Dr Zeke Hausfather is a climate scientist and energy systems analyst whose research focuses on observational temperature records, climate models, and mitigation technologies.
By Dr Zeke Hausfather
This year is shaping up to be one of top four warmest years on record – and has a modest chance of being the warmest on record.
Exceptionally warm conditions are being driven by the end of a persistent triple-dip La Niña and a rapid transition into warmer El Niño conditions.
Taking the first three months of the year, global surface temperatures so far are tied as the fourth warmest on record, after 2016, 2020 and 2017.
March 2023 was the second warmest since records began in the mid-1800s, with record warm temperatures in parts of central Asia, coastal China, and Japan, as well as South America.
Global surface temperature anomalies for March 2023 compared to a 1951-1980 baseline period, taken from Berkeley Earth.
Based on the year-to-date and the current El Niño forecast, Carbon Brief estimates that 2023 is very likely to end up between the warmest year on record and the sixth warmest, with a best estimate of fourth warmest. So early in the year, it is difficult to precisely predict where annual temperatures will end up.
Arctic sea ice extent is currently on the low end of its historical range, while Antarctic sea ice set new all-time low records in the first two months of 2023, with an all-time low summer minimum for the Southern Hemisphere in February 2023.
Fourth warmest start to a year
Global surface temperatures are recorded and reported by a number of different international groups, including NASA, NOAA, Met Office Hadley Centre/UEA and Berkeley Earth. Copernicus/ECMWF also produces a surface temperature estimate based on a combination of measurements and a weather model – an approach known as “reanalysis”.
The chart below compares the annual global surface temperatures from these different groups since 1970 – or 1979 in the case of Copernicus/ECMWF. The coloured lines show the temperature for each year, while the dots on the right-hand side show the year-to-date estimate for January to March 2023.
Values are shown relative to a common baseline period – the 1981-2010 average temperature for each series. Surface temperature records have shown around 1C warming since the year 1970, a warming rate of about 0.19C per decade.
Locations setting record warm temperatures in the first three months of 2023 based on data back to 1850, taken from Berkeley Earth.
Year-to-date values are only shown for NASA, NOAA, Berkeley, and Copernicus as data for March is not yet available from Hadley/UAE. The year-to-date values will be updated when the data becomes available.
The temperatures in the first three months of 2023 were fairly warm, with year-to-date values in some records (NASA, Berkeley, NOAA) roughly tied with the warmest annual temperature anomaly on record.
However, higher temperature anomalies tend to occur in the early part of the year, so year-to-date temperatures may be somewhat higher than annual temperatures in some of the records.
The figure below shows how temperatures to-date in 2023 compare to prior years in the NASA dataset. It shows the temperature of the year-to-date for each month of the year, from January through to the full annual average.
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