Earlier this week, Viscount Ridley demonstrated yet again why he and other so-called “lukewarmers” cannot be trusted by the public on climate change.

He used his regular column in ‘The Times’ to attack David Attenborough the BBC’s wonderful ‘Blue Planet II’ for daring to highlight the scientific evidence that climate change is having a detrimental impact on the world’s oceans.

Although Viscount Ridley, who describes himself as a “lukewarmer”, praised the programme for drawing attention to the dangers of plastic for marine wildlife, he criticised its coverage of ocean acidification and declining polar sea ice.

His column talked up the recent successes in parts of the world of halting the decline in some species that are suffering from human activities, such as overfishing. This positive spin about the environment, playing down the evidence of problems, is a key feature of Viscount Ridley’s writing, and is embodied by his book ‘The Rational Optimist’ and his blog of the same name.

So he took exception to a sequence in the first episode of Blue Planet II, broadcast on BBC 1 on 29 October and available to view on BBC iPlayer, which showed a female walrus and her calf struggling to find a patch of sea ice on which to ‘haul out’. The programme pointed out that this was linked to the effects of global warming on the Arctic. But Viscount Ridley wrote: “Walruses have hauled out on shore, or on what’s left of the ice at that season, forever. The main thing that has changed is that there are now more walruses, and more polar bears feasting on them, throughout the Arctic”.

In writing this, Viscount Ridley was ignoring the documented scientific evidence that was the basis for the programme’s claim. Scientists have been pointing out for many years that Pacific walruses, in particular, have been affected by a reduction in sea ice during the late summer and autumn, when Arctic sea ice reaches its minimum level.

Viscount Ridley’s column notably did not even acknowledge the fall in Arctic sea ice that has been occurring. The most recent analysis by the United States National Snow and Ice Data Center shows that the sea ice extent in September has been dropping by 13.2 per cent per decade since satellite measurements began in 1979.

And that reduction is having real consequences for Pacific walruses. A new paper by a group of researchers at the United States Geological Survey, the Fish and Wildlife Service and the University of California concluded: “Declining extent of summer sea ice in the Chukchi Sea has caused Pacific walruses to increase use of coastal haulouts and decrease use of more productive offshore feeding areas”.

The authors noted: “Virtually the entire Pacific walrus population winters in the ice pack of the Bering Sea, where they breed. In spring, most of the population, including almost all of the females and young, follow the retreating sea ice into the Chukchi Sea where they remain until they return to the Bering Sea as ice reforms in autumn.”

They added: “Sea ice in the Chukchi Sea has retreated north of the continental shelf in late summer or autumn during 8 of the last 10 yr (2007–2016). As sea ice has become less available in recent years, walruses have been increasingly using terrestrial haulouts on the coasts of Alaska and Chukotka.”

Viscount Ridley’s claims are also shown to be false by a recent assessment by the United States Fish and Wildlife Service of the health of the Pacific walrus population. It stated: “For the Pacific walrus, the most significant risk factor looking into the future is the effects of climate change (sea-ice loss)”.

The Agency refused to list the Pacific walrus as threatened because of uncertainty about the future impacts, stating: “While we have high certainty that sea-ice availability will decline as a result of climate change, we have less certainty, particularly further into the future, about the magnitude of effect that climate change will have on the full suite of environmental conditions (e.g., benthic productivity) or how the species will respond to those changes”.

So ‘Blue Planet II’ was absolutely correct to draw attention to the difficulties that walruses are having as a result of the rapid decrease in Arctic sea ice, and which Viscount Ridley chose to ignore.

He also complained about a sequence in the the final programme, broadcast on 10 December, that described the consequences of ocean acidification. When carbon dioxide dissolves in water, it forms carbonic acid. Rising carbon dioxide emissions from the burning of fossil fuels and other human activities has been reducing the pH of sea water and making it more acidic.

The programme illustrated the impact of this ocean acidification through a recording of Professor Chris Langdon of the University of Miami pouring a weak acid into an empty fish tank. Sea shells in the tank began to fizz and dissolve on contact with the acid because they are made of calcium carbonate.

David Attenborough, the programme’s presenter, asked: “And how much more acidic is this than the present ocean?” Professor Langdon replied: “This is more concentrated than the pH of the ocean but it accelerates the process so that we can see something visually. So what is happening is these shells are made out of calcium carbonate and the acid is dissolving them and coral reefs are made out of the same material as these shells here.”

Viscount Ridley was right to describe this as “highly misleading”. Ocean acidification is not causing calcium carbonate shells to dissolve in this way. The fizzing of the shells recorded for the programme was caused by the release of carbon dioxide as the acid reacted with the calcium carbonate. In fact, despite ocean acidification, sea water remains weakly alkaline. But there is clear evidence that the change in pH of about 0.1 over the past few decades is making it more difficult for marine animals to build and grow shells and skeletons, as Professor Langdon has discussed in many of his recent scientific papers. And in some cases, the shells of marine animals are dissolving because ocean acidification has reduced the stability of calcium carbonate in sea water.

A paper, co-authored by Professor Langdon about the impact of global warming and ocean acidification on corals in the Caribbean, stated: “In addition to absorbing heat, the ocean has absorbed one-third of the CO2 produced by anthropogenic activities. This has resulted in a decrease of 0.02 pH units decade-1 over the last 30 years, a phenomenon known as ocean acidification. This decrease in pH is accompanied by a decline in the saturation state of calcium carbonate which impairs the ability of corals and other calcifying organisms to form skeletons.”

Notwithstanding the error in the programme, Viscount Ridley was wrong to dismiss the threat from ocean acidification and to cherry-pick quotes selectively from a 2010 study by Spanish researchers which concluded: “Active biological processes and small-scale temporal and spatial variability in ocean pH may render marine biota far more resistant to ocean acidification than hitherto believed”.

More recent assessments of the impacts of ocean acidification indicate that Viscount Ridley’s claim is complacent. For instance, the secretariat of the Convention on Biological Diversity published a synthesis in 2014 of the scientific evidence and concluded: “Ocean acidification represents a serious threat to marine biodiversity”, while also noting that “many gaps remain in our understanding of the complex processes involved and their societal consequences”.

Finally, in a throwaway comment in brackets, Viscount Ridley’s column stated: “Coral bleaching, a different issue, is more serious, but more temporary”. This was another example of Viscount Ridley understating the threat of global warming.

The final programme of ‘Blue Planet II’ showed the affects of coral bleaching in the Great Barrier Reef in 2016. A new study published in the ‘Bulletin of the American Meteorological Society’ indicated that the “2016 global coral bleaching event was severe: 93% of the northern, 700km stretch, of the Australian Great Barrier Reef (GBR) coral was bleached and by June, >60% of this coral was killed in association with heat stress”. It concluded that “GHG [greenhouse gas] warming of regional sea surface temperatures was the primary increase in risk for the 2016 GBR bleaching”.

In addition, a recent review of the scientific literature found that coral reefs take about 10 to 20 years to recover fully from bleaching events, but as these increase in frequency due to global warming, they may start to disappear altogether from 2030 onwards.

Overall, Viscount Ridley’s article was a classic example of ‘lukewarmer’ propaganda, playing up uncertainties and slightly positive impacts while downplaying or ignoring the risks of climate change. ‘The Times’ also allowed him not to disclose his affiliation as a member of the “Academic Advisory Council” of the Global Warming Policy Foundation, the campaign group set up by Lord Lawson to lobby against policies to reduce greenhouse gas emissions.

Viscount Ridley seems keen to keep hidden his links with the Foundation. As the Desmog Blog revealed earlier this week, the register of the House of Lords, where Viscount Ridley is a Conservative hereditary peer, records that his staff include John Constable, a critic of renewable energy. But the register does not mention that Constable is also the “energy editor” of the Foundation’s official lobbying arm.


Bob Ward is policy and communications director at the Grantham Research Institute on Climate Change and the Environment and the ESRC Centre for Climate Change Economics and Policy at the London School of Economics and Political Science.

Keep in touch with the Grantham Research Institute at LSE
Sign up to our newsletters and get the latest analysis, research, commentary and details of upcoming events.