baseline lie

The Global Temperature Baseline Lie

Like the “Fridays for Future” movement or “Green New Deal” the Paris Agreement has already called for a limitation of global warming to well below 2 °C above preindustrial levels; and to limit the increase to 1.5 °C.

Searching for current data you’ll find it for example at NASA , a U.S. agency. The last mean temperature anomaly from 2018 is +0.8 °C. These data are often used in publications and suggest that we still have plenty of room for +2°C.

So everything’s all right?

global temperature

The blue curve shows the global annual mean temperature anomalies. For the baseline, the zero mark, an average of temperature anomalies is taken from 1951 to 1980. You can speculate what the reason for choosing the baseline is.

But Paris demanded the limitation over preindustrial levels.

Additional adjustment of the data is needed, in order to reflect a 1750 baseline. The total baseline adjustment could add up to as much as 0.55°C … a lack of measurements in the Arctic that go back to 1900. Simply excluding those data would downplay the temperature rise, since temperatures have been rising faster in the Arctic than in the rest of the world. An additional adjustment of 0.1°C therefore seems appropriate. … To get an idea how much the temperature of the atmosphere has risen close to the surface, it makes more sense to use air surface temperature over oceans, rather than sea surface water temperatures, resulting in another additional adjustment of 0.1°C. The total adjustment adds up to 0.75°C.

Sam Carana, Feb 2019

The red curve reflects this adjustment.

In 2018 we had a global temperature 1.57 °C above preindustrial levels. In the strong El Nino year 2016 we have hit the mark of +1.7 °C. The polinomial trend line is near 1.7 °C.

The global temperature will follow the CO2 concentration for decades.

CO2 and global temperature

The limitation of the global temperature rise to +2 °C seems impossible.

Please also note: It is Too Late to Prevent Climate Change


FTE38 ~ AS IF – One Year to Live – Part 6


It is Too Late to Prevent Climate Change


  1. Moving the baseline date is the new climate denial position. 1750 is the absolute latest date that should be used.
    Thomas Savery had a coal fired steam pump operating at the turn of the century, why would we ignore that warming and carbon?

  2. Wolfgang

    In April 2019 Sam Carana wrote that “2019 could be 1.85°C warmer than preindustrial”. We could reach +3°C in 2025 (long term trend) or even faster in 2020.

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