Tag: climate change

Elevated CO2 Reduces the Inhibitory Effect of Soil Nitrate on Nitrogen Fixation in Pea Plants

Introducing their work, Butterly et al. (2016) write that rising atmospheric CO2 concentrations are projected to increase the productivity of agricultural cropping systems in the future, primarily via enhanced photosynthesis and reduced evapotranspiration when water and nutrients are not limiting. One field crop that is economically important in many semi-arid locations is the common pea plant (Pisum sativum); yet according to Butterly et al., “few studies have examined the effects of elevated CO2 on field pea.” Therefore, in an attempt to rectify this situation, the team of four Australian researchers set out to examine the interactive effects of elevated CO2 and soil nitrate (NO3-) concentration on the growth, nodulation, and nitrogen (N2) fixation of pea plants. Nodules house bacteria that “fix” atmospheric nitrogen into ammonia, which serves as plant food.

The study was conducted in a semi-arid location at the SoilFACE facility of the Department of Economic Development, Jobs, Transport and Resources Plant Breeding Centre in Horsham, Victoria, Australia. There, pea plants were grown for a period of 15 weeks in Vertisol soils containing either 5, 25, 50 or 90 mg NO3--N kg-1 under either ambient (390 ppm) or elevated (550 ppm) carbon dioxide concentrations maintained using free-air CO2 enrichment (SoilFACE). It was the hypothesis of the researchers that “nodule establishment (nodule number), development (nodule mass) and function (nitrogenase activity, N derived from the atmosphere) would be progressively inhibited with increasing NO3- (nitrate) concentration, but these effects would be reduced under elevated CO2 via enhanced N demand due to greater photosynthetic activity and plant biomass accumulation.”

The results of their analysis confirmed the inhibitory effects of soil nitrate concentration on field pea plants growing under ambient CO2. In the elevated CO2 treatment, however, field pea plants had approximately 30 percent more biomass and were not affected by N level (see figure below). What is more, Butterly et al. report that “elevated CO2 alleviated the inhibitory effect of soil NO3- on nodulation and N2 fixation,” which impressive finding they say “is likely to lead to greater total N content of field pea growing under future elevated CO2 environments.” And the end result of these findings, they add, “indicate that field pea may perform well in semiarid agricultural systems under future CO2 concentrations irrespective of soil N status, and subsequent gains in N input via enhanced N2 fixation will be important for maintaining the N fertility of cropping systems.”

Now that is good news worth reporting!

Figure 1. Shoot (Panel A) and root (Panel B) biomass of field pea grown for 15 weeks under either an ambient (aCO2) or elevated (eCO2) carbon dioxide concentration and with 5, 25, 50 or 90 mg NO3--N kg-1 soil.

Figure 1. Shoot (Panel A) and root (Panel B) biomass of field pea grown for 15 weeks under either an ambient (aCO2) or elevated (eCO2) carbon dioxide concentration and with 5, 25, 50 or 90 mg NO3--N kg-1 soil.

 

Reference

Butterly, C.R., Armstrong, R., Chen, D. and Tang, C. 2016. Free-air CO2 enrichment (FACE) reduces the inhibitory effect of soil nitrate on N2 fixation of Pisum sativum. Annals of Botany 117: 177-185.

You Ought to Have a Look: The Hows and Whys of the Social Cost of Carbon

You Ought to Have a Look is a feature from the Center for the Study of Science posted by Patrick J. Michaels and Paul C. (“Chip”) Knappenberger.  While this section will feature all of the areas of interest that we are emphasizing, the prominence of the climate issue is driving a tremendous amount of web traffic.  Here we post a few of the best in recent days, along with our color commentary.

There are several notable pieces this week that relate to the social cost of carbon (SCC)—the government’s powerful tool to aid in justifying all manner of rules and regulations. The SCC is supposed to represent the negative externalities (i.e., projected economic damages in a projected society resulting from projected climate change) that are associated with the emissions of each ton of carbon dioxide. It was developed as a way to translate carbon dioxide emission reductions into dollars savings and to make the “benefits” of proposed climate actions hit closer to home for more people.

But as you may guess from the number of “projected”s in the above parenthetical, the SCC is so highly malleable that you can pretty much game it to produce any value desired—the perfect characteristic for an all-purpose economic cost/benefit tool wielded by an opportunistic and activist government.

The situation is well-described by American Enterprise Institute’s Benjamin Zycher in his recent post for The HillThe magic of the EPA’s benefit/cost analysis.”

Welcome to the fascinating world of EPA benefit/cost analysis… the administration conducted an “analysis” of the “social cost of carbon” (SCC), in order to generate an estimate of the marginal externality cost of greenhouse gas emissions (GHG). The problems with that analysis are legion, but the central ones are the use of global (rather than national) benefits to drive the benefit/cost comparison; the failure to apply a 7 percent discount rate to the streams of benefits and costs, despite clear direction from the Office of Management and Budget; and — most important — the use of ozone and particulate reductions as “co-benefits” of climate policies. The administration’s estimate is about $36 per ton in 2015 ($31 per ton in 2010).

And that is how a regulation yielding future changes in temperatures and sea levels approaching zero can be claimed to yield net benefits “exceeding $100 billion, making this a highly beneficial rule.” In the EPA’s benefit/cost framework, the actual effects of the policies literally are irrelevant; just compute the assumed reduction in GHG emissions, multiply by $36, and voila!

Zycher takes us through the absurdities of just how small the impact of Obama’s “climate” actions is on the actual climate and how the actions are enormously magnified they become when they are run through the social cost of carbon. He concludes:

It is the delegation of legislative powers to the regulatory agencies that has allowed such game-playing in pursuit of an ideological agenda. The only means with which to restore political accountability to the regulatory process is a requirement that all regulations be approved by Congress.

You can check out his entire article, here.

Sixty-Six Years of Island Shoreline Dynamics on Jaluit Atoll, Marshall Islands

According to a conventional narrative, tropical islands are eroding away due to rising seas and increasingly devastating storms. Not really, according to the recent work of Ford and Kench (2016).

Writing as background for their study, the two researchers state that low-lying reef islands are “considered highly vulnerable to the impacts of climate change,” where an “increased frequency and intensification of cyclones and eustatic sea-level rise [via global warming] are expected to accelerate shoreline erosion and destabilize reef islands.” However, they note that much remains to be learned about the drivers of shoreline dynamics on both short- and long-term time scales in order to properly project future changes in low-lying island development. And seeking to provide some of that knowledge, the pair of New Zealand researchers set out to examine historical changes in 87 islands found within the Jaluit Atoll (~6°N, 169.6°E), Republic of the Marshall Islands, over the period 1945-2010. During this time, the islands were subjected to ongoing sea level rise and the passage of a notable typhoon (Ophelia, in 1958), the latter of which caused severe damage with its >100 knot winds and abnormal wave heights.

So what did their examination reveal?

Analyses of aerial photographs and high-resolution satellite imagery indicated that the passage of Typhoon Ophelia caused a decrease in total island land area of approximately five percent, yet Ford and Kench write that “despite [this] significant typhoon-driven erosion and a relaxation period coincident with local sea-level rise, [the] islands have persisted and grown.” Between 1976 and 2006, for example, 73 out of the 87 islands increased in size, and by 2010, the total landmass of the islands had exceeded the pre-typhoon area by nearly 4 percent.

Such observations, in the words of Ford and Kench, suggest an “alternative trajectory” for future reef island development, and that trajectory is one of “continued island expansion rather than one of island withering.” And such expansion is not just limited to Jaluit Atoll, for according to Ford and Kench, “the observations of reef island growth on Jaluit coincident with sea level rise are broadly consistent with observations of reef islands made elsewhere in the Marshall Islands and Pacific (McLean and Kench, 2015).” Given as much, it would thus appear that low-lying islands are not as vulnerable to climate change as previously thought.

 

Reference

Ford, M.R. and Kench, P.S. 2016. Spatiotemporal variability of typhoon impacts and relaxation intervals on Jaluit Atoll, Marshall Islands. Geology 44: 159-162.

McLean, R.F. and Kench, P.S. 2015. Destruction or persistence of coral atoll islands in the face of 20th and 21st century sea level rise? WIRES Climate Change 6: 445-463.

Taming the Greenland Melting Global Warming Hype

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

There is a new paper generating some press attention (e.g. Chris Mooney at the Washington Post) that strongly suggests global warming is leading to specific changes in the atmospheric circulation over the Northern Hemisphere that is causing an enhancement of surface melting across Greenland—and of course, that this mechanism will make things even worse than expected into the future.

We are here to strongly suggest this is not the case.

The new paper is by a team of authors led by Marco Tedesco from Columbia University’s Lamont-Doherty Earth Observatory. The main gist of the paper is that Arctic sea ice loss as a result of human-caused global warming is causing the jet stream to slow down and become wigglier—with deeper north-south excursions that hang around longer.  This type of behavior is referred to as atmospheric “blocking.”

If this sounds familiar, it’s the same theoretical argument that is made to try to link wintertime “polar vortex” events (i.e., cold outbreaks) and blizzards to global warming. This argument which has been pretty well debunked, time and time again.

Well, at least it has as it concerns wintertime climate.

The twist of the new Tedesco and colleagues’ paper is that they’ve applied it to the summertime climate over Greenland. They argue that global warming is leading to an increase in blocking events over Greenland in the summer and that is causing warm air to be “locked” in place leading to enhanced surface melting there. Chris Mooney, who likes to promote climate alarm buzzwords, refers to this behavior as “weird.” And he describes the worrysome implications:

The key issue, then, is whether 2015 is a harbinger of a future in which the jet stream keeps sending Greenland atmospheric systems that drive major melt — and in turn, whether the Arctic amplification of climate change is driving this. If so, that could be a factor, not currently included in many climate change simulations, that would worsen the ice sheet’s melt, drive additional sea level rise and perhaps upend ocean currents due to large influxes of fresh water.

As proof that things were weird over Greenland in recent summers, Tedesco’s team offers up this figure in their paper:

<--break- >

This chart (part of a multipanel figure) shows the time history of the North Atlantic Oscillation (NAO—a pattern of atmospheric variation over the North Atlantic) as red bars and something called the Greenland Blocking Index (GBI) as the black line, for the month of July during the period 1950-2015. The chart is meant to show that in recent years, the NAO has been very low with 2015 being “a new record low of -1.23 (since 1899),” and the GBI has been very high with the authors noting that “[c]oncurrently, the GBI also set a new record for the month of July [2015].” Clearly the evidence is showing that atmospheric blocking increasing over Greenland which fits nicely into the global warming/sea ice loss/wiggly jet stream theory.

So what’s our beef?

A couple of months ago, some of the same authors of the Tedesco paper (notably Ed Hanna) published a paper showing the history of the monthly GBI going back to 1851 (as opposed to 1950 as depicted in the Tedesco paper).

Here’s their GBI plotted for the month of July from 1851 to 2015:

This picture tells a completely different story. Instead of a long-term trend that could be related to anthropogenic global warming, what we see is large annual and multidecadal variability, with the end of the record not looking much different than say a period around 1880 and with the highest GBI occurring in 1918 (with 1919 coming in 2nd place). While this doesn’t conclusively demonstrate that the current rise in GBI is not related to jet stream changes induced by sea ice loss, it most certainly does demonstrate that global-warming induced sea ice loss is not a requirement for blocking events to occur over Greenland and that recent events are not  at all “weird.”  An equally plausible, if not much more plausible, expectation of future behavior is that this GBI highstand is part of multidecadal natural variability and will soon relax back towards normal values.  But such an explanation isn’t Post-worthy.

Another big problem with all the new hype is that history shows the current goings-on in Greenland to be irrelevant, because humans just can’t make it warm enough up there to melt all that much ice. For example, in 2013, Dorthe Dahl-Jensen and her colleagues published a paper in Nature detailing the history of the ice in Northwest Greenland during the beginning of the last interglacial, which included a 6,000 year period in which her ice core data showed averaged a whopping 6⁰C warmer in summer than the 20th century average. Greenland only lost around 30% of its ice with a heat load of (6 X 6000) 36,000 degree-summers. The best humans could ever hope to do with greenhouse gases is—very liberally—about 5 degrees for 500 summers, or (5 X 500) 2,500 degree-summers. In other words, the best we can do is 500/6000 times 30%, or a 2.5% of the ice, resulting in a grand total of seven inches of sea level rise over 500 years. That’s pretty much the death of the Greenland disaster story, despite every lame press release and hyped “news” article on it.

While you won’t find this kind of analysis elsewhere, we’re happy to do it here at Cato. 

References:

Dahl-Jensen, D., et al., 2013.  Eemian interglacial reconstructed from a Greenland folded ice core.  Nature 489, doi: 10.1038/nature11789.

Hanna, E., et al., 2016. Greenland Blocking Index 1851-2015: a regional climate change signal. International Journal of Climatology, doi: 10.1002/joc.4673.

Tedesco, M., et al., 2016. Arctic cut-off high drives the poleward shift of a new Greenland melting record. Nature Communications, DOI: 10.1038/ncomms11723, http://www.nature.com/ncomms/2016/160609/ncomms11723/full/ncomms11723.html

The Climate Alarm Death Knell Sounds Again

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.” 

Currently, details are few, but apparently the results of a major scientific study on the effects of anthropogenic aerosols on clouds are going to have large implications for climate change projections—substantially lowering future temperature rise expectations.

In a blog post from the Department of Meteorology of the University of Reading, Dr. Nicolas Bellouin describes some preliminary results from a research study he leads that is investigating the influence of aerosols on cloud properties.  The behavior of clouds, including how they are formed, how long they last, how bright they are, etc., plays a very large role in the earth’s climate system, and is considered the weakest part of global climate models. The climate model cloud deficiency results from a combination of scientific uncertainty about cloud behavior, as well as the modeling challenges that come from simulating the small spatial and temporal scales over which the important processes take place.

When it comes to the influence of human aerosol emissions on cloud properties, the scientific mainstream view is that aerosols modify clouds in such a way as to result in an enhanced cooling of the earth’s surface—a cooling influence which has acted to offset some portion of the warming influence resulting from human emissions of greenhouse gases (primarily from the burning of fossil fuels, like coal, oil, and natural gas to produce energy).  In the absence of this presumed aerosol cooling effect, climate models predict that the earth should warm at a much faster rate than has been observed.  A large cooling effect from aerosols was thus introduced in the early 1990s as a way to “fix” the climate models and bring them closer in line with the modest pace of observed warming. Despite that “fix,” climate models continue to overpredict the observed warming rate—which is bad enough news for climate models already.

You Ought to Have a Look: A Shout-Out to Lukewarming, a Look at the Republic of Science and a “Roundup” of EPA and Glyphosate

You Ought to Have a Look is a feature from the Center for the Study of Science posted by Patrick J. Michaels and Paul C. (“Chip”) Knappenberger.  While this section will feature all of the areas of interest that we are emphasizing, the prominence of the climate issue is driving a tremendous amount of web traffic.  Here we post a few of the best in recent days, along with our color commentary.

We’ve put together an interesting collection of articles this week for your consideration.

First up is a shout out to lukewarming from Bloomberg View columnist Megan McArdle. In her piece “Global Warming Alarmists, You’re Doing It Wrong,” McArdle suggests that lukewarmers have a lot to bring to the climate change table, but are turned away by the entrenched establishment and tarred with labels like climate “denier”—a label which couldn’t be further from the truth. McArdle writes:

Naturally, proponents of climate-change models have welcomed the lukewarmists’ constructive input by carefully considering their points and by advancing counterarguments firmly couched in the scientific method.

No, of course I’m just kidding. The reaction to these mild assertions is often to brand the lukewarmists “deniers” and treat them as if what they were saying was morally and logically equivalent to suggesting that the Holocaust never happened.

In her article, McArdle calls for less name calling and less heel digging and more open, constructive discussion:

There is a huge range of possible beliefs that go into assessing the various complicated theories about how the climate works, and the global-warming predictions generated by those theories range from “could well be catastrophic” to “probably not a big deal.” I know very smart, well-informed, decent people who fall at either end of the spectrum, and others who are somewhere in between. Then there are folks like me who aren’t sure enough to make a prediction, but are very sure we wouldn’t like to find out, too late, that the answer is “oops, catastrophic.”

These are not differences that can be resolved by name calling. Nor has the presumed object of this name calling – to delegitimize thoughtful opposition, and thereby increase the consensus in favor of desired policy proposals – been a notable political success, at least in the U.S. It has certainly rallied the tribe, and produced a lot of patronizing talk about science by people who aren’t actually all that familiar with the underlying scientific questions. Other than that, we remain pretty much where we were 25 years ago: holding summits, followed by the dismayed realization that we haven’t, you know, really done all that much except burn a lot of hydrocarbons flying people to summits. Maybe last year’s Paris talks will turn out to be the actual moment when things started to change – but having spent the last 15 years as a reporter listening to people tell me that no, really, we’re about to turn the corner, I retain a bit of skepticism.

How was this bit of advice from McArdle received by some of the loudest name-callers? Not well, as she describes in this follow-up:

Arctic Methane Scare Oversold

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

Methane is all the rage. Why? Because 1) it is a powerful greenhouse gas, that molecule for molecule, is some 25 times as potent as carbon dioxide (when it comes to warming the lower atmosphere),  2) it plays a feature role in a climate scare story in which climate change warms the Arctic, releasing  methane stored there in the (once) frozen ground, which leads to more warming and more methane release, ad apocalypse, and 3) methane emissions are  also be linked to fossil fuel extraction (especially fracking operations). An alarmist trifecta!

Turns out, though, that these favored horses aren’t running as advertised.