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A brief history of human understanding of climate change


Michael Cooper


December 2021

Part 2 – Modern Acceptance

In part one of this article, we looked at human understanding of our planet’s climate up until the mid-twentieth century.

We pick up this potted history in the late 1950s, a time when increased government investment was beginning to enable the scientific community to fully understand the looming crisis that humans had created…

The Keeling Curve and the post-war cool

As with many great innovations of humankind, many of the studies undertaken in the mid-twentieth century were funded for militaristic goals. The aftermath of the Second World War and the rise of the Cold War lent an urgency to all major military powers to understand more about the environment and climate to gain an advantage over their adversaries. However in 1958, American geochemist Charles David Keeling and his counterparts at the Scripps Institution outlined a method of recording carbon dioxide levels via a monitoring station in the centre of the Pacific Ocean. Information gathered from this observatory gave previously unmatched evidence of the upward curve of rising levels of greenhouse gases in the atmosphere.

In 1958 Charles David Keeling outlined a method of recording carbon dioxide levels

Within a year or two of Keeling’s data capture, digital technology had advanced to such a stage that future forecasting was made possible. These forecasts seemed to prove consistently (and somewhat alarmingly) that Guy Stewart Callendar’s estimations in the 1930s were correct: doubling atmospheric carbon dioxide emissions would result in a global temperature rise of 2°C, and that this might happen within a century.

As awareness of global warming became well-known, another potential impact of climate change began to be studied: global cooling. Scientists began to recognise that the post-war boom in aerosol sprays was having the effect of reflecting sunlight away from Earth. In what was to become one of the biggest arguments of ill-informed climate-change deniers, the planet cooled in the three decades following World War II.

As this period of cooler temperatures abated, however, the graph of the world’s average annual temperatures regained its upward momentum. This was due, in part, to the fact that while smog could float in the lower atmosphere for several weeks, carbon dioxide could persist for centuries.

Mercury peaks of the 1980s

Throughout the 1980s, global average temperatures continued to break records. The data was alarming, with the decade seeing fears grow and arguably the first real organisation societal push for serious change.

In 1987, the Montreal Protocol was established. An international treaty designed to protect the ozone layer by phasing out the numerous substances responsible for ozone depletion, it was agreed on 16th September, and entered into force on 1st January 1989. Due to its widespread implementation, the Montreal Protocol was hailed as the most positive example of international co-operation up until this point, with United Nations Secretary General Kofi Annan saying it represented “perhaps the single most successful international agreement to date”.

Nonetheless, 1988 was confirmed as the hottest year on record, and the impact on weather conditions gave rise to catastrophic fires and droughts across the planet. With the Montreal Protocol raising global awareness the previous year, seeing these effects first-hand urged people to sit up and take notice of the changes going on around them, and a movement was born.

The following year, the Intergovernmental Panel on Climate Change (IPCC) was formed by the United Nations; its remit was to provide the scientific data to gauge the political and economic impacts of the rising climate. The IPCC’s first actions were to warn of heatwaves, hurricanes and wildfires fuelled by rising sea temperatures – around this time, terms such as ‘El Nino’ entered the common vernacular and the view that massive changes to the way we live our lives were essential to life on the planet.

The science around the subject also began to give greater detail on which particular parts of the world were most at risk of impending catastrophes. In particular, melting polar ice caps could (or more accurately would) result in rising sea levels of up to a meter. This meant scientists could list the cities and towns that would sink below the ocean first…now people were really sitting up and starting to pay attention!

Within a year of these record-breaking temperatures being announced, the first carbon offset project was launched. Applied Energy Services, an American electric power company, financed an agriforest in Guatemala to offset the emissions of their new, coal-fired power plant in Connecticut. A tangible response to human impact on the climate was truly underway.

Kyoto and beyond…

In 1997, world leaders came together to announce the first global agreement on the reduction of greenhouse gas emissions. However, the Kyoto Protocol to the United Nations Framework Convention on Climate Change wasn’t officially declared until February 16, 2005 due to a complex ratification process, (an ominous portent for the issues of global political alignment that pervades today).

The protocol called for a reduction in the emission of six greenhouse gases (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride) in 41 countries plus the EU. The overall aim was to reduce emissions to 5.2% below 1990 amounts between 2008 and 2012.

At the point of signing, the United States sitting President was Bill Clinton. Efforts to achieve these targets took a significant blow, however, in 2001, when his successor George W. Bush announced the United States would not implement the protocol, stating it was “flawed in fundamental ways” and raising concerns that the deal would impact adversely on world economies.

As the climate change movement dealt with this blow, greenhouse gas emissions continued to grow rapidly year on year…

US politics, science (and scepticism) enters the mainstream…

In 2006, Clinton’s former Vice President Al Gore produced a documentary that would go further than any of the previous efforts to raise awareness of the climate crisis. The film – An Inconvenient Truth – made the scientific data accessible to the masses, and Gore was awarded the 2007 Nobel Peace Prize for his efforts.

As is the norm in the world of politics, if politician A takes a position, politician B from the opposing party must take the opposite stance. And unfortunately, there were many powerful people ready to take the opposite stance to Gore. Among them was future President Donald Trump, who repeatedly called the rising climate crisis a hoax and warned against taking any serious action for fear of detriment to the US economy. At one point, he even called for the Nobel committee to rescind Gore’s award.

As the political barometer swung from right back to left, the US returned to the table to affect real change when Bush’s successor, Barack Obama, signed the Paris Climate Agreement in 2015 at the French capital’s Climate Change Conference (otherwise known as COP21). The Paris Agreement saw some 197 countries pledge to cut their greenhouse gas emissions in a formal effort to prevent global temperature rises of 2°C. By this point, the scientific community overwhelmingly believed that this was the critical figure to avoid major catastrophes on a global scale.

As expected, however, the election of Donald Trump saw the US withdraw from the Paris Agreement, only for his successor Joe Biden to reinstate the commitment from the world’s largest power.

Empowering people…

In 2018, the world was introduced to a teenager who would become one of the loudest voices in the push to avoid the climate crisis. Greta Thunberg is the most prominent example of the modern climate activist, becoming a household name after playing a key role in the “School Strike for Climate” protests in her native Sweden.

Her raising of awareness of global climate issues immediately made world headlines and by late 2018, students in 24 countries were participating in organised climate strikes. In 2019, Greta was nominated for a Nobel Peace Prize and was a regular participant at events such as in the UN’s Climate Summits. Later that year, an estimated two million people took part in worldwide climate demonstrations, including more than one million protesters in Italy and several hundred thousand in Canada. Closer to home in Australia, thousands of students began striking on Fridays, disregarding Prime Minister Scott Morrison’s call for “more learning in schools and less activism”. Despite Morrison’s dismissal, politicians worldwide are being persuaded more and more by the rising numbers of activists and vocal scientists that climate change is an essential cause to support (and a potential vote winner). It is now widely recognised that the climate change crisis is the single biggest issue humankind must face.

The world has a long way to go to secure a planet that can support life as we know it, but one thing is for sure – we’ve come a very long way since extreme weather conditions first forced our ancient ancestors out of Africa.

Missed Part One? Click Here

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