Global warming accelerates
The last time a year broke the average cold record, shells were whistling over fields in France and crunching into trenches. World War I had just begun. Since then, the world has got steadily warmer for eight decades. This was predictable climate change, but in the last handful of years temperatures have increased at a dizzying rate. Average heat records are tumbling every month — last month the world was 1.35°C hotter than average.
The science behind this is unequivocal. To industrialise, humans have pumped huge amounts of greenhouse gases into the atmosphere. Known as carbon emissions, these stay in the atmosphere and trap heat that would otherwise head out into space. Nearly all of this heat is trapped in the oceans. Given their size, these only gradually change temperature — a mere 100th of a degree every decade is normal. But this rapidly changes when El Niño warms the Pacific Ocean by three degrees in a short space of time. This phenomenon happens every six or so years, creating wetter weather in the northern hemisphere, and drought in the southern hemisphere.
El Niño has coincided with several other phenomena that rapidly warm the planet. In the noughties, decreased solar and volcanic activity slowed the rate of warming. But in the last five years temperatures have increased dramatically. Previously, record hot years were a once-a-century thing. When 1998 broke records, thanks to an El Niño that year, it was a normal occurrence. But then 2005 broke that record, as did 2010, 2014 and 2015. The rate of this record breaking has accelerated, especially when combined with El Niño. While 2014 was 0.5°C hotter than the 20th century average — the temperature it would have been without humans burning fossil fuels — the following year was 0.75°C hotter than average.
Policymakers met at the 21st Congress of the Parties in Paris (COP 21) late in 2015, a year into the southern hemisphere’s drought, and agreed to limit the warming. The resulting Paris Agreement requires that countries work to limit global warming to an average of 2°C. This is the level at which the UN’s climate body, the Framework Convention on Climate Change, says warming becomes “dangerous” and “irreversible” if passed.
In South Africa, the Council for Scientific and Industrial Research says this warming translates to a 6°C increase in temperatures in the highveld. At that level, rainfall becomes too random to support intensive agriculture.
The Paris Agreement also included an aspirational goal of limiting warming to 1.5°C this century. This was a clause demanded by island states and countries in the tropics, which will suffer disproportionately from global warming and struggle with the changes the first world’s pollution creates. Most of these are developing countries, so they do not have the money and government structures to deal with catastrophes. They also have little recovery capacity, as previous disasters have often already wiped out their savings and infrastructure.
But the agreement came in a month that shattered all previous temperature records. The north pole was an average of 0°C in December, 30°C hotter than usual. January then upped the ante by becoming the hottest month in history, by the greatest margin in history. Data from Nasa in the US shows that February continued this warming, pushing temperatures to 1.35°C above average. In early March the northern hemisphere passed a symbolic mark, hitting an average of 2°C hotter than normal. With El Niño only starting to dissipate, this warming is predicted to continue until winter.
Global warming has accelerated, giving a taste of what is to come: droughts, floods and food insecurity are projected to become the norm. Clever solutions are urgently required.