Copernicus records first June breach of 1.5°C climate threshold

First June breach of 1.5°C limit

The global-mean surface air temperature was more than 1.5°C above pre-industrial levels in early June, which is a first for a summer month, the EU-funded Copernicus Climate Change Service (C3S) implemented by ECMWF has said.

Global temperatures higher than 1.5°C above pre-industrial levels have been observed before, but until now only in northern hemisphere winter and spring months.

The Copernicus finding is based on ECMWF’s ERA5 climate reanalysis data record for early June.

The Paris Agreement on climate change, which came into force in 2016, says efforts will be pursued to limit the long-term rise of temperatures to 1.5°C above pre-industrial levels.

First June breach of 1.5°C limit

The charts show (a) global-mean temperature (⁰C) averaged for each day of ERA5 from 1 January 1940 to 11 June 2023, plotted as time series for each year, with years from 2015 onwards distinguished by colour. The dashed and dotted lines denote values that are respectively 1.5⁰C and 2⁰C above the 1850­–1900 reference values taken to represent pre-industrial levels. (b) Global-mean temperatures for 2016, 2020 and parts of 2015 and 2023 expressed as differences (⁰C) from 1850–1900 levels. (Source: C3S)

Previous instances

Although the 1.5°C limit has now been surpassed in June, this is not the first time that the daily global average temperature rise has been above 1.5°C.

This threshold was first exceeded in December 2015, and then repeatedly in the northern hemisphere winters and springs of 2016 and 2020.

The 1.5°C limit established by the Paris Agreement has not yet been surpassed as it was set for changes in twenty- or thirty-year averages, not for brief periods of time such as daily or monthly anomalies.

Rising trend

In May, the World Meteorological Organization (WMO) published a report highlighting a 66% likelihood that the annual average global temperature in 20232027 would be more than 1.5°C above pre-industrial levels for at least one year.

As El Niño continues to develop, there is good reason to expect periods in the coming twelve months during which the global-mean air temperature again exceeds pre-industrial levels by more than 1.5⁰C.

According to the WMO report mentioned above, there is a 98% likelihood that at least one of the next five years, and the five-year period as a whole, will be the warmest on record.

There is also a 32% chance that the five-year mean will exceed the 1.5°C threshold set in the Paris Agreement.

More details can be found on the C3S website.