By Andy May

Wow! Our new paper “Carbon Dioxide and a Warming Climate are not problems,” in the American Journal of Economics and Sociology has struck a nerve, judging by the traffic about it on twitter. An anonymous twitter troll who calls himself “Bonus @TheDisproof” has published what he (or she) calls a list of errors in our paper that is getting a lot of views and likes from the usual alarmist suspects, some of whom are probably actually people as opposed to “bots.” One person who has reposted the “Bonus” critique is Michael Mann. Michael Mann says, “This article is a Crok.” I don’t think he was complementing my co-author Marcel Crok, but then Mann is well known for crude and juvenile remarks. Mann might still remember Marcel for his 2005 award-winning article about Mann’s notorious hockey stick graph. Marcel was the first who wrote extensively about the critique of McIntyre and McKitrick on this graph.

I’ve tried answering most of Bonus’s criticisms on twitter, but the responses keep disappearing. Not sure what is going on there. Normally answering an anonymous troll isn’t worth the bother but judging from my email and phone calls about this one, I should. So, this post addresses his list of complaints to date. I’ll indent the complaints and number them.

Bonus:

“A new climate denial paper in an obscure low impact, non-climate related journal has popped up. It is written by Marcel Crok @marcelcrok & Andy May @Andy_May_Writer, both of which spread disinfo on a regular basis. I’ll go through just some of their multiple errors here.”

First of all, I don’t know of any disinformation that either Marcel or I have posted anywhere. All our posts and the paper are solidly supported by references and/or data. Bonus’s list of “errors” follows.

Bonus #1

“Their paper falsely claims “. Sea level rise is currently a very modest two millimeters per year”. They cite their own non peer reviewed source (A Clintel climate denial “report”) but omit that both tide gauges AND satellite data shows a faster rate and an accelerating rate.”

First of all, the Clintel Report we cite, “The Frozen Climate Views of the IPCC: An Analysis of AR6” was extensively peer-reviewed by a team of four independent reviewers as well as the eight named authors of the chapters. There were also two other members of the Clintel team that helped review selected chapters. The Clintel team reside in 8 countries and work in academia, government, and industry. Their professions cover numerous disciplines including economics, geology, meteorology, chemistry, physics, molecular biology, atmospheric physics, and climatology. See the book for more details.

There are two chapters in the book that deal with sea level, one by Kip Hansen and the other by Ole Humlum. Both agree, along with those who peer-reviewed the work, that the rate of sea-level rise over the past 150 years or so is about 1-2 mm/year according to tide gauges. It varies up and down cyclically over the 150-year period, so one can (and some do) cherry-pick intervals in an attempt to show acceleration, but no definitive acceleration is apparent in the record, at least on climate scale periods of time. One reason is that the data, whether satellite or tide gauge, is not accurate enough at the present very slow rate of sea level rise to be definitive, as discussed in the book.

Sea level fell during the Little Ice Age as more and more water was taken up to enlarge glaciers and the ice caps during that very cold period. When the Little Ice Age ended around 1850, the expanded glaciers began to melt, and sea level began to rise. This is all normal. The overall rate of increase was between 0.8 and 1.95 (very likely range) mm/year according to AR6 Chapter 9 (IPCC, 2021, p. 1287) and other sources.

More recently we gained the ability to estimate sea level using satellites. Problems reconciling the satellite measurements and the tide gauge records have made sea level rise estimates difficult since the first satellite data became available in 1992. A much more detailed discussion is available in Chapters 5 and 10 in the “The Frozen Climate Views…” (Crok & May, 2023).

Bonus #2

“They cited just two climate proxy papers Vinther et al 2009 and Rosenthal et al 2003 [sic] and attempted a cherry pick. But they ignored that Vinther et al uses data that ends decades ago so omits the rapid and significant warming in Greenland since then.”

The two temperature proxy papers we cite are (Vinther, et al., 2009) and (Rosenthal, Linsley, & Oppo, 2013). We plotted the entire proxy record from both sources back to the beginning of the Holocene approximately 9,000BC, nothing was cherry-picked. Vinther and Rosenthal’s data ends in the early to mid-20th century because the proxies for later than that haven’t formed yet. The Greenland ice is still snow or firn and the animal shells in the Makassar Strait that Rosenthal used are not stabilized in the ocean floor sediments yet. This is how all proxies work. The only way to incorporate modern temperatures into the graph is to mix instrumental data with the proxies which must be done very carefully for number of reasons, the modern data must be made to conform to the proxy dataset. We did this in our figure 4 from (May & Crok, 2024), shown below.

Figure 1. Figure 4 from (May & Crok, 2024)

To validly compare proxies to modern temperatures you must average the modern temperatures over the temporal resolution of the proxies and compare them at the proxy location. There are very few proxies in 9000BC, so a valid global average temperature (proxy or otherwise) isn’t possible. Proxies are very low resolution compared to the daily temperatures we gather today with thermometers. Further, besides resolution problems, proxy temperatures just are not very accurate, those in figure 1 are among the better proxies and their accuracy is ±0.3 to 0.4 deg C.

Figure 4 in our paper (figure 1 above) does do a valid comparison for the Makassar Strait record by averaging the 500-meter depth temperatures from the University of Hamburg’s ocean database from 2006-2016 (Gouretski, 2019). This temperature is shown as a red box on the figure, presumably Bonus missed this or didn’t understand it. The temporal resolution of the Vinther and Rosenthal records in the twentieth century is about 20 years between temperature estimates, so 2006-2016 is close to that, it is also the time period with the best data in the Makassar Strait. Earlier than 2006 the data gets poor very quickly.

Thus, what Bonus wants us to do is invalid and erroneous. We did the most valid comparison to modern instrumental temperatures possible. To see the Greenland data treated in the same way, see this post, figure 1. In it, the modern data in the Greenland area is compared to the Alley Greenland ice core record for the past 4,000 years.

Bonus #3

In addition: Rosenthal et al 2009 AND Rosental et al 2013 shows current GLOBAL SST is currently above the level seen in the very regional Rosenthal 2003 paper.

Again, Bonus gets his Rosenthal papers mixed up. The data we present is the Rosenthal (2013) data and it is not the SST (sea surface temperature) data he is referring to. We use the intermediate water temperature (500-meter depth) because it represents SST temperatures in the northern Pacific Ocean. Bonus is just confused here and didn’t read the paper carefully enough.

Bonus #4

Not to mention that collectively climate proxies show that current global temperatures are well above anything in the human civilization history. See also Marcott et al 2021.

Again Bonus is confused, no one knows what the global average surface temperature was in 9000BC, or even in 1000AD. Proxies are not that accurate. Plus according to AR6, (Kaufman, McKay, & Routson, 2020) and (Kaufman & McKay, 2020b) the median/average temporal resolution of the proxies used in the graph he shows from Marcott and Shakun (2021) is 164 years between temperatures or the entire industrial period record since 1880. You can’t compare current rates of warming from daily measurements to rates from that proxy data. All you can do is average all the temperatures since 1880 and compare it to selected proxies at the specific proxy locations. Nothing else is a valid comparison. See this post by Renee Hannon for a further discussion of this issue.

Bonus #5

They repeat Bjorn Lomborg’s false claim that climate related deaths have declined 99% since the early 20thC. Lomborg’s claim [is] debunked.

Bonus shows a video clip of someone (unidentified, like Bonus himself) claiming that Lomborg misrepresented the EM-DAT data he used to create his now famous graph, which comes from a peer-reviewed paper he wrote in 2020 (Lomborg, 2020). The graph is shown below.

Figure 2. Lomborg’s graph of deaths due to climate change (in blue) and other causes (in red). (Lomborg, 2020)

The anonymous video is a rather tiresome complaint that Lomborg prepared the data incorrectly and presented it incorrectly, the narrator’s arguments don’t hold water. It is very clear that no matter how the data are presented, deaths from extreme weather have decreased radically since the early twentieth century. One could quibble about the classifications of the deaths by EM-DAT or the data prep forever, but the underlying idea is sound. Besides, Lomborg’s paper is peer-reviewed and we don’t even know who Bonus or the narrator in the video are. I’ll take peer-reviewed over anonymous drivel any day.

Bonus #6

They mention a paper on CO2 Greening (Zhu et al 2016) but fail to mention a more detailed analysis found that the greening dominated in China and India and was due to “programs to conserve and expand forests” and “intensive cultivation of food crops”.

This demonstrates that Bonus has not read the papers he cites very well. Zhu (the paper we cite, (Zhu, Piao, & Myneni, 2016)) calculates that 70% of Earth’s global greening in the modern period is due to CO2 and about 13% is due to fertilizer and land use changes by humans. The non-peer-reviewed NASA blog post that Bonus cites, states that China and India account for 30% of the global greening, there is no inconsistency in the numbers from the two sources, they are about different things. Both articles agree that the Earth is greener in recent years, but the NASA blog post is silent on the impact of CO2. Bonus was confused and in over his head.

Bonus #7

“They claim more CO2 benefits plants but ignore the greater harmful side effects of climate”

CO2 is pumped into greenhouses to achieve more rapid growth and Craig Idso (Idso, 2013) has estimated the monetary benefit to farming output of increased CO2 is $3 trillion since 1961. What are the harmful side effects of additional CO2 that our anonymous Bonus has to offer? Again, he refers to an anonymous non-peer-reviewed video. His source tweet is here, I did not try and figure out which source was which, and Bonus provided no help. The reader is welcome to try and figure it out, I will not bother with it.

The first argument from the video is that CO2 is not the only limiting factor to plant growth, plants also need water, pests are a problem, etc. These have absolutely nothing to do with CO2 and are red herrings. Then they say the rate of additional growth due to more CO2 lessens as CO2 increases. So what? You still get more growth. Then they say additional CO2 benefits weeds as well as crops, well duh, of course that is the case. Weed control is a separate issue.

Then they claim that recently crop production has declined. Not according to the data in Ourworldindata.org and FAO, see below.

Figure 3. Global cereal production from ourworldindata.org

Then they claim that additional CO2 increases global temperature and drought. As our peer-reviewed paper (May & Crok, 2024) makes clear the connection between CO2 and temperature is possible, but not proven and meteorological drought is decreasing or staying the same [(Klotzbach, Bowen, Pielke, & Bell, 2018), (Crok & May, 2023, pp. 142-157), and (Pielke, 2019)], and not increasing globally according to AR6 (IPCC, 2021, pp. 1579-1580). Finally, they say, global warming increases the growing season, true, but then they complain that this increases the use of water and gives pests more time to get to the crop. A rather silly argument, longer growing time is a good thing, whether caused by CO2 or not. The video is anonymous and unsourced, like Bonus, whereas our sources are all peer reviewed.

Bonus #8

Near the end of their paper they cite an Exxon corporate document for their claim that we will need more fossil fuels.

The data we cite is from ExxonMobil’s yearly Outlook. It is widely used as a very credible source of energy production and consumption data. It is used, and cited, globally, like similar reports generated by BP and Shell are used. This is pure prejudice and not a valid criticism, Exxon’s Outlook is a very credible source.

Bonus #9

Marcel Crok is responsible for a climate denial “clintel declaration” signed mostly by fossil fuel employees, oil and gas geologists, fossil fuel lobby group members non-experts, conspiracy theorists and not a single actively publishing climate scientist.

This is completely untrue, like nearly everything Bonus writes. The 1900+ Clintel signatories include fossil fuel employees and retirees (including me) of course, but also hundreds of scientists and engineers who are or were employed by academia and in other industries. There are many, many Clintel signatories who are actively publishing climate scientists, including both Marcel and myself, as well as many others. I should mention that “climate scientist” is not a real field, most “climate scientists” have degrees in physics (like William Happer), geology (like Michael Mann or Andy May), atmospheric physics (Richard Lindzen and Judith Curry), or meteorology.

Bonus #10

Oh and Marcel Crok’s clintel released a climate denial film with @Martin_Durkin that was debunked.

Michael Durkin’s film (supported by Tom Nelson and Marcel Crok) has never been debunked and is well grounded in the peer-reviewed literature (see here for a full annotated bibliography) unlike the non-peer-reviewed and unsourced films by the anonymous filmmakers cited by Bonus.

I’ve followed the very popular and excellent Climate The Movie: The Cold Truth since it first came out and it has not been debunked by anyone credible that I’m aware of.

Bonus #11

The paper also claims no change in extremes linked to climate change which is false. I noted that Crok and May have admitted in their Clintel report on IPCC AR6 they didn’t read the full AR6 IPCC report so that might be why they didn’t find anything. i.e. they didn’t look.

We did not claim that extreme weather didn’t change, we claimed and documented that most extreme weather trends either have not changed in modern times or have decreased and that overall the impact of extreme weather declined as a percent of GDP. These are well documented facts reported in “The Frozen Climate Views of the IPCC: An Analysis of AR6” (Chapters 11-13) and in AR6. There is no evidence that extreme weather or the impact of extreme weather has increased.

As for Marcel Crok and Andy May not having read all 10,000 pages of AR6, this is true. I seriously doubt many people have. However between the entire 13-member team we assembled to write “The Frozen Climate Views of the IPCC: An Analysis of AR6” we very likely did. AR6 is ridiculously long.

Bonus #12

the plot thickens…It turns out that the Journal’s calls for papers on climate seems to be courting fossil fuel funded climate change denier groups. Their call for papers links to the CO2 coalition (a fossil fuel funded lobby group that spreads disinfo) which May is a member of.

The CO2 Coalition is a very good organization that I am a proud member of. It spreads no disinformation that I’m aware of and Bonus provides no examples. This propensity of the alarmists to lie about and disparage good organizations and people only because they disagree with them is reprehensible.

Bonus #13

……and if this is the Marty Rowland who is special editions editor at the American Journal of Economics and sociology Journal look at what he says about climate change. Wow, looks like a journal that likes climate change denial and disinformation?!

And the character assassination attempts continue. Marty Rowland has the opinion that “climate change” is a religion. It is. The “true believers,” such as Bonus or Michael Mann, will not discuss or debate the issue as true scientists would do, they just try and beat down their opponents with ad hominem attacks on twitter. One is reminded of the Spanish Inquisition.

Bonus #14

AJES ranking, not good.

This is a silly argument. The American Journal of Economics and Sociology has been around since 1941 and is well respected. This sort of argument is very juvenile, like the attacks on Marty Rowland, Marcel Crok, and myself.

Conclusions

The anonymous “Bonus” somehow created quite a stir on twitter, yet we don’t know who he or she is, could be a twelve-year-old with his mother’s phone for all we know. Bonus cites very few peer-reviewed articles and when he does, he often gets them wrong as in the Rosenthal article mix up discussed above. Yet, Michael Mann cites him in twitter, which gives you an idea about Mann’s academic integrity.

None of Bonus’s claims are true or supportable. Beware of what you read from anonymous sources. Bonus’s critique is a biased and emotional screed with no merit.

Download the references here.