. The dotted line is the linear trend through the data as determined by Davies and Molloy and has a value of -44 meters per decade (+/- 22m). However, clearly the trend is influenced by the large negative departure centered around the beginning of 2008 that was related to a moderate La Niña event in the Pacific Ocean. To avoid the influence of the this event, Davies and Molloy calculate the difference between the cloud heights during the first and last years of their record and still find a decline of 31 m/dec (+/- 11m). Although this latter technique doesn’t fully account for the El Niño/La Niña signal in the record, it does at least give some indication of the influence of the large negative departures in the latter half of the record, and indicates that the overall decline is not simply an artifact of a single event.


Figure 1. Deseasonalized anomalies of global effective cloud-top height from the 10-year mean. Solid line: 12-month running mean of 10-day anomalies. Dotted line: linear regression. Gray error bars indicate the sampling error (±8 m) in the annual average (source: Davies and Molloy, 2012).

(more…)




February 6, 2012

The Sun: O Inconstant Star!

Filed under: Climate Forcings, Solar

As solar activity declines and rate of global warming follows suit, it is natural to wonder whether the two are in some manner related.

Science is all over the map on this one—and is hardly the “settled” stuff our greener friends want us to believe. One school holds that there is little-to-no detectable relationship between solar changes and surface temperatures, while another holds that there is a strong influence and that a projected period of low solar activity over the next several decades will offset much of the anthropogenic greenhouse-gas induced warming. Of course, there are also gradations in between these poles of opinion.

(more…)




January 10, 2012

Will Replicated Global Warming Science Make Mann Go Ape?

About 10 years ago, December 20, 2002 to be exact, we published a paper titled “Revised 21st century temperature projections” in the journal Climate Research. We concluded:

Temperature projections for the 21st century made in the Third Assessment Report (TAR) of the United Nations Intergovernmental Panel on Climate Change (IPCC) indicate a rise of 1.4 to 5.8°C for 1990–2100. However, several independent lines of evidence suggest that the projections at the upper end of this range are not well supported…. The constancy of these somewhat independent results encourages us to conclude that 21st century warming will be modest and near the low end of the IPCC TAR projections.

We examined several different avenues of determining the likely amount of global warming to come over the 21st century. One was an adjustment to climate models based on (then) new research appearing in the peer-reviewed journals that related to the strength of the carbon cycle feedbacks (less than previously determined), the warming effect of black carbon aerosols (greater than previously determined), and the magnitude of the climate sensitivity (lower than previous estimates). Another was an adjustment (downward) to the rate of the future build-up of atmospheric carbon dioxide that was guided by the character of the observed atmospheric CO2 increase (which had flattened out during the previous 25 years). And our third estimate of future warming was the most comprehensive, as it used the observed character of global temperature increase—an integrator of all processes acting upon it—to guide an adjustment to the temperature projections produced by a collection of climate models. All three avenues that we pursued led to somewhat similar estimates for the end-of- the-century temperature rise. Here is how we described our findings in paper’s Abstract:

Since the publication of the TAR, several findings have appeared in the scientific literature that challenge many of the assumptions that generated the TAR temperature range. Incorporating new findings on the radiative forcing of black carbon (BC) aerosols, the magnitude of the climate sensitivity, and the strength of the climate/carbon cycle feedbacks into a simple upwelling diffusion/energy balance model similar to the one that was used in the TAR, we find that the range of projected warming for the 1990–2100 period is reduced to 1.1–2.8°C. When we adjust the TAR emissions scenarios to include an atmospheric CO2 pathway that is based upon observed CO2 increases during the past 25 yr, we find a warming range of 1.5–2.6°C prior to the adjustments for the new findings. Factoring in these findings along with the adjusted CO2 pathway reduces the range to 1.0–1.6°C. And thirdly, a simple empirical adjustment to the average of a large family of models, based upon observed changes in temperature, yields a warming range of 1.3–3.0°C, with a central value of 1.9°C.

We thus concluded:

Our adjustments of the projected temperature trends for the 21st century all produce warming trends that cluster in the lower portion of the IPCC TAR range. Together, they result in a range of warming from 1990 to 2100 of 1.0 to 3.0°C, with a central value that averages 1.8°C across our analyses.

Little did we know at the time, but behind the scenes, our paper, the review process that resulted in its publication, the editor in charge of our submission, and the journal itself, were being derided by the sleazy crowd that revealed themselves in the notorious “Climategate” emails, first released in November, 2009. In fact, the publication of our paper was to serve as one of the central pillars that this goon squad used to attack on the integrity of the journal Climate Research and one of its editors, Chris de Freitas.

The initial complaint about our paper was raised back in 2003 shortly after its publication by Tom Wigley, of the US National Center for Atmospheric Research and University of Toronto’s L. D. Danny Harvey, who served as supposedly “anonymous” reviewers of the paper and who apparently had a less than favorable opinion about our work that they weren’t shy about spreading around. According to Australian climate scientist Barrie Pittock:

I heard second hand that Tom Wigley was very annoyed about a paper which gave very low projections of future warmings (I forget which paper, but it was in a recent issue [of Climate Research]) got through despite strong criticism from him as a reviewer.

So much for being anonymous.

The nature of Wigley and Harvey’s dissatisfaction was later made clear in a letter they sent to Chris de Freitas (the editor at Climate Research who oversaw our submission) and demanded to know the details of the review process that led to the publication of our paper over their recommendation for its rejection. Here is an excerpt from that letter:

Your decision that a paper judged totally unacceptable for publication should not require re-review is unprecedented in our experience. We therefore request that you forward to us copies of the authors responses to our criticisms, together with: (1) your reason for not sending these responses or the revised manuscript to us; (2) an explanation for your judgment that the revised paper should be published in the absence of our re-review; and (3) your reason for failing to follow accepted editorial procedures.

Wigley asked Harvey to distribute a copy of their letter of inquiry/complaint to a large number of individuals who were organizing some type of punitive action against Climate Research for publishing what they considered to be “bad” papers. Apparently, Dr. de Freitas responded to Wigley and Harvey’s demands with the following perfectly reasonable explanation:

The [Michaels et al. manuscript] was reviewed initially by five referees. … The other three referees, all reputable atmospheric scientists, agreed it should be published subject to minor revision. Even then I used a sixth person to help me decide. I took his advice and that of the three other referees and sent the [manuscript] back for revision. It was later accepted for publication. The refereeing process was more rigorous than usual.

This did little to appease to those wanting to discredit Climate Research (and prevent the publication of “skeptic” research) as evidenced by this email from Mike Mann to Tom Wigley and a long list of other influential climate scientists:

Dear Tom et al,

Thanks for comments–I see we’ve built up an impressive distribution list here!

Much like a server which has been compromised as a launching point for computer viruses, I fear that “Climate Research” has become a hopelessly compromised vehicle in the skeptics’ (can we find a better word?) disinformation campaign, and some of the discussion that I’ve seen (e.g. a potential threat of mass resignation among the legitimate members of the CR editorial board) seems, in my opinion, to have some potential merit.

This should be justified not on the basis of the publication of science we may not like of course, but based on the evidence (e.g. as provided by Tom and Danny Harvey and I’m sure there is much more) that a legitimate peer-review process has not been followed by at least one particular editor.

Mann went on to add “it was easy to make sure that the worst papers, perhaps including certain ones Tom refers to, didn’t see the light of the day at J. Climate.” This was because Mann was serving as an editor of the Journal of Climate and was indicating that he could control the content of accepted papers. But since Climate Research was beyond their direct control, it required a different route to content control. Thus pressure was brought to bear on the editors as well as on the publisher of the journal. And, they were willing to make things personal. For a more complete telling of the type and timeline of the pressure brought upon Chris de Freitas and Climate Research see this story put together from the Climategate emails by Anthony Watts over at Watts Up With That.

Now, let’s turn the wheels of time ahead 10 years, to January 10, 2012. Just published in the journal Geophysical Research Letters is a paper with this provocative title: “Improved constraints in 21st century warming derived using 160 years of temperature observations” by Nathan Gillett and colleagues from the Canadian Centre for Climate Modelling and Analysis of Environment Canada (not a group that anyone would confuse with the usual skeptics). An excerpt from the paper’s abstract provides the gist of the analysis:

Projections of 21st century warming may be derived by using regression-based methods to scale a model’s projected warming up or down according to whether it under- or over-predicts the response to anthropogenic forcings over the historical period. Here we apply such a method using near surface air temperature observations over the 1851–2010 period, historical simulations of the response to changing greenhouse gases, aerosols and natural forcings, and simulations of future climate change under the Representative Concentration Pathways from the second generation Canadian Earth System Model (CanESM2).

Or, to put it another way, Gillett et al. used the observed character of global temperature increase—an integrator of all processes acting upon it—to guide an adjustment to the temperature projections produced by a climate model. Sounds familiar!!

And what did they find? From the Abstract of Gillett et al.:

Our analysis also leads to a relatively low and tightly-constrained estimate of Transient Climate Response of 1.3–1.8°C, and relatively low projections of 21st-century warming under the Representative Concentration Pathways.

The Transient Climate Response is the temperature rise at the time of the doubling of the atmospheric CO2 concentration, which will most likely occur sometime in the latter decades of this century. Which means that results of Gillett et al. are in direct accordance with the results of Michaels et al. published 10 years prior and which played a central role in precipitating the wrath of the Climategate scientists upon us, Chris de Freitas and Climate Research.

Both the Gillett et al. (2012) and the Michaels et al. (2002) studies show that climate models are over-predicting the amount of warming that is a result of human changes to the constituents of the atmosphere, and that when they are constrained to conform to actual observations of the earth’s temperature progression, the models project much less future warming (Figure 1).


Figure 1. Dashed lines show the projected course of 21st century global temperature rise as projected by the latest version (CanESM2) of the Canadian coupled ocean‐atmosphere climate model for three different future emission scenarios (RCPs). Colored bars represent the range of model projections when constrained by past 160 years of observations. All uncertainty ranges are 5–95%. (figure adapted from Gillet et al., 2012: note the original figure included additional data not relevant to this discussion).

And a final word of advice to whoever was the editor at GRL that was responsible for overseeing the Gillett et al. publication—watch your back.

References:

Gillett, N.P., et al., 2012. Improved constraints on 21st-century warming derived using 160 years of temperature observations. Geophysical Research Letters, 39, L01704, doi:10.1029/2011GL050226.

Michaels, P.J., et al., 2002. Revised 21st century temperature projections. Climate Research, 23, 1-9.

[01/11/12: This post has been updated to correct the spelling of Gillett.]




December 16, 2011

“Methane Time Bomb in Arctic Seas – Apocalypse Not”

Our headline is taken from New York Times blogger Andy Revkin’s recent DotEarth post covering the results of a new paper which investigates the relationship between higher temperatures in recent decades and methane release from the Arctic seabed off the Siberian coast. As you can probably tell from the headline, the research team, led by Igor Dmitrenko, did not find that global warming, current and future, was going to have much of a dramatic impact on the release of methane from the Arctic seas. This is a fairly significant finding because methane—which has about 20 times the impact on the greenhouse effect that carbon dioxide does on a molecule by molecule basis—has the potential to act as a large amplifier (positive feedback) to a warming climate. Consequently the specter of a large Arctic methane release plays a prominent role in many of the more alarming future climate change storylines.

(more…)




December 5, 2011

Huh? A Reply to Nathan Urban

Filed under: Climate Forcings

A few weeks ago, we ran a story about a paper which was (then) soon to be published in Science magazine which generally concluded that the earth’s climate sensitivity (how much the earth’s average temperature will rise from a doubling of the atmospheric carbon dioxide concentration) was likely lower than the IPCC’s best guess (which is 3°C) and known with far less uncertainty—especially at the high end. While the IPCC’s vision of the uncertainty as to the true value of the climate sensitivity included a “fat tail” at the high end (that is, a non-negligible possibility that the true climate sensitivity was greater than 6°C), the new Science paper put the kibosh on that notion, concluding “In summary, using a spatially extensive network of paleoclimate observations in combination with a climate model we find that climate sensitivities larger than 6 K are implausible.” And adding “Assuming paleoclimatic constraints apply to the future as predicted by our model, these results imply lower probability of imminent extreme climatic change than previously thought.”

A pretty provocative finding to say the least!

(more…)




November 8, 2011

A new, lower estimate of climate sensitivity

Filed under: Climate Forcings

There is word circulating that a paper soon to appear in Science magazine concludes that the climate sensitivity—how much the earth’s average temperature will rise as a result of a doubling of the atmospheric concentration of carbon dioxide—likely (that is, with a 66% probability) lies in the range 1.7°C to 2.6°C, with a median value of 2.3°C. This is a sizeable contraction and reduction from the estimates of the climate sensitivity given by the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4), in which the likely range is given as 2.0°C to 4.5°C, with a best estimate of 3.0°C.

(more…)




October 24, 2011

Natural Variability Still Plays Large Role in Winter Climate

Filed under: Climate Forcings, Solar

The last couple of winters across the central and eastern United States as well as much of Europe were on the cold and snowy-side of things, to say the least. And of course, anytime there is some type of weather misery, a particular segment of the population likes to trot out global warming as the culprit. Cold, snowy, winters are no exception (despite your apparent (mis)conception as to what global “warming” would entail). Ironically, a subset of this same segment of folks was fingering global warming as the reason for the string of warmer-than-normal winters immediately preceding our past two shiverers (Figure1).

Now comes word that things other than global warming can lead to winter weather extremes. While that may come as shocker to some, it should be a snoozer to the vast majority.

(more…)




Next Page »

Powered by WordPress