We know all about how the Earth's temperature needs to stay below "1.5° above pre-industrial levels". But what were they?

Every news article and policy statement seems to hand-wave it away. Graphs put the 1880 temperature at zero. But 1880 was not zero, it had a temperature. And so does today. And so will tomorrow. What was it? What is it? What will we need it to be?

I'm not asking for just a methodology or an abstraction here. I want a number.

  • $\begingroup$ I think 1.5 °C above average temperature in the years 1850-1900. $\endgroup$
    – Lehs
    Nov 13, 2021 at 11:18

1 Answer 1


According to NOAA

Averaged across land and ocean, the 2020 surface temperature was 1.76° F (0.98° Celsius) warmer than the twentieth-century average of 57.0°F (13.9°C) and 2.14°F (1.19°C) warmer than the pre-industrial period (1880-1900).

Simply do the math. The 2020 global surface temperature was 1.76°F warmer than 57.0°F, which is 58.76°F. This temperature is 2.14°F warmer than the pre-industrial period (1880-1900). Consequently, the pre-industrial period temperature was 58.76°F - 2.14°F, or approximately 56.62°F (13.68°C).


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