James Rae
@mudwaterclimate.bsky.social
1.9K followers 610 following 94 posts
Climate scientist and geochemist @UnivofStAndrews | CO2 & ocean circulation past & present | Social & Environmental justice
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mudwaterclimate.bsky.social
Hey @bsky.app 👋
I’ll be posting stuff from our group on what we learn from Earth’s past climate that can help us understand where we’re heading - like the geochemical reconstructions below which show that CO2 is at its highest level in 3 million years 📈😬 www.annualreviews.org/doi/abs/10.1...
Long term CO2 reconstruction from my 2021 Annual Reviews paper shows CO2 at its highest level in 3 million years
mudwaterclimate.bsky.social
Sure! And great work @jfarmersalmanac.bsky.social and @oceanandclimate.bsky.social for the fascinating paper and threads!
mudwaterclimate.bsky.social
Kudos to Maddie for leading this work and many thanks to @willerstorfi.bsky.social @gmacgilchrist.bsky.social @oceanicandrea.bsky.social Casimir de Lavergne & Laurie Menviel for all their help and input, @uniofstandrews.bsky.social for funding Maddie’s PhD, and all of you for reading!
mudwaterclimate.bsky.social
We are psyched about this as the ice ages are cool (sorry!) - but also as figuring out these processes by which the ocean took up 100s of gigatonnes of CO2 from the atmosphere in the past may help us better understand the controls on its capacity for carbon uptake in the future… 📈🌊
mudwaterclimate.bsky.social
This likely acted in concert with other processes (changes in winds, circulation, sea ice, iron) to draw down CO2 during the ice ages.
It can also explain why biogeochemical records from the North Pacific and Southern Ocean share similar structure (Haug & Sigman‘s “polar twins” 👯)
Reconstructions of biogeochemistry from the high latitude North Pacific and Southern Oceans share similar structure over the ice ages
mudwaterclimate.bsky.social
Notably, this is achieved without any change in Southern Ocean upwelling, sea ice or iron supply - it’s simply the result of having less carbon in the upwelled water.
Potential CO2 outgassing anomalies in 4 different sets of model simulations with better ventilated intermediate depth North Pacific
mudwaterclimate.bsky.social
The consequence - shown here - is that less CO2 would be delivered to the Southern Ocean. This by itself reduces Southern Ocean CO2 outgassing by as much as 50%.
Outgassing anomaly in the Southern Ocean - less carbon is outgassed due to reduced carbon load of waters upwelled from the Pacific
mudwaterclimate.bsky.social
In previous papers we and others have shown that these intermediate depth N Pacific waters were better ventilated during glacial periods (e.g. figure here from Rae 2020 and see also Rafter 2022 and Keigwin 1998 among others!) www.science.org/doi/full/10....
Figure showing change in different proxies sensitive to ventilation at the LGM relative to today in the North Pacific. Better ventilation is shown by the red dots - and there is a clear signal of this above 2000m.
mudwaterclimate.bsky.social
Part of the inspiration for this study was an interesting paper by Haidi Chen showing that much of the CO2 outgassed in the Southern Ocean today is sourced from the intermediate depth North Pacific. As these waters are old and CO2 rich they have huge outgassing potential (red colours below).
Figure showing ocean outgassing potential - the tendency of a parcel of water to give out CO2 to the atmosphere when it surfaces. Red colours in the North Pacific show its high outgassing potential and these isopycnals outcrop in the Southern Ocean, fuelling regional outgassing.
Reposted by James Rae
earthscista.bsky.social
Big congratulations to @mudwaterclimate.bsky.social & team on securing funding to launch the St Andrews Global Research Centre for Changing Climates! 🌍 📈

The centre will take an interdisciplinary approach, harnessing the breadth of expertise across St Andrews

news.st-andrews.ac.uk/archive/the-...
The University of St Andrews announces two new Global Research Centres | University of St Andrews news
news.st-andrews.ac.uk
mudwaterclimate.bsky.social
Nice one John - see also additional notes in thread below: bsky.app/profile/mudw...
Reposted by James Rae
dpcarrington.bsky.social
ICYM - Scientists slam Trump administration climate report as a ‘farce’ full of misinformation

- Experts say the report being used to justify the mass rollback of climate regulations has many claims based on long-debunked research

#climatecrisis
www.theguardian.com/us-news/2025...
Scientists slam Trump administration climate report as a ‘farce’ full of misinformation
Experts say the report being used to justify the mass rollback of climate regulations has many claims based on long-debunked research
www.theguardian.com
mudwaterclimate.bsky.social
More relevant for fossil fuel CO2 are rapid external carbon additions from large igneous provinces and the organic material they often burn up - consistently linked to mass extinction in the geological record www.nature.com/articles/s41...
Graph showing extinction rate over the past 300 million years and current pH reconstructions. Mass extinctions are consistently associated with ocean acidification.
mudwaterclimate.bsky.social
These sorts of relatively slow reshufflings of carbon around the ocean also aren’t a relevant analogue for very rapid addition of carbon from an external source: in former case saturation state changes are muted, while with FF addition saturation state drops sharply www.science.org/doi/10.1126/...
The Geological Record of Ocean Acidification
As human activity continues to pump nearly 50-fold more CO2 into the atmosphere than any existing natural sources, the oceans absorb it. Over time, this vast quantity of excess oceanic CO2 is expected...
www.science.org
Reposted by James Rae
annackramer.bsky.social
🚨 At least 10 scientists, all cited in the Trump admin's new climate change report, told me that the report completely mischaracterizes their research.

I also found five citations with significant errors, and a paragraph missing an important citation.
‘A Serious Misuse of My Research’: Climate Scientists Say New Trump Energy Report Botches Their Work
“Our work has no relevance,” an astrobiologist whose research was cited in the administration’s climate change report said.
www.notus.org
Reposted by James Rae
rarohde.bsky.social
I've been taking some time to dive into the US EPA's Proposal to revoke the Endangerment Finding related to Greenhouse Gases.

epa.gov/system/files...

They put forth multiple lines of argument about why the current administration believes this should happen.

🧵
epa.gov
mudwaterclimate.bsky.social
Add me to the list! Rae 2018 misrepresented on page 7: we show deep ocean pH rose out of the ice - but surface ocean pH (the more relevant property for the vast majority of marine life) fell!

Please see thread below on catastrophic impact of geological pH change: bsky.app/profile/mudw...
mudwaterclimate.bsky.social
These data demonstrate that ocean acidification is associated with all of the major mass extinctions where we currently have pH reconstructions. The TJ pH drop is similar to possible scenarios in 2100 unless fossil fuel emissions are rapidly reduced. 🐚🌊📉.
Reposted by James Rae
davidho.bsky.social
Motherfucking wind farms…
Reposted by James Rae
hlee.bsky.social
Fascinating paper 👇 not only providing evidence for ocean acidification in the end-Triassic mass extinction, but also wider discussion of the role of reverse weathering in prolonging the effects, and how this changed with the evolution of open ocean calcifying organisms. ⚒️🧪
mudwaterclimate.bsky.social
🚨New paper just out on environmental upset at the Triassic-Jurassic boundary🚨

Using boron isotopes in fossil oysters, we find a major pulse of ocean acidification and CO2 rise, driving global warming and delaying ecosystem recovery following the end-Triassic mass extinction
rdcu.be/ev6XV

🧪🌊⚒️🐚🧵
Journal title in Nature Communications
mudwaterclimate.bsky.social
Finally for anyone needing a boost on climate progress in light of record temperatures and an acidifying ocean, please check out this wonderful article by @billmckibben.bsky.social - the challenge is huge, but so is our progress www.newyorker.com/news/annals-... 🧪💡🔌⚡️☀️
4.6 Billion Years On, the Sun Is Having a Moment
In the past two years, without much notice, solar power has begun to truly transform the world’s energy system.
www.newyorker.com
mudwaterclimate.bsky.social
Not dumb at all - today the open ocean has lots of tiny planktonic carbonate shells that coat the seafloor when they die. This acts as an anti-acid: CO2 addition is part neutralised by dissolving those shells. But they weren’t around yet in the Triassic/Jurassic.
mudwaterclimate.bsky.social
HUGE kudos to fantastic former @earthscista.bsky.social PhD student @mollytrudgill.bsky.social for leading this work, @carbonatefan.bsky.social for ushering us in to the rock record and being generally the best, and an amazing team including several @uniofstandrews.bsky.social BSc/MSc co-authors
mudwaterclimate.bsky.social
These data demonstrate that ocean acidification is associated with all of the major mass extinctions where we currently have pH reconstructions. The TJ pH drop is similar to possible scenarios in 2100 unless fossil fuel emissions are rapidly reduced. 🐚🌊📉.