Redrawing the global warming stripes. In a new paper led by Sebastian Sippel published in Nature today, we show that the early 20th century global ocean surface temperatures and thereby global mean surface temperature were warmer than previously thought. Thread... (1/13) - ThreadSky

retoknutti.bsky.social • 174 days ago

Redrawing the global warming stripes.

In a new paper led by Sebastian Sippel published in Nature today, we show that the early 20th century global ocean surface temperatures and thereby global mean surface temperature were warmer than previously thought.

Thread... (1/13)

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brucettcalvert.bsky.social•174 days ago

I'm glad this paper is now published. I have been looking forward to reading it. I hope the paper encourages more research in sea surface temperature biases.

anlomedad.bsky.social•173 days ago

Most interesting! Thank you. I sometimes consult EN4 Atlantic data by UKMetOffice and started discarding everything before 1960 when that earlier data turned out too confusing in answering the various questions I use EN4 for. Glad to see my choice justified by your surprising study.

retoknutti.bsky.social•174 days ago

Full paper: https://www.nature.com/articles/s41586-024-08230-1

It’s probably the most iconic time series in climate change and the basis for the iconic warming stripes: global temperature (GMST) since ~1850. (2/13)

retoknutti.bsky.social•174 days ago

And while observations are of very high quality after WWII, the early 20th century remains a puzzle due to sparse coverage and changing measurement sources and instruments. (3/13)

retoknutti.bsky.social•174 days ago

We show that quantifying GMST from ocean-only data indicate lower temperatures 1900-1930 than reconstructing from land-only data, despite all known and fixed issues with measurement practice. (4/13)

retoknutti.bsky.social•174 days ago

While short-term variability agrees very well, the long-term deviations are so large (more than 0.2°C) that they cannot be explained by natural unforced variability or a response to forcing. (5/13)

retoknutti.bsky.social•174 days ago

The large and implausible land-ocean contrast is also seen if only coastal stations are considered, and the ocean cold anomaly is not as pronounced in paleoclimate reconstructions. (6/13)

retoknutti.bsky.social•174 days ago

The too pronounced ocean cold anomaly in the early 20th century thus leads to ocean cooling in the period 1871-1910, and very fast warming 1901-1940, both of which is inconsistent with the reconstructions based on global land temperatures, physical understanding, all climate models, and (7/13)

ryankatzrosene.bsky.social•173 days ago

Would actually be cool to see the warming stripes comparison pre- and post- addendum.

Not sure if you know this, but over on the other site there are lukewarmers referring to this paper as "a bombshell" revelation about warmer 20th century that the media doesn't want to discuss 🙄

retoknutti.bsky.social•173 days ago

If the goal was to hide something, then one would probalby not publish it in Nature…

gillesh38.bsky.social•167 days ago

aren't most proxies calibrated on this period ?

alansmithest.bsky.social•174 days ago

I worked with NODC SD2 in the early 1990s and the pre-WWII coverage especially in the SH and south central Pacific was incredibly sparse. Individual ship tracks were readily apparent. Good to see more research into ocean observations from before 1940.

ozhillbilly.bsky.social•174 days ago

Nice paper.

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