It’s official: 2015 was the hottest year ever recorded, by a huge margin. The world is 0.75°C hotter than the long-term average, and 1°C hotter than it was before people started burning fossil fuels on an industrial scale.
This is according to data sets released on Wednesday by the United Kingdom’s Met Office, the National Oceanic and Atmospheric Administration in the United States, and Nasa. They gave credence to what daily temperature records and altered weather patterns have been signalling – that 2015 took the previous record set by 2014 and broke it.
The margin by which 2015 beat the previous year has been flagged by the three agencies as cause for great concern; 2014 was 0.57°C hotter than the long-term average for the planet, and 2015 was 0.75°C hotter. Even in the midst of climate change the increase between years is normally smaller than this. That 2015 was so much hotter than it should have been had a lot to do with the effect of the most powerful El Niño ever recorded. The phenomenon warms the Pacific Ocean and brings about hotter weather worldwide.
This dovetailed with long-term warming to bring torrential rainfall and a hot Christmas to the northern hemisphere. The UK was, on average, 10°C hotter this December than it usually is. Instead of snow, several countries experienced flooding as the warm air drove the rainfall.
In the southern hemisphere, El Niño has meant drought and extreme heat. In South Africa, temperatures consistently headed into the high 30s and low 40s, when they should have been in the low 30s.
In October, Vredendal, near Cape Town, set a global temperature record for that day by hitting 48.4°C, which so alarmed the South African Weather Service that it rechecked the town’s measuring instruments.
Worldwide, January and April were the only months of 2015 that did not break their own monthly records. Since the year 2000, average global monthly temperature records have been broken more than 30 times. World War I had just started when the previous average monthly cold record was broken.
In South Africa, recent lower temperatures and rain have brought relief, but the weather service gives a sobering projection for 2016: “Drier and warmer conditions are expected to be extreme … and may worsen the current drought conditions.”
The UK Met Office says 2016 will beat 2015’s record, creating the hottest consecutive years on record.
Those records mean that the world is, on average, 1°C hotter than it was before the Industrial Revolution. That moment coupled the burning of fossil fuels to economic growth, a relationship that is only now starting to uncouple. The Paris Agreement, accepted by world governments at COP21 last year, set a goal of ensuring average temperatures do not increase by another 1°C this century. But environment watchdogs say the sum total of countries’ pledges will see the world warm by an average of 3°C this century. This will lead to irreversible climate change, says the UN Framework Convention on Climate Change.