March 2021 Temperature Update

The following is a summary of global temperature conditions in Berkeley Earth’s analysis of March 2021.

  • March 2021 was the 9th warmest March since records began in 1850.
  • Very warm conditions occurred over parts of North America, Asia, and the Middle East.
  • Weak La Niña conditions were present in March and are expected to end soon.
  • The effect of the La Nina during early 2021 is likely to keep this year cooler than other recent years.
  • Based on the first three months, this year is currently positioned to be around the 7th warmest year overall, with only a negligible chance of it being a top 3 warmest year.

Global Summary

Globally, March 2021 has been the ninth warmest March since records began in 1850. This is similar to some other recent years, including 2018 and 2015, but appreciably cooler than in 2019 and 2020.

The global mean temperature in March 2021 was 0.86 ± 0.05 °C (1.55 ± 0.09 °F) above the 1951 to 1980 average.

This is equivalent to being 1.19 ± 0.07 °C (2.14 ± 0.13 °F) above the 1850 to 1900 average, which is frequently used as a benchmark for the preindustrial period.

The global mean temperature anomaly in March 2021 was similar to that in January 2021, but sharply warmer than in February 2021. Temperatures in March are somewhat below the long-term trend line but consistent with natural variability, and in particular the La Niña conditions in the Pacific.

Spatial Variation

March 2021 continues the ongoing pattern of wide-spread warmth, though with some notable exceptions. Particularly warm conditions were present in parts of North America, Eastern Asia, and the Middle East. Record setting warmth was also present in parts of Antarctica. In addition, an unusually large area of warm water was present in the Western Pacific Ocean. Significantly cool temperatures occurred in Northern Asia, and the Eastern Pacific.

The cool temperatures in North Central Asia contrast strongly with the record-breaking conditions present in that region during 2020.

We estimate that 2.1% of the Earth’s surface experienced their locally warmest March average, and 68% of the Earth’s surface was significantly warmer when compared to their local average during the period 1951 to 1980. In addition, no place on Earth’s surface had their locally coldest March.

The cool area in the Eastern Pacific, first observed in June 2020, is significantly less well organized than in previous reports, though we would consider its presence to be a continuing effect of La Niña conditions. This La Niña state has contributed to the relatively cool global averages thus far during 2021.

Over land regions, 2021 was the 11th warmest March, coming in as 1.42 ± 0.12 °C (2.55 ± 0.20 °F) above the 1951 to 1980 average.

Influenced by La Niña, March 2021 was the 10th warmest March in the oceans, recorded as 0.52 ± 0.04 °C (0.94 ± 0.06 °F) above the 1951 to 1980 average.

2021 January to March Summary

After 3 months, the Earth in 2021 has been marked by above average temperatures in most areas, with the notably exceptions on the tropical Eastern Pacific and Northern Asia. Northern North America and mid-latitude Asia experienced some of the most pronounced warmth on land, while ocean temperature records were present in parts of the North, South, and Western Pacific. We estimate that the January to March average has been record warm for 3.7% of the Earth, and appreciably above the 1951 to 1980 average for 71% of the Earth. Only, 6.3% of the Earth’s surface was significantly cooler than the 1951 to 1980 average during the current January to March period, and no locations were record cool.

Looking at regions where January to March temperature averages were either the top 5 warmest or the top 5 coldest observed, we note significant regions with record or near-record warmth during the first three months of 2021 and almost no regions of near-record cold.

La Niña

March 2021 showed fading La Niña conditions in the Pacific Ocean with a less organized pattern of cool water. These conditions are near a return to normal. Research groups have a divided opinion on whether La Niña has already ended. The CPC/IRI analysis, which we generally favor, considers La Niña to have weakened but still be weakly present during March. By contrast, the Australian Bureau of Meteorology has taken the position that La Niña is already over.

The La Niña conditions which have occurred during the last several months are expected to reduce global mean temperature during the first half of 2021, and make it very unlikely that 2021 will be a record warm year. Most models expect neutral conditions during the rest of 2021, with a return to El Niño not considered likely.

History of sea surface temperatures in the core ENSO region from IRI/CPC.

Rest of 2021

The La Niña event of late 2020 and early 2021 makes it likely that 2021 will be cooler than other recent years, though it is nearly certain to remain within the top ten warmest years overall. The La Niña is expected to end soon, but the impact on global mean temperature will likely persist for several additional months. The annual average might be expected to warm some during the latter half of 2021 compared to March, but the full year is unlikely to challenge the previous record warm years.

The statistical approach that we use, looking at conditions in March and prior months, believes that 2021 is most likely to be the 7th warmest year in the instrumental record, with some chance of being the 5th or 6th warmest. It is unlikely that 2021 would be any colder than 7th warmest, which means that it is very likely to still surpass all years prior to 2015. The odds of setting a new record warm year in 2021 are negligible.

Likelihood of final 2021 ranking, based on January 2021:

  • 1st place (<1%)
    • Top 3 overall (<1%)
  • 4th place (6%)
  • 5th place (16%)
  • 6th place (18%)
  • 7th place (56%)
    • Top 7 overall (97%)

HadSST4

The current report marks the second of our reports to transition to HadSST4 rather than HadSST3.

This new version of the sea surface temperature data set produced by the UK Met Office / Hadley Centre includes a number of significant improvements. Most notable are adjustments to uncertainty during the World War II period and corrections related to the transition from ships to automated buoys as the primary means of measuring sea surface temperature.

From this point forward, Berkeley Earth’s Land and Ocean data set will utilize HadSST4. This transition does not require any change in our analysis methods, though the empirically-determined interpolation parameters were recalculated for the new data set. Overall the results of the two data sets are very similar, with the HadSST4 version resulting in a very slightly higher global warming trend than its predecessor.

The effect of this transition will be explored in more detail in a forthcoming discussion.

However, we note that delays in the availability of HadSST (both 3 and 4) have been responsible for delays in updating Berkeley Earth’s temperature data set. It is our hope and expectation that these delays will be resolved soon.

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