Paul Clarke reviews the fight between science and deniers over whether climate change is real.

When Swedish scientist Svante Arrhenius constructed the first model of the influence of atmospheric carbon dioxide on climate, in 1896, he predicted that a doubling of CO2 due to fossil fuel burning alone would take 500 years and lead to temperature increases of 3–4°C. A little out but not bad for a first attempt! He was also the first to identify human industrial activity as the main source of new CO2 but, somewhat ironically, as it is an argument still used by some sceptics today, he said that the main effect was that the world could look forward to “more equable and better climates, especially as regards the colder regions of the Earth”. Arrhenius won the Nobel Prize for his work in chemistry: his model of the greenhouse effect was largely ignored until it was picked up as a major topic by the International Geophysical Year (IGY) in the 1950s.

What a Beautiful World

The US National Academies of Sciences, Engineering and Medicine (NAS) proposed a comprehensive series of global geophysical activities to span the period July 1957-December 1958. This strange choice of an 18-month “year” was because the IGY was modelled on the International Polar Years of 1882–83 and 1932–33. It was similarly intended to allow scientists from around the world to take part in a series of co-ordinated observations of various geophysical phenomena. Eventually 67 countries became involved but you could be forgiven if its significance has passed you by. Unless that is you happen to be a Steely Dan fan in which case you will remember IGY (What a Beautiful World). Written by Donald Fagan in the 1980s, this questions what happened to the post-war optimism in the ability of science to solve all our problems, typified by the Year.

Certainly it represented a mid-20th century highpoint in scientific co-operation with Soviet and American participants pooling their efforts despite the Cold War. Special attention was given to the Antarctic as the largest unexplored area on the planet and research on ice depths yielded radically new estimates of the earth's total ice content (as well as leading to the Antarctic Treaty). IGY Antarctic research contributed to improved meteorological prediction and to advances in the theoretical analysis of glaciers as researchers developed balloons that could ascend to the outer reaches of the atmosphere to gather information on radiation, ozone and CO2.

While the “one world” attitude promoted by the IGY may have dissipated, there is no doubt that the international efforts it set in motion would later bear fruit as scientists began to focus on air pollution and climate change problems in the second half of the 20th century. World centres were established during the Year to manage the unprecedented quantities of data that came flooding in and that would later serve to enable scientists from all over the world to access the information they needed. But there was a problem…

Knee-deep in data

Given that the average smart phone now has greater computing power than NASA used to land men on the moon, it is difficult to imagine how scientists coped with the scale of data collection they engaged in during the 1960s. To take one example, the National Climate Data Center (NCDC), which is the world's largest active archive of weather data, described this period as follows: “From storage rooms to hallways, punch card file cabinets containing the nation's archive of climate data filled every conceivable space at the National Weather Records Center in 1966, creating a maze for employees to manoeuvre through. Punch cards were stored everywhere, and over half a billion cards were on hand with new cards being generated every day.”

Indeed, there was such concern that the NWRC building might collapse because of the sheer weight of the 40 million cards that many of them were moved to the basement. Fortunately, an increased awareness of climate impacts in 1970s and 1980s coincided with huge efforts to transfer this invaluable data from cards to film and eventually magnetic tape. In just a few years the irreplaceable data was to move from cards, which had been introduced in the US to assist with the 1890 National Census, to being stored on the internet.

Early warnings

In 1988 a climate scientist, who had been studying the conditions on Venus before turning his attention to our own planet, told a US Senate hearing that “the greenhouse effect has been detected and is changing our climate now”. The scientific community could, he went on, “ascribe with a high degree of confidence a cause and effect relationship” between greenhouse gases and global warming. The first World Conference on the Changing Atmosphere took place that same month, with the United Nations setting up the Intergovernmental Panel on Climate Change (IPCC) before the year was out. In a magazine article coinciding with these early efforts, a Harvard University professor warned: “If we choose to take on this challenge, it appears that we can slow the rate of change substantially, giving us time to develop mechanisms so that the cost to society and the damage to ecosystems can be minimised. We could alternatively close our eyes, hope for the best, and pay the cost when the bill comes due.”

An Inconvenient Truth

In 2006, former Vice President Al Gore was still using the phrase “global warming” in his documentary “An Inconvenient Truth”, which explained the concept and presented the mounting scientific evidence that humans are treading a dangerous path if they fail to reduce carbon emissions. Unfortunately, sceptics had begun echoing Arrhenius and suggesting that “warming” sounded quite pleasant ("It's freezing and snowing in New York — we need global warming!" (D. Trump)) so scientists began to move to the description “climate change” as this would better encompass a whole range of effects from heat waves and rising sea levels to droughts, floods, fires and catastrophic storms.

How bad can it be?

In October 2018, the IPCC “Special Report on 1.5 degrees” was released, spelling out the science behind its assertion that the world has far less time available than was previously thought if it is to turn the tide with regard to climate change. The dramatic, far-reaching, and possibly irreversible consequences of surpassing 1.5 degrees of warming are less than 12 years away, the report warned. It failed to impress everyone, however, with President Trump, when asked about the findings that unchecked global warming would wreak havoc on the US economy, replying: "I don't believe it."

A 2018 World Bank report, which focuses on three regions (South Asia, Sub-Saharan Africa and Latin America) that together represent 55% of the developing world’s population, argued that climate change would push tens of millions of people to migrate within their countries by 2050. It projected that, without concrete climate and development action, just over 143 million people — or around 2.8% of the population of these three regions — could be forced to move within their own countries to escape the slow-onset impacts of climate change.

They will, it suggested, migrate from less viable areas with lower water availability and crop productivity and from areas affected by rising sea level and storm surges. The poorest and most climate-vulnerable areas would be hardest hit. These trends, the report went on, alongside the emergence of “hotspots” of climate in- and out-migration, would have major implications for climate-sensitive sectors and for the adequacy of infrastructure and social support systems. It concluded that internal climate migration would likely rise through 2050 and then accelerate unless there were significant cuts in greenhouse gas emissions.

What do experts know?

In an interview with Sky News just before the 2016 referendum, Michael Gove famously said "people in this country have had enough of experts". While this rather glib reply was intended to cast doubt on forecasts of post-Brexit doom by “organisations with acronyms”, it undoubtedly reflected a fact of modern life, namely that access to the internet has made everyone an expert (or at least given them access to their own “evidence”). While scientists working in this field have spent decades gathering the data that they need to support their forecasts of the catastrophic impact of failure to address climate change, anyone can set up a webpage (or tweet) arguing that this is just fake news. Whether this is done by those with an economic interest in maintaining the use of fossil fuels, or by someone who simply cannot understand the difference between climate and weather ("It's really cold outside, they are calling it a major freeze, weeks ahead of normal. Man, we could use a big fat dose of global warming!" (D. Trump)), social media is awash with those who received the news that 2018 was, globally, the fourth-hottest year on record with total equanimity, and are equally unmoved by reports from NASA that 2018's temperatures rank behind only those of 2016, 2017 and 2015.

NASA’s temperature analyses incorporate surface temperature measurements from 6300 weather stations, ship- and buoy-based observations of sea surface temperatures, and temperature measurements from Antarctic research stations. However those who wish to argue against climate change have no problem with dismissing the arguments of 97% of the world’s scientists when these can be “refuted” by, for example, a retired US television weatherman (Anthony Watts, who maintains the “Watts Up With That?” website). He claims that this is “the world's most viewed site on global warming and climate change”; he also described recent climate change findings by the National Oceanic and Atmospheric Administration as “a yawner”.

Once a sceptic…

As Dr John Cook, from the Centre for Climate Change Communication at George Mason University, Virginia, said: “Misinformation spreads easily, and can have profound consequences for society if left uncorrected. Climate science is particularly problematic because it describes such a complex system.” His team of researchers examined more than 40 common climate science denialist claims and found that, in a variety of different ways, all demonstrated erroneous reasoning.

Unfortunately, those wanting to cast doubt on the science of climate change can always find high level support with former Australian Prime Minister Tony Abbott, for example, telling the Global Warming Policy Foundation (GWPF) in London: “It's climate change policy that's doing harm. Climate change itself is probably doing good; or at least, more good than harm. There's the evidence that higher concentrations of carbon dioxide — which is a plant food after all — are actually greening the planet and helping to lift agricultural yields.”

In the UK, Nigel Lawson founded the GWPF in order to oppose climate change mitigation policies and has called for the IPCC to be shut down, arguing that the anthropogenic climate change it describes is merely “alarmist”. His book, “An appeal to reason: A cool look at global warming”, was dismissed in the journal Nature by Sir John Houghton (co-chairman of the IPCC) as neither cool nor rational and as indicating that Lord Lawson had not read the IPCC reports he trashes. Last year, the BBC was criticised by Ofcom after Lord Lawson was left unchallenged when he (incorrectly) told Radio 4's Today programme that the IPCC had confirmed there had not been an increase in extreme weather events for the last decade. "The programme did not clearly signal to listeners that his view on the science of climate change ran counter to the weight of scientific opinion in this field,” Ofcom said.

Stick to the facts

A synthesis of consensus estimates on human-caused global warming carried out in 2016 found that somewhere between 90% and 100% of scientists in the field agree humans are responsible for climate change, with most of the studies finding 97% consensus among publishing climate scientists. Furthermore, the greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.

These experts (with apologies to Mr Gove) all agree that every one of the past 40 years has been warmer than the 20th century average, that 2016 was the hottest year on record and that the 12 warmest years on record have all occurred since 1998. Furthermore, over the past 130 years, the global average temperature has increased 1.5°F, with more than half of that increase occurring over the past 35 years, and detailed records of past CO2 levels from ice core studies showing that these levels are higher today than at any point in the last 800,000 years.

Deloitte, the largest professional services network in the world, seems to have accepted the arguments. Launching a June 2019 call for businesses to take action to address the problem, it said: “Climate change is an existential threat that demands urgent attention; there can be no more ‘business as usual’ if companies are to protect their value, manage risks and future-proof their organisations.” The time to act, it concluded, is now.

Last reviewed 3 September 2019