Hi Paul, your comment that we've already exceeded 1.5℃ at least temporarily is central to the concept of the Overshoot Era.
I have been analysing data on global mean surface temperature since 1940 from the database at the European Centre for Medium-Range Weather Forecasts, in order to visualise and calculate various scenarios for the dates when the planet crosses 1.5 and 2 degree thresholds.
It is possible to use this data to compare a range of simple models in an Excel spreadsheet chart.
For example, setting the start and end dates of the scenario , and setting the trend calculation as linear, quadratic or a higher polynomial, gives highly distinct results. The standard statistical method of least-squares regression is now readily accessible through AI, allowing anyone to calculate and compare trend equations without specialist statistical software or expertise. Comparing scenarios validates the acceleration seen in quadratic trends and shows that linear trend scenarios that ignore acceleration have a weak fit to recent data. Using a fourth order polynomial emphasises the rapid recent acceleration even more and brings forward the 1.5 trend crossing point.
Using a quadratic trend line, starting from 1980 and including data up to May 2026, gives a 1.5C crossing date of 19 May 2026. On that basis we are now permanently in the Overshoot Era, at least until SRM cools the Earth. This same quadratic trend curve give a 2C crossing date of 16 July 2037.
Love this!!
Good timing Paul. Have you seen the new UNEP report "Limiting Overshoot" - published today.... https://wedocs.unep.org/items/156d074c-ab1d-4833-acf8-6343589ede9b
Thanks Janos, I did see that and look forward to reading it. I really think Overshoot is going to become a dominant narrative in the near future.
Hi Paul, your comment that we've already exceeded 1.5℃ at least temporarily is central to the concept of the Overshoot Era.
I have been analysing data on global mean surface temperature since 1940 from the database at the European Centre for Medium-Range Weather Forecasts, in order to visualise and calculate various scenarios for the dates when the planet crosses 1.5 and 2 degree thresholds.
It is possible to use this data to compare a range of simple models in an Excel spreadsheet chart.
For example, setting the start and end dates of the scenario , and setting the trend calculation as linear, quadratic or a higher polynomial, gives highly distinct results. The standard statistical method of least-squares regression is now readily accessible through AI, allowing anyone to calculate and compare trend equations without specialist statistical software or expertise. Comparing scenarios validates the acceleration seen in quadratic trends and shows that linear trend scenarios that ignore acceleration have a weak fit to recent data. Using a fourth order polynomial emphasises the rapid recent acceleration even more and brings forward the 1.5 trend crossing point.
Using a quadratic trend line, starting from 1980 and including data up to May 2026, gives a 1.5C crossing date of 19 May 2026. On that basis we are now permanently in the Overshoot Era, at least until SRM cools the Earth. This same quadratic trend curve give a 2C crossing date of 16 July 2037.
I call it "Project Lameshot" as we "lamedown" refusing to enhance albedo.
https://www.science.org/doi/10.1126/sciadv.aee9228?utm_source=cbnewsletter&utm_medium=email&utm_term=2026-09-03&utm_campaign=Daily+Briefing+El+Ni%C3%B1o+strongest+for+70+years+China+emissions+fall+Heathrow+risk+
Appropriate name for the times. The fallacy of overshoot plans is p'ing in the wind and expecting to stay dry.