Climate Lab Book

With instrumentation across the globe at naval timekeeping stations of the various European empires - much of which persisted for a hundred years and thus overlapped with later instruments and broader coverage which allowed for levelling and blending.

It's essentially a "construct your baseline" problem faced in many domains, the Fifth and other IPCC reports:

This IPCC Special Report on Global Warming of 1.5°C uses the reference period 1850–1900 to represent pre-industrial temperature. This is the earliest period with near-global observations and is the reference period used as an approximation of preindustrial temperatures in the IPCC Fifth Assessment Report. ~ IPCC FAQ: https://www.ipcc.ch/site/assets/uploads/sites/2/2018/12/SR15_FAQ_Low_Res.pdf and naturally there are many papers that consider alternate baselines, data quality, proxies, etc. eg:

Estimating Changes in Global Temperature since the Preindustrial Period (2017)

https://journals.ametsoc.org/view/journals/bams/98/9/bams-d-16-0007.1.xml

^^ Discussed in brief: https://www.climate-lab-book.ac.uk/2017/defining-pre-industrial/

"Using this kind of graph one can more easily see"
False, I cannot tell what is happening in this graph.

It's hard to go back and forth between the graph and the legend to tell what year it is. One way to improve the readability is to have the color shift uniformly between one PAST color and one PRESENT color so I can follow the line from the past to the present.

While animation rarely improves graphs, it really can if time is the 3rd dimension your 2d visualization (image) needs. Something like this
http://www.climate-lab-book.ac.uk/spirals/
(first gif)

Back-of-the-envelope calculation: https://www.climate-lab-book.ac.uk/2015/back-of-the-envelope-attribution/

The TCR needs some explanation, but can be estimated from the Stefan-Boltzmann law; the temperature differential to produce a radiative output of 3.7 W/sq m is 3.7 / (4 * sigma * T0^3) which at a T0 of 287 K is 0.69 K. Clearly the Earth is not a perfect black-body so this lower bounds the TCR.

This also allows us to lower bound the anthrogenic climate contribution due to GHG radiative forcing 1850-2020 at 0.48 K.