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When will the global annual mean surface air temperature moving average first exceed 1.3°C relative to the 1951-1980 base period?

Surface air temperature change is a primary measure of global climate change. The globally averaged combined land and ocean surface temperature data as calculated by a linear trend, show a warming of 0.85°C (90% CI: [0.65 to 1.06]), over the period 1880 to 2012 (IPCC, 2013). The effects of increased global surface temperatures, and the associated changes in climate include:

  • Increases in the frequency and intensity of intense precipitation (Min et al., 2011), and increases in the proportion of the global land surface in extreme drought (Burke et al., 2006),
  • Global sea level rise (Vermeer and Rahmstorf), which in turn may result in the erosion of beaches and coastal wetlands, increased flooding, and intrusion of saltwater into rivers, bays, and aquifers (Titus, 2008), and global ocean warming and acidification (Pörtner, 2008),
  • Adverse effects to human health, due to thermal stress, and the increased prevalence of infectious diseases (McMichael et al., 2006), and increased food security risk (Zhao et al., 2017; FAO, 2008),
  • Loss of terrestrial biodiversity at all system levels, including species-level reductions in range size and abundance, especially amongst endemic species (Warren et al., 2013).

According to GISS Surface Temperature Analysis data, over the 2008 to 2018 period, the mean surface air temperature was 0.76°C higher relative to the 1951 to 1980 baseline. 2016 was the hottest recorded year with the mean surface temperature being 1.02°C higher than that over the same baseline.

In 2017, the 3-year simple moving average of the increase in temperature relative to the 1951-1980 base period reached the highest level at 0.95°C. This means that it was on average 0.95°C hotter over the 2015 to 2017 period (inclusive) relative to the base period.

When will the global annual mean surface air temperature moving average first exceed 1.3°C relative to the 1951-1980 base period?


This question resolves as the first year when the 3-year moving average of the change in global annual mean surface air is 1.31°C or higher. The question resolves as January 1st of the year in which this first happens. This data must be by GISS Surface Temperature Analysis, with the 1951-1980 base period. The adoption of this base period amounts to scaling reported temperature changes such that the mean temperature change over the 1951-1980 period is 0.


GISTEMP v4 data may be accessed here, and the associated moving averages. Data can also be found here. Please make a copy by clicking "file" and then "make a copy" if you wish to edit it. If you make useful additions to the dataset, please share the file in the comments.


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