STATUS: DRAFT – NOT READY YET – 3rd Oct 2026

This page is under construction and has placeholder text and placeholder images –

Given that analyses show that we are crossing 1.5C global warming, I wondered what the upcoming
2028 IPCC “Assessment Report 7” (AR7) Report might say.

I thought I would look back at the previous IPCC Assessment Reports (AR2 -> AR6), and compare these
to the global warming data from popular datasets. Given that high profile authorities have given estimates for 2026 and 2027, I wondered if this would lead me to a reasonable guesstimate for the Global Warming figures to be published in AR7.

I have used global Warming Datasets: Copernicus ERA5, Nasa GISS, NOAA, Berkeley Earth, Met HadCRUT, and plotted the yearly global warming anomalies, and the Loess-30-year-trend for each data set. For the future data I have assumed 2026 will be the same as 2024, and 2027 will be 0.15C warmer than 2024.

Conclusions

  • When the IPCC publishes the central global warming value in an Assessment report, it is over 10 years behind the current reality
  • When the IPCC publishes gives hints about how fast it thinks we are warming, it will likely be shown to be an underestimate within a few years.
  • My guesstimate (assuming they use the same methods): IPCC AR7 will say we are around ~1.35C warming at ~0.26C/Decade
  • The concept of this graph, was much more fun to come up with, than going through all the steps to actually create it, verify the data sufficiently (including irritation about Berkeley Earth appearing to keep changing how cold they think it was in pre-industrial times), finding that there is more subjectivity to this than I originally expected, and writing up the methodology. I should revisit my life choices regarding the amount of effort I put in. Please read more about what the graphic means, and what decisions were made before giving any feedback.

How the Graph was created and what it means

I have taken the Global Warming values from the IPCC Assessment Reports. taking the Global Warming value and range,
the dates, over which that range was based, and the warming rate

Example – AR6

IPCC AR6 WG1 SPM pg5:
    “Global surface temperature was 1.09 [0.95 to 1.20] °C higher in 2011–2020 than 1850–1900”
    … and some values we can use to determine the IPCC’s view on warming rage:
   “estimated increase in global surface temperature since AR5 is principally due to further warming

   since 2003–2012 (+0.19 [0.16 to 0.22] °C”

As above, I have plotted this as:

  • Date Range: 2011-2020 (inclusive), with Cenrtal Date: 2015
  • Anomaly Range: 0.95 -> 1.2, with Central 1.09
  • Central Date, Central Anomaly
  • Warming Rate Implied global warming at publication

Example – IPCC AR2

For IPCC Assessment Reports 2 and 3 (AR2 and AR3), They have a different format, so it a bit hard to know how
to plot this in a fair way.



If I were to use the same shapes
As I have for AR4,AR5,AR6,AR7
then what date range do I use?

Should I assume that they mean
the 20 years  before publication?
…and therefore plot the central date
as being 10 years earlier

With the warming rate, should I plot linear warming from 1850-1900 … to give an implied warming at the time of publication.

I just decided to keep it simple, and have a vertical line. This does make it look like AR2 and AR3 are particularly low.
If I had assumed 20-years, then they would still be low, but not quite as bad

Data Sanity Checks – Copernicus

TODO

References

TODO