The first use of the term global warming was in The Hammond Times in Indiana USA. The article, on 6 November 1957, reported that scientists were studying the effect waste gases could have on the carbon dioxide balance in the atmosphere. Although the study of greenhouse gases in the atmosphere dated back to the 1860s it was only in the 1950s that the first data were gathered to support the global warming theory. Global warming is predicted to have a significant effect on the world’s food supplies.

Global warming in the last 50 years
Source: NASA

We now talk about climate change, rather than global warming. However, it was a sharp increase in global temperatures during the 1980s that sparked alarm among scientists. Studies predicted heat waves, droughts and severe weather events such as hurricanes, as well as rising sea levels as polar ice caps melted. The first international agreement to reduce greenhouse gases, the Kyoto Protocol, was adopted in 1997.

In 2015, 195 countries signed the Paris Agreement, setting targets for the reduction of greenhouse gas emissions. After the election of US President Donald Trump, the USA walked away from that agreement. Meanwhile, scientists warn that climate change will have a significant effect on the world’s food supplies. One estimate suggests, for example, that even with warming of less than 2oC, the production of corn in the United States could be reduced by around 18 per cent.

The increased incidence of extreme weather events such as floods and droughts will further affect food production, while aquifers, vital to many irrigated areas, are being depleted. A National Academy of Sciences report in 2011 predicted that for every degree that the planet warmed there would be a 5 to 15 per cent decrease in overall crop production.

The United Nations Climate Summit held in New York in 2019 set a deadline for achieving zero net emissions by 2050 and reinforced the view that 1.5oC warming was the maximum safe level by the end of the 21st century.