A very short history of climate change research

The story of scientists discovering climate change is longer than many of us tend to imagine. We’ve had a sense that what humans do might effect the climate since Antiquity. Studies of glaciers in the mid 18th century got people wondering what had changed since the Ice Age. It was back in 1824 that French physicist Joseph Fourier first started talking about something called the ‘greenhouse effect’. He already knew the atmosphere protected us from the sun. What was new was the suggestion that the composition of this atmosphere might change, and that could lead to a warming of the Earth, a bit like a greenhouse warms its contents.

A few decades later, in 1861, Irish physicist John Tyndall identified the gases he thought might cause such an effect, including carbon dioxide. A keen mountaineer, Tyndall had a hands-on knowledge of Alpine glaciers and was drawn to the puzzle of their history. Based at London’s Royal Institution, he didn’t just sit in a lab on his own and write letters to other scientists. Rather, he devised public demonstrations, drawing huge crowds in both London and for international tours. He also had a great beard.

Despite Tyndall’s commitment to public engagement, the idea of CO as a greenhouse gas might have been left underdeveloped if it had not been picked up by Swedish chemist, Svante Arrhenius. He was also puzzled by the Ice Age, and figured CO might offer an answer. By 1896 Arrhenius had calculated that cutting CO₂ in the atmosphere by half could lower the temperature in Europe by 4-5°C. A colleague of Arrhenius, Arvid Högbom, thought it might be worth looking at the CO emitted by factories too, not just volcanoes and natural carbon sinks like trees or oceans.

They didn’t realise at the time, but that’s a significant point; the moment we realised human activities were adding a gas to the atmosphere which we thought might cause global warming. As scientists of the time remarked, we were ‘evaporating’ coal mines into the air. Still, realising the significance of this, and taking action, is another matter.

Following Arrhenius’ work, we also see the development of climate scepticism. That’s another thing that is quite old, even if – just like the science it responds to – the people and motivations of the movement have changed a lot over time. The initial scepticism was, arguably, quite reasonable. Arrhenius had simplified the system to make his calculations, and the lab equipment could have been better. The main barrier to the idea being picked up, however, was probably just that scientists turned their attention to other topics. Even Arrhenius wasn’t too worried. Scepticism wasn’t so much the problem as a general feeling of ‘meh’.

In the 1930s, Guy Callendar – an engineer by profession, but a keen meteorologist in his spare time – used weather stations’ records to show that temperatures had risen over the previous century. He also notes the increase in CO concentrations over the same period, and suggested a link. This was dismissed by meteorologists at the time, but we now know it is fundamental.

In 1957, it became clear that the oceans absorbs far less CO₂ than previously predicted

So although we had the bones of a theory for anthropogenic global warming, people remained pretty unconcerned. We might be ‘evaporating’ coal mines (and oil rigs, and gas pipes) into the air, but anyone who noticed this also assumed the oceans would absorb it. The inaccuracy of this assumption was gradually uncovered in the middle of the 20th century, via an unlikely source. Researchers at the University of Chicago were studying the use of radioactive carbon-14 to find the age of ancient materials like Egyptian mummies. More than a matter for archaeologists, military interest in radiation meant the research attracted support from the US Air Force. These techniques were then picked up by chemist Hans Suess, who first applied it to studying carbon in trees and then, crucially, oceans. Working with oceanographer Roger Revelle – who was also assisted by military in his work, this time the Navy – researchers concluded oceans could only absorb about a tenth of the carbon predicted. In the conclusion to his paper, Revelle wrote the haunting line: ‘Human beings are now carrying out a large scale geophysical experiment’. That was 1957.

1957 was also the International Geophysical Year. Time for a musical break? Here’s Don Fagen’s song about it. Because science policy does occasionally chart on the Billboard Hot 100.

One of the key projects the International Geophysical Year offered support for was Dr Charles D. Keeling’s project measuring the concentration of carbon dioxide in the atmosphere. This has been running from an observatory in Hawaii since 1958, now led by his son Ralph. The graph of the resulting data is known as the Keeling Curve: Keeling after scientists, and curve because it is going up. Today, you can follow it on Twitter. Although crucial to our understanding of climate change, it struggles to maintain funding, just as it always has. By the 1980s, this data was supplemented with empirical research studying air bubbles trapped deep in Antarctic and Greenland ice caps. A sort of natural time capsule, the ice had encased the gases of previous eras allowing scientists to study its composition. You can see one of the ice cores on display at the London Science Museum.

Ice core at the London Science Museum

Perhaps it was just the Cold War putting a stench of global catastrophe in the air, but the emerging climate science started to worry people. In 1965, a report from the Environmental Pollution Panel of the US President’s Scientific Advisory Committee included a section on carbon dioxide from fossil fuels as ‘the invisible pollutant’. Chaired by Roger Revelle and supported by Charles Keeling, it repeats the line that ‘Man is unwittingly conducting a vast geophysical experiment’ and perhaps too-dryly concludes that it ‘could be deleterious from the point of view of human beings’.

Throughout the 1960s and 70s, we also see the growth of a popular green movement. The major NGOs were initially hesitant to work on climate change. Like many scientists and politicians, they were maybe just more concerned with other issues. However, it is probably fair to say climate change is at the centre of most green activism today. Running alongside this is a rise in sceptic activism, although it has tended to be a phenomena limited to the English-speaking world.

1972 saw the first UN environment conference. It might have been more interested in whaling than climate, but it was a start, and led to the establishment of the United Nations Environment Programme. This, in turn, established the Intergovernmental Panel on Climate Change (IPCC) in 1988. The IPCC doesn’t carry out its own research. Rather it looks at the literature published elsewhere, relying upon the work of thousands of scientists the world over. It is probably best understood as a machine of scientific advice to governments. Each IPCC is a massive undertaking. There have been five in total: 1990, 1995, 2001, 2007 and 2014. Since the third report, they’ve been split into three Working Groups; one on the physical science explanation of what is going on, one on the impacts of climate change and, finally, one considering options for limiting emissions and mitigating climate change. They are due to offer a synthesis report later this year. Though drafts have already been leaked, it’s not much of a surprise; the point of the IPCC is to collate, asses and summarise what we already know.

In 1992, at the Rio Earth Summit, the United Nations Framework Convention on Climate Change (UNFCCC) was established. It’s formally a treaty, but doesn’t contain anything legally binding. Rather, it provides a framework for negotiating specific international treaties. Or to put it another way, it’s an agreement to have a lot of meetings. They have met annually since 1995 under ‘Conferences of the Parties’ (better known as COPs). COP3 is perhaps the most significant. Held in Kyoto in 1997, it led to the ‘Kyoto Protocol’ which aimed to add some teeth to the initial framework, with binding targets for greenhouse-gas reductions. There were high hopes for the 2009 COP15 in Copenhagen, but it was largely considered, at best, a disappointment. The world is still waiting for strong global action on climate change.

And all this time, we’ve kept emitting. The fossil fuel based growth which Victorians like Fourier, Tyndall and Arrhenius were already familiar with has only increased and engrained itself further into society. Against the backdrop of people measuring the climate and waking up to what that might mean, we’ve done much more to increase global warming than stop it. We knew 350ppm was a dangerous point on the Keeling Curve – a whole campaign was named after it – but still let ourselves go far beyond that. And yet, the story of climate change is still a hopeful one. Often despite ourselves, we noticed, and we’ve at least started to take action. We humans are really clever, even if we can also be phenomenally dumb. We’ve done some things, so we can do more.


  1. Marc Hudson

    Much quicker read that Spencer Weart! Thanks very much. I was under impression that the first two reports also were in 3 working groups (with controversy during 1990 that all three reports were produced simultaneously). Also, (and I totally understand the space/attention limits) it would have been nice to give a shout out to Bert Bolin, who did so much. But it’s a brilliant quick summary of how (we know) we got into this mess.

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