Tag: carbon emissions

You Ought to Have a Look: On Fixing Science

You Ought to Have a Look is a regular feature from the Center for the Study of Science. 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.

This week we focus on an in-depth article in Slate authored by Sam Apple that profiles John Arnold, “one of the least known billionaires in the U.S.” Turns out Mr. Arnold is very interested in “fixing” science. His foundation, the Arnold Foundation, has provided a good deal of funding to various research efforts across the country and across disciplines aimed at investigating how the scientific incentive structure results in biased (aka “bad”) science. His foundation has supported several high-profile science-finding replication efforts, such as those being run by Stanford’s John Ioannidis (whose work we are very fond of) and University of Virginia’s Brian Nosek who runs a venture called the “Reproducibility Project” (and who pioneered the badge system of rewards for open science that we previously discussed). The Arnold Foundation has also provided support for the re-examining of nutritional science, an effort lead by Gary Taubes (also a favorite of ours), as well as investigations into the scientific review process behind the U.S. government’s dietary guidelines, spearheaded by journalist Nina Teicholz.

Apple writes that:

In my conversations with Arnold and his grantees, the word incentives seems to come up more than any other. The problem, they claim, isn’t that scientists don’t want to do the right thing. On the contrary, Arnold says he believes that most researchers go into their work with the best of intentions, only to be led astray by a system that rewards the wrong behaviors.

This is something that we, too, repeatedly highlight at the Center for the Study of Science and investigating its impact is what we are built around.

Apple continues:

[S]cience, itself, through its systems of publication, funding, and advancement—had become biased toward generating a certain kind of finding: novel, attention grabbing, but ultimately unreliable…

“As a general rule, the incentives related to quantitative research are very different in the social sciences and in financial practice,” says James Owen Weatherall, author of The Physics of Wall Street. “In the sciences, one is mostly incentivized to publish journal articles, and especially to publish the sorts of attention-grabbing and controversial articles that get widely cited and picked up by the popular media. The articles have to appear methodologically sound, but this is generally a lower standard than being completely convincing. In finance, meanwhile, at least when one is trading with one’s own money, there are strong incentives to work to that stronger standard. One is literally betting on one’s research.”

A CO2-Induced Increase in Subtropical North Atlantic Coccolithophore Abundance

Coccolithophores are calcifying phytoplankton that comprise the base of marine food webs all across the world ocean. They play an important role in the cycling of carbon into the deep ocean and act as a feedback to climate change. Anything that alters their function or abundance, therefore, could have significant impacts on marine ecosystems and global climate. Thus, it is no surprise that scientists are interested in how coccolithophores will respond to future changes in atmospheric CO2 and climate. And in this regard, Krumhardt et al. (2016) say there has been “much speculation [that has] inspired numerous laboratory and mesocosm experiments, but how they are currently responding in situ is less well documented.” Working to provide just such an in situ analysis, the team of four researchers thus set out to analyze coccolithophore abundance in the subtropical North Atlantic over the period 1990 to 2014.

To accomplish their objective, Krumhardt et al. used coccolithophore pigment data collected at the Bermuda Atlantic Time-series Study (BATS) site (located at 31.7°N, 64.2°W in the Sargasso Sea) in conjunction with satellite estimates of surface chlorophyll and particulate inorganic carbon as a proxy measure of coccolithophore abundance. Results of their analysis revealed that “coccolithophore populations in the North Atlantic subtropical gyre have been increasing significantly over the past two decades. More specifically, they note there was a 37 percent increase in euphotic zone-integrated (integrated from 140 m depth) in coccolithophore pigment abundance at BATS and a larger 68 percent increase in the upper 30 m of the water column (see figure below). Such findings, in the words of the authors, add to those of a growing number of studies showing that coccolithophores in the North Atlantic “are increasing in abundance and are likely stimulated by additional carbon from anthropogenic sources.”

Elevated CO2 Stimulates the Growth of Papaya

Papayas are spherical or pear-shaped fruits known for their delicious taste and sunlit color of the tropics. Upon his arrival to the New World, Christopher Columbus apparently could not get enough of this exotic fruit, reportedly referring to it as the “the fruit of angels.” And the fruit of angels it may indeed be, as modern science has confirmed its value as a rich source of important vitamins, antioxidants and other health-promoting substances to the consumer.

Papaya production has increased significantly over the past few years to the point that it is now ranked fourth in total tropical fruit production after bananas, oranges and mango. It is an important export in many developing countries and provides a livelihood for thousands of people. It should come as no surprise, therefore, that scientists have become interested in how this important food crop might respond to increasing levels of atmospheric CO2 that are predicted for the future.

Such interest was the focus of a recent paper published in the scientific journal Scientia Horticulturae by Cruz et al. (2016). Therein, the team of five researchers examined “the effect of the elevated CO2 levels and its interaction with Nitrogen (N) on the growth, gas exchange, and N use efficiency (NUE) of papaya seedlings,” as they note there are no publications examining such for this species to date. To accomplish their objective, Cruz et al. grew Tainung #1 F1 Hybrid papaya seeds in 3.5 L plastic pots in a climate-controlled greenhouse at the USDA-ARS Crops Research Laboratory in Fort Collins, Colorado under two different CO2 concentrations (390 or 750 parts per million) and two separate N levels (8 mM NO3- or 3 mM NO3-). CO2 fumigation was performed for only 12 hours per day (during the day, 06:00 h to 18:00 h) and N treatments were applied to the pots weekly as a nutrient solution to reach the desired N levels. The experiment concluded 62 days after treatment initiation.

In discussing their findings, Cruz et al. report that compared to ambient levels of CO2, elevated CO2 increased photosynthesis by 24 and 31 percent in the low and high N treatments, respectively. Plant height, stem diameter and leaf area in the high N treatment were also enhanced by 15.4, 14.0 and 26.8 percent, respectively, and by similar amounts for the height and stem diameter in the low N treatment. Elevated CO2 also increased the biomass of leaf, stem plus petiole, and root dry mass of papaya plants regardless of N treatment, leading to total dry mass enhancements of 56.6 percent in the high N treatments and 64.1 percent in the low N treatments (see figure below).

Figure 1. Total dry mass of papaya plants grown in controlled chambers at two different CO2 concentrations (High and Low; 750 and 390 ppm) and two different N treatments (High and Low; 8 mM NO3- or 3 mM NO3-). Adapted from Cruz et al. (2016).

Figure 1. Total dry mass of papaya plants grown in controlled chambers at two different CO2 concentrations (High and Low; 750 and 390 ppm) and two different N treatments (High and Low; 8 mM NO3- or 3 mM NO3-). Adapted from Cruz et al. (2016).


Cruz et al. also report that “significant, but minor, differences were observed in total N content (leaf plus stem + petiole plus roots) between plants grown at different CO2 concentrations, but the same N levels.” Consequently, plant Nitrogen Use Efficiency (NUE) – the amount of carbon fixed per N unit – was around 40 percent greater in the CO2-enriched environments, regardless of the N level in the soil.

Commenting on their findings, Cruz et al. write that contrary to some other studies, which have suggested that low N reduces plant responses to increased CO2 levels, they found no such decline. In fact, their data indicate that elevated CO2 “alleviated the effect of low N on dry matter accumulation in papaya,” which they surmised is at least partially explained by a larger leaf area and higher rate of photosynthesis per leaf area unit observed under elevated CO2.

In light of all of the above, Cruz et al. conclude that “an increase in the atmospheric CO2 concentration [is] beneficial for dry mass production of papaya and alleviate[s] the negative effects of N reduction in the substrate on papaya growth.” Thus, in the future, those who cultivate this fruit of angels should find an angel in the ongoing rise in atmospheric CO2.



Cruz, J.L., Alves, A.A.C., LeCain, D.R., Ellis, D.D. and Morgan, J.A. 2016. Interactive effects between nitrogen fertilization and elevated CO2 on growth and gas exchange of papaya seedlings. Scientia Horticulturae 202: 32-40.

Elevated CO2: A Key Driver of Global Greening Observations

Despite a constant barrage of stories portraying rising atmospheric carbon dioxide (CO2) as a danger and threat to the planet, more and more scientific evidence is accruing showing that the opposite is true. The latest is in a paper recently published in the journal Scientific Reports, where Lu et al. (2016) investigated the role of atmospheric CO2 in causing the satellite-observed vegetative greening of the planet that has been observed since their launch in 1978.

It has long been known that rising CO2 boosts plant productivity and growth, and it is equally well-established that increased levels of atmospheric CO2 reduce plant water needs/requirements, thereby improving their water use efficiency. In consequence of these two benefits, Lu et al. hypothesized that rising atmospheric CO2 is playing a significant role in the observed greening, especially in moisture-limited areas where soil water content is a limiting factor in vegetative growth and function. To test their hypothesis, the three scientists conducted a meta-analysis that included 1705 field measurements from 21 distinct sites from which they evaluated the effects of atmospheric CO2 enrichment on soil water content in both dryland and non-dryland systems.

A Century of Precipitation Trends in Victoria, Australia

In the debate over CO2-induced global warming, projected impacts on various weather and climate-related phenomena can only be adjudicated with observed data. Even before the specter of dreaded global warming arose, scientists studied historical databases looking for secular changes or stability. With the advent of general circulation climate models, using historical data, scientists can determine whether any observed changes are consistent with the predictions of these models as atmospheric carbon dioxide increases. An example of the pitfalls in such work was recently presented by Rahmat et al. (2015), who set out to analyze precipitation trends over the past century at five locations in Victoria, Australia. More specifically, the authors subjected each data set to a series of statistical tests to “analyze the temporal changes in historic rainfall variability at a given location and to gain insight into the importance of the length of data record” on the outcome of those tests. And what did their analyses reveal?

When examining the rainfall data over the period 1949-2011 it was found that all series had a decreasing trend (toward less rainfall), though the trends were significant for only two of the five stations. Such negative trends, however, were reversed to positive in three of the five stations when the trend analyses were expanded over a longer time domain that encompassed the whole of the 20th century (1900-2011 for four stations and 1909-2011 for the fifth one). In addition, the two stations with statistically significant negative trends during the shorter time period were also affected by the longer analysis. Though their trends remained negative, they were no longer statistically significant when calculated over the expanded 112 years of analysis. In summation, in the expanded analysis the “annual rainfall time series showed no significant trends for any of the five stations.”

In light of the above findings, Rahmat et al. write that “conclusions drawn from this paper point to the importance of selecting the time series data length in identifying trends and abrupt changes,” adding that due to climate variability, “trend testing results might be biased and strongly dependent on the data period selected.” Indeed they can be; and this analysis shows the absolute importance of evaluating climate model projections using data sets that have been in existence for sufficiently long periods of time (century-long or more) that are capable of capturing the variability of climate that occurs naturally. And when such data sets are used, as in the case of the study examined here, it appears that the modern rise in CO2 has had no measurable impact on rainfall trends in Victoria, Australia.



Rahmat, S.N., Jayasuriya, N. and Bhuiyan, M.A. 2015. Precipitation trends in Victoria, Australia. Journal of Water and Climate Change 6: 278-287.

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.



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.