UK climate change deniers are peddling false claims about polar sea ice
The UK’s main club for climate change deniers, the Global Warming Policy Foundation, is continuing to spread misinformation about the impacts of rising levels of greenhouse gases in the atmosphere, recently publishing a misleading pamphlet on polar sea ice.
On 14 December 2021, the Global Warming Policy Foundation published a pamphlet called ‘Polar sea ice and the climate catastrophe narrative’ by J. Ray Bates, an adjunct professor of meteorology at University College Dublin. Professor Bates joined the so-called ‘Academic Advisory Board’ of the Foundation in September 2021. He is one of the few members of this group of 27 men who has qualifications and training in climate-related science.
According to the Foundation’s media release on the pamphlet, Professor Bates says: “Climate models failed to predict the growth in Antarctic sea ice, and they missed the recent marked slowdown of sea-ice decline in the Arctic.” But the pamphlet’s attempts to justify these claims show that they are misleading at best , if not inaccurate.
In its discussion of Arctic sea ice, the pamphlet starts not with the scientific evidence but instead with an ill-informed attack on the former Vice President of the United States, Al Gore. Many climate change deniers are obsessed with Mr Gore because of his effectiveness in communicating about the risks of climate change.
The pamphlet states: “In December 2007, former US vice-president Al Gore, in his Nobel Peace Prize acceptance speech in Oslo, referred to scientific studies warning that the Arctic sea ice was ‘falling off a cliff’. He highlighted forthcoming model results that projected largely ice-free Arctic summers in ‘as little as seven years’.”
In fact, Mr Gore drew attention to more than one study in his speech on 10 December 2007, stating:
“Last September 21, as the Northern Hemisphere tilted away from the sun, scientists reported with unprecedented distress that the North Polar ice cap is “falling off a cliff.” One study estimated that it could be completely gone during summer in less than 22 years. Another new study, to be presented by U.S. Navy researchers later this week, warns it could happen in as little as 7 years.”
The results of the latter study referred to by Mr Gore, by researchers at the United States Naval Postgraduate School and the Polish Academy of Sciences, were presented on 12 December 2007 at the annual Fall Meeting of the American Geophysical Union, and were reported by the BBC. In outlining the study’s findings, Professor Wieslaw Maslowski said the projection that sea ice could disappear in the Arctic summer as early as 2013 had taken account of data between 1979 and 2004. A later presentation by Professor Maslowski, from June 2008, showed that the projection of an ice-free Arctic by summer 2013 was not based on a model but instead on an extrapolation of the trend in decreasing ice volume between 1997 and 2004.
Professor Bates’s pamphlet wrongly claims that the US Naval Postgraduate School study “used a regional model of the sea ice–ocean system in the Arctic, constrained using observational data for the 12-year period 1996–2007, and concluded that the Arctic would be nearly ice-free in summer by 2016 (plus or minus three years)”.
In fact, here Professor Bates has selectively cited an updated version of the research presented by Professor Maslowski and his colleagues in 2007 that was eventually published in the journal Annual Review of Earth and Planetary Sciences in 2012. That paper included a review of a wide range of studies as well as the most recent results from the research by Professor Maslowski and his team using the Naval Postgraduate School Arctic Modeling Effort (NAME) regional ice-ocean model. It presents a time series of monthly mean Arctic sea ice volumes estimated by the NAME model and recent satellite measurements.
The paper states:
“According to model results, sea ice volume has changed little during the 1980s through the mid-1990s (i.e., no noteworthy trend is present during this time period), in contrast to the time period after 1995. This is qualitatively consistent with trend estimates for the ice extent (Stroeve et al. 2011b) and thickness and demonstrates a strengthening of the trends in all three sea ice parameters on the basis of a statistically significant difference in linear regression slopes computed for the two time periods.”
The paper concludes:
“The modeled evolution of Arctic sea ice volume appears to be more strongly correlated with changes in ice thickness than with ice extent as it shows a similar negative trend beginning around the mid-1990s. When considering this part of the sea ice–volume time series, one can estimate a negative trend of −1,120 km3 year−1 with a standard deviation of ± 2,353 km3 year−1 from combined model and most recent observational estimates for October–November 1996–2007. Given the estimated trend and the volume estimate for October–November of 2007 at less than 9,000 km3 (Kwok et al. 2009), one can project that at this rate it would take only 9 more years or until 2016 ± 3 years to reach a nearly ice-free Arctic Ocean in summer. Regardless of high uncertainty associated with such an estimate, it does provide a lower bound of the time range for projections of seasonal sea ice cover. (We do note that other published estimates also have large or indeterminate uncertainties.)”
It should be noted that the Technical Summary of the contribution of Working Group I of the Intergovernmental Panel on Climate Change to the Sixth Assessment Report, published in August 2021, concluded: “The annual Arctic sea ice area minimum will likely [likelihood of 66%-100%] fall below 1 million km2 at least once before 2050 under all assessed SSP [Shared Socioeconomic Pathway] scenarios. This practically sea ice-free state will become the norm for late summer by the end of the 21st century in high CO2 emissions scenarios (high confidence).”
Misrepresentation of the changes in Arctic (and Antarctic) sea ice
The most blatantly misleading section of Professor Bates’s pamphlet is its presentation of the record of the average Arctic sea ice extent, as measured by satellites each September since 1979. Instead of showing the unequivocal downward trend in extent of about 81,200 square kilometres per year between 1979 and 2021, it shows a trendline for the cherry-picked period between 2007 and 2021, noting it shows a much slower decline of about 8,200 km2 per year, almost 10 times lower than the long-term trend.
The pamphlet states:
“There was a marked sea-ice decline for a period following 1996. However, since 2007, rather than disappearing as projected, the September sea ice has exhibited a much slower rate of decline, remaining in the region of 4.5 million km2. If the statistical trend in the most recent 15-year period were maintained, it would take over 500 years for the Arctic to become ice-free in September.”
However, measuring trends from a small number of points in a noisy dataset is fraught with problems. If Professor Bates had instead selected the data since 2013, he would have found a more quickly declining trend of about 84,700 km2 per year. On this basis, according to Professor Bates’s flawed method, the reduction in Arctic sea ice extent has accelerated since 2013, as this figure illustrates.
Source: Author’s plot of data published by the United States National Snow and Ice Data Center
Professor Bates also neglects to mention that all of the 15 lowest Arctic ice extents on record have occurred from 2007 onwards. Yet while his pamphlet appears to admit the illegitimacy of his cherry-picking method, stating: “strong reliance cannot be placed on a linear trend measured over such a short period”, he wrongly adds, “it must be remembered that the dramatic projections of sea-ice loss publicised by Al Gore were based on a model that used observational data over an even shorter period”. With this statement he fails to acknowledge that Professor Maslowski based his projection on the mean sea ice volume measured between October and November, which shows a clear change in trend from 1996 onwards.
Laughably, Professor Bates’s pamphlet adopts the opposite approach for Antarctic ice extent. It presents the mean September measurement for each year between 1979 and 2021 and notes that the trend is an increase of about 8,500 km2 per year. The pamphlet states: “It can be seen that, contrary to what the models have been projecting, the trend during this period is in the direction of slightly increasing Antarctic sea-ice extent.” However, if Professor Bates had chosen to cherry-pick the data for the past 15 years since 2007, he would have found that there is a negative trend of about 38,600 km2 per year. Professor Bates does not explain why he prefers different timescales for measuring trends in the Arctic and Antarctic.
It is worth noting that the sea ice extents in the Arctic and Antarctic are subject to different local influences that result in a clear downward trend in the Northern hemisphere but a slight upward trend in the Southern hemisphere. As the United States National Oceanic and Atmospheric Administration summarises: “Climate change has a discernible influence on Arctic sea ice, but it has a complicated, messy influence on Antarctic sea ice. (Meanwhile, the Antarctic ice sheets are losing mass.)”
Bearing hallmarks of the GWPF
These shenanigans over polar sea ice have echoes of the Global Warming Policy Foundation’s attempts to cast doubt on the rate of global warming. When it was launched in 2009, the Foundation used a ‘logo’ that purported to represent the record of annual global mean surface temperature. However, as part of its discredited campaign to fool the public and policymakers into believing that global warming had stopped in 1998, the Foundation only included annual temperature from 2000 onwards, hence hiding the evidence of the long-term warming trend. The ‘logo’ was updated each year to add the latest annual figure, but the Foundation abandoned it in October 2021, presumably because the temperature record since 2000 was inconveniently showing unequivocal warming.
The publication of Professor Bates’s flawed pamphlet demonstrates that the Global Warming Policy Foundation still cannot be trusted to tell the truth about climate change.