In 1992, Bill Clinton was elected US President, Euro Disney opened in Paris, the Olympic Games were held in Barcelona, and Wayne's World was one of the big movies of the year.
Whether the Earth Summit of that year ranks among these notable events very much depends on its legacy and whether it has led us to addressing one of the great issues facing us today: climate change.
It has now been 20 years since the original Earth Summit in Rio de Janeiro - or to give it its full name: the United Nations Conference on Environment and Development.
Back in 1992, 172 countries sent 108 heads of state to the Brazilian city, with another 2,400 representatives from non-governmental organisations also in attendance.
We tend to think of Rio 1992 in terms of measures to address climate change, although it is important to remember that the remit of the Summit also included: controlling the production of toxic substances - such as lead in petrol; the development of new public transport systems to prevent congestion and air pollution; addressing the scarcity of water; and, last but not least, seeking ways to develop renewable energy in order to replace fossil fuels linked to climate change.
A key element of the Summit was to set up the United Nations Framework Convention on Climate Change. The aim was to ensure countries stabilised their greenhouse gas emissions at a level that would prevent runaway anthropogenic (human-caused) climate change.
By 1992, the link between climate change and fossil fuels had become a concern. The years 1990 and 1991 had been confirmed as the two warmest years on record since 1850. (How much more focussed might politicians' minds have been had they known that 14 out of the following 15 years would be even warmer?)
Even back in 1992, the link between fossil fuels and a warmer world was nothing new. In fact, as long ago as the Industrial Revolution scientists were beginning to question what effect the burning of coal would have on our atmosphere.
In 1859, Irish physicist John Tyndall discovered that some gases block incoming infrared radiation from the Sun. He suggested that changes in the concentration of these gases could bring about climate change. As long ago as 1896, Swedish chemist Svante Arrhenius had calculated the amount of global warming caused by human emissions of carbon dioxide.
During the 1960s and 70s the idea that the Earth would cool as the Sun weakened briefly held sway. But the developing scientific theory of rising global temperatures and supporting observational evidence brought global warming to the fore once again.
The ability of humankind to take effective action in light of strong scientific evidence had been shown in the 1970s and 80s, when the serious impact of chlorofluorocarbons (CFCs) and ozone on the environment became apparent. The Montreal Protocol of 1987, which placed severe restrictions on the production of these gases showed that, by concerted action, humankind could control its environment.
In response to concerns about anthropogenic climate change, the United Nations set up the Intergovernmental Panel on Climate Change (IPCC) to report on and analyse scientific findings. Immediately, the IPCC warned that strong action would be necessary to combat rising global temperatures.
The Rio Summit was merely the first step in addressing the issue of climate change. The agreed restrictions on greenhouse emissions were entirely voluntary. Very few countries actually met these targets.
Legally binding targets were to follow in 1997 when the Kyoto Protocol was agreed. One hundred seventy-eight countries signed up, and the targets took effect in 2005. In the meantime, the IPCC has continued to issue its reports based on the available scientific evidence.
The first report in 1990 reflected the limited evidence and uncertainty in the scientific predictions. Nevertheless, it stated "with confidence" that carbon dioxide has been responsible for over half the enhanced greenhouse effect.
While it also predicted an increase in global mean temperature of three degrees Celsius in the 21st century, there was an uncertainty range of two to five degrees.
By the time the fourth report was published in 2007, the wording reflected a growing body of evidence supporting the theory. "Warming of the climate system is unequivocal," it stated. Anthropogenic warming in the last century was revised upwards from between 0.3 and 0.6 degrees Celsius in the 1990 report, to around 0.75 degrees. The report found that there was a 90 per cent chance that the global temperature rise since the mid-20th century was anthropogenic in origin.
On the face of it, the ever-accumulating evidence supporting an increase in global temperatures should lend greater weight to the forthcoming summit. But, now as then, attitudes towards climate change reflect the multifaceted nature of the problem.
In a time of global depression, jobs and economies are seen as the priority by many politicians. Growth in the BRIC economies is slowing, the eurozone is in crisis, the US has an upcoming presidential election, and the "Arab Spring" reverberates around many Middle Eastern countries.
"Some island nations fear that rising sea levels as a result of a warmer world will threaten their very existence."
Some still deny the existence of a problem; others who acknowledge it feel that it is pointless to address the problem directly and that the wise approach is to work towards more efficient economies and technologies.
Acceptance of the science of climate change has been a battle. From the famous "hockey stick graph" published by Michael Mann in 1998, which revealed the rapid rise in global temperatures since the Industrial Revolution, to the leaking of documents at the University of East Anglia's Climate Research Unit, the war between the majority of the scientific community and a small but vociferous minority has been hard-fought.
But as politicians arrive in Rio this week, they will be faced with a mass of evidence difficult to ignore. The summit will leave politicians facing stark choices.
For some, it is a no-brainer - some island nations fear that rising sea levels as a result of a warmer world will threaten their very existence. Others see any emissions limits as a threat to their development.
Whatever the outcome of the Summit, we have come a long way in our understanding of climate change, and Rio 1992 should be seen as the point at which we began to take climate change seriously.
Source: Al Jazeera