Last week, global temperatures appeared to momentarily breach a threshold set by world governments to try and avoid widespread climate devastation.
On November 17 and 18, the world was, on average, 2 degrees Celsius warmer than pre-industrial levels for the first time in modern recorded history.
The pre-industrial period was a time before widespread fossil fuel use.
Burning fossil fuels has pumped substances like carbon dioxide (CO2) into the atmosphere, trapping heat at the planet’s surface as part of the greenhouse effect.
The world’s governments came up with the Paris Agreement in 2015 to keep global average warming to well below 2C, and ideally lower than 1.5C.
Breaching the 2C threshold for a few days is not the end of the world, experts say, but it is just another sign of how much the planet is warming.
And it comes at a time when countries are preparing to meet at the United Nation’s 28th Climate Change Conference (COP28) to discuss fossil fuel reduction.
A complex topic when coal production is expected to increase to 2030, and oil and gas production to 2050 and beyond.
How do we know we went over 2C?
The figure was calculated by the European Centre for Medium-Range Weather Forecasts through one of its observational programmes, the Copernicus Climate Change Service.
The service uses a model, known as ERA5, which provides hourly estimates of atmospheric, land and ocean data from 1940 to the present.
The centre came up with the 2C figure by comparing last week’s surface air temperatures from ERA5 to those from 1850 to 1900.
Although international agreements refer to “pre-industrial” temperatures, there is no agreement on the exact period this covers.
But the UN’s Intergovernmental Panel on Climate Change (IPCC), which is the leading body for informing international climate policy, has used 1850 to 1900 as a baseline for its reports.
