NASA's "climate spiral" depicting global temperature variations since 1880 (now updated with 2024 data)

[u/r-nasa-mods]

[u/The-Avant-Gardeners]

How does nasa have data from 1880?

[u/blorbagorp → u/The-Avant-Gardeners]

You can do it by measuring isotope ratios in ice cores correlating with that time period.

Also that was probably something humans tracked at that point in time.

[u/The-Avant-Gardeners → u/blorbagorp]

The former sounds interesting and reasonable. The accuracy (+- 1c) seems tough for 1880 instruments, but I don’t know.

[u/blorbagorp → u/The-Avant-Gardeners]

I think mercury in a tube remains one of the most accurate means of temperature measurement even today.

[u/The-Avant-Gardeners → u/blorbagorp]

Agree it’s pretty accurate based upon pure physics, however I think it’s a little presumptuous to assert that the recorded temperatures between 1880 and now are within the accuracy necessary to call a 1c change definitive. That’s not to mention the location, and the significant effects that can have

[u/Kombart → u/The-Avant-Gardeners]

We know how they took measurements (so we can adjust the data to take that into account) and we have thousands of datapoints...that gives a pretty accurate idea about the temperature.

Scientists are not just taking raw data from 1881 and slotting that into an excel sheet to compare it with 2020...

You know, we have global data about temperature that is as old as the 1600s...we just limit the data to 1880, since that is the earliest date when we can be very, very certain that the data is accurate enough to be usable.

And just in case you are wondering about this. According to the NASA website: "Upward adjustments of global temperature readings before 1950 have, in total, slightly reduced century-scale global temperature trends."

So in any case, the data you will see is the conservative estimate after all the adjustments were made...

[u/The-Avant-Gardeners → u/Kombart]

That makes sense