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Bruce Calvert

@brucettcalvert.bsky.social
95 followers 34 following 215 posts

Interested in temperature statistics and datasets.

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Reposted by Bruce Calvert
Tim Osborn @timosbornclim.bsky.social · 23/09/2026
New version of the HadCRUT global temperature dataset released @colinmorice.bsky.social HadCRUT5.2 uses HadSST4.2 (with improved adjustments for SST biases during 1933-1961) and CRUTEM5.2 (with updates to stations in China, USA and Canada). Here is the difference from the previous version 5.1
Alt text: Timeseries from 1850 to 2026 of global average temperature from HadCRUT versions 5.1 and 5.2 and their difference.
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Bruce Calvert @brucettcalvert.bsky.social · 25/09/2026
Thanks, I suppose this use of Jakarta and Chile data allows the SOI to be somewhat reliable for 1866-1875.
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Bruce Calvert @brucettcalvert.bsky.social · 25/09/2026
Are there homogeneity adjustments or something similar for the pre1876 CRU estimates, or should I instead view this time period as substantially less certain than the following decade?
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Bruce Calvert @brucettcalvert.bsky.social · 25/09/2026
The Australian Bureau of Meteorology SOI only goes back to 1876. What allows you to extend this back further? Also the linked CRU webpage says that Darwin and Tahiti pressure data goes back to 1855. So why stop at 1866?
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Reposted by Bruce Calvert
Tim Osborn @timosbornclim.bsky.social · 24/09/2026
I’ve updated the long-running (starts 1866) CRU Southern Oscillation Index (SOI). This lets us compare the currently developing El Niño with earlier events including 1877-78. 2026 has developed very quickly, similar to the 1997-98 one. Thick line is 3-month running mean, with y-axis reversed.
1866-present timeseries of Climatic Research Unit SOI with some major El Niño events marked.
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Reposted by Bruce Calvert
Berkeley Earth @berkeleyearth.org · 02/09/2026
News we could not be more excited to share: the description paper of our high-resolution dataset is now available for review and comment at ESSD. The record provides global coverage at 0.25° resolution, built from 58,311 weather stations extending back to 1750. Pre-print: tinyurl.com/9dw7jbnf
tinyurl.com
Berkeley Earth Surface Temperature – High-Resolution (BEST-HR): a 0.25° Global Gridded Temperature Data Set for Climate Monitoring
Abstract. We present version 2 of the Berkeley Earth Surface Temperature dataset, a global observational temperature record that now features enhanced spatial resolution (0.25° × 0.25°) and a new regr...
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Reposted by Bruce Calvert
Bruce Calvert @brucettcalvert.bsky.social · 01/09/2026
The Berkeley Earth version 2 paper is now in preprint. The new version is 0.25° resolution and incorporates ERA5-based spatial patterns. I was very happy to contribute to this paper, including graphs and comparisons with other datasets. essd.copernicus.org/preprints/es...
essd.copernicus.org
Berkeley Earth Surface Temperature – High-Resolution (BEST-HR): a 0.25° Global Gridded Temperature Data Set for Climate Monitoring
Abstract. We present version 2 of the Berkeley Earth Surface Temperature dataset, a global observational temperature record that now features enhanced spatial resolution (0.25° × 0.25°) and a new regr...
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Reposted by Bruce Calvert
Zeke Hausfather @zekehausfather.com · 01/09/2026
Our Berkeley Earth high resolution dataset paper is now available for open review over at ESSD! Thanks to @rarohde.bsky.social and Bruce Calvert for all the hard work to get it released: essd.copernicus.org/preprints/es...
essd.copernicus.org
Berkeley Earth Surface Temperature – High-Resolution (BEST-HR): a 0.25° Global Gridded Temperature Data Set for Climate Monitoring
Abstract. We present version 2 of the Berkeley Earth Surface Temperature dataset, a global observational temperature record that now features enhanced spatial resolution (0.25° × 0.25°) and a new regr...
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Reposted by Bruce Calvert
Zeke Hausfather @zekehausfather.com · 01/09/2026
The emissions scenarios underlying the next generation of climate model runs that will be featured in the upcoming IPCC 7th Assessment Report are officially out! I have a big new explainer over at Carbon Brief taking an in-depth look at what they mean and whats changed: www.carbonbrief.org/...
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Bruce Calvert @brucettcalvert.bsky.social · 01/09/2026
The Berkeley Earth version 2 paper is now in preprint. The new version is 0.25° resolution and incorporates ERA5-based spatial patterns. I was very happy to contribute to this paper, including graphs and comparisons with other datasets. essd.copernicus.org/preprints/es...
essd.copernicus.org
Berkeley Earth Surface Temperature – High-Resolution (BEST-HR): a 0.25° Global Gridded Temperature Data Set for Climate Monitoring
Abstract. We present version 2 of the Berkeley Earth Surface Temperature dataset, a global observational temperature record that now features enhanced spatial resolution (0.25° × 0.25°) and a new regr...
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Bruce Calvert @brucettcalvert.bsky.social · 13/08/2026
Example: www.nature.com/articles/s41... I thought David Anthoff was one of your former grad students.
nature.com
Comprehensive evidence implies a higher social cost of CO2 - Nature
Coupling advances in socioeconomic projections, climate models, damage functions and discounting methods yields an estimate of the social cost of carbon of US$185 per tonne of CO2—triple the wide...
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Bruce Calvert @brucettcalvert.bsky.social · 13/08/2026
Kopits et al included wildfire smoke in their latest assessment. arxiv.org/html/2509.00...
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Bruce Calvert @brucettcalvert.bsky.social · 13/08/2026
But many SCC costs include refrigeration and heating expenses.
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Bruce Calvert @brucettcalvert.bsky.social · 13/08/2026
Climate models also ignore cheese and jellyfish... so I'm not sure if this is a useful metric. On cheese, many climate-economy models use input-output tables that account for dairy products (e.g. by World Bank, OECD, IMF, MIT, Kyoto University).
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Bruce Calvert @brucettcalvert.bsky.social · 16/07/2026
Don't give them ideas. They might blot out the sun.
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Bruce Calvert @brucettcalvert.bsky.social · 15/07/2026
Yes, I was concerned about tornados in Ottawa yesterday, but luckily the wildfire smoke saved us.
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Bruce Calvert @brucettcalvert.bsky.social · 02/07/2026
Will the land changes be applied to GloSATLAT as well?
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Bruce Calvert @brucettcalvert.bsky.social · 21/05/2026
I read you 2024 paper last year. It was very informative. Thanks for sharing.
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Bruce Calvert @brucettcalvert.bsky.social · 13/05/2026
In any case, the Sherwood et al. study and Nic Lewis' publication use an approach that throws out useful time series information between the start and end of the industrial period, which could be used to better constrain climate sensitivity. It would be better to switch to time series methods.
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Bruce Calvert @brucettcalvert.bsky.social · 13/05/2026
Couldn't you just email him for the code if its not publicly available?
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Bruce Calvert @brucettcalvert.bsky.social · 07/05/2026
I was also fooled by the 20% claim.
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Bruce Calvert @brucettcalvert.bsky.social · 10/04/2026
Some integrated assessment models have the ability to calculate the social cost of individual greenhouse gasses and by year. Although this requires defining a utility function, so depends on choices of the time discount rate and how marginal utility declines as people get richer.
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Bruce Calvert @brucettcalvert.bsky.social · 10/04/2026
My Canadian brain has difficulty interpreting this information. In Canada, we have deputy ministers, who are civil servants and usually have technical expertise. Google tells me that junior ministers in the UK are political appointees rather than civil servants. Is that correct?
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Bruce Calvert @brucettcalvert.bsky.social · 03/04/2026
Admittedly, I don't think the IPCC scenarios considered "anti-woke energy" policies. Overall, I agree with your claim that there is a lot more irrationality and predictability in the world than often assumed. But I doubt if that can be extended to the full range of IPCC scenarios.
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Bruce Calvert @brucettcalvert.bsky.social · 03/04/2026
While it is true that many of IPCC's scenarios assume some level or rationality, the range of assumptions used in the IPCCs scenarios is quite broad. SSP3-7.0 assumes conventional wars, trade wars and no climate policies.
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Bruce Calvert @brucettcalvert.bsky.social · 02/04/2026
Given global tariffs, the fact that climate change impacts the economy, and the existence of plentiful oil and gas reserves (relative to SSP5 assumptions), do you think that SSP5-8.5 realistic?
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Bruce Calvert @brucettcalvert.bsky.social · 02/04/2026
Oil and gas reserves are assumed to be very limited in SSP5-8.5, so people stopping filling up their cars with gasoline and switch to liquefied coal. Despite this, everyone adopts the best scrubbers to limit aerosol emissions.
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Bruce Calvert @brucettcalvert.bsky.social · 02/04/2026
SSP5-8.5 and SSP3-7.0 are quite different. SSP5-8.5 involves free trade and global cooperation (except for climate change) to advance fossil fuelled human development. Everyone is super rich is SSP5 and climate change is assumed to have zero impact on the economy.
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Bruce Calvert @brucettcalvert.bsky.social · 13/03/2026
La lien dans vote profile indique que vous avez travailler avec la modèle IMACLIM et l'IIASA. Donc vous avez beaucoup d'éxperience dans cette domain.
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Bruce Calvert @brucettcalvert.bsky.social · 13/03/2026
Admittedly, this is the phase 5 documentation, whereas the graph uses phase 4 results.
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Bruce Calvert @brucettcalvert.bsky.social · 13/03/2026
See the technical documentation document available here: www.ngfs.net/en/publicati...
ngfs.net
NGFS Climate Scenarios for central banks and supervisors - Phase V | Network for Greening the Financial System
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Reposted by Bruce Calvert
Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
Regarding a recent community science paper on 1.5°C of #globalwarming (doi.org/10.5194/essd...), the graph I like the most shows #seaice extent anomalies for different datasets and reconstructions. The most striking feature is HadISST2 disagreement with Antarctic reconstructions.
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Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
I intended for the graph to be accessible to red-green colorblind people, but authors kept finding additional recent reconstructions. Here is my attempt at a red-green accessible version. Feedback would be welcome. The community paper is open for public comment until March 11.
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Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
However, many other datasets might underestimate #warming despite using HadISST2 since they often don’t account for climatological differences between #seaice and open sea. This issue is discussed in section 3 of the paper as well as in my 2024 paper (doi.org/10.1002/qj.4...).
doi.org
Improving global temperature datasets to better account for non‐uniform warming
This paper suggests two improvements to better account for spatially non-uniform warming in thermometer-based global temperature datasets: allowing underlying warming trends in the dataset to vary sp....
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Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
As a result, two datasets that I produce (HadCRU_MLE and DCENT_MLE), and perhaps Berkeley Earth, overestimate #warming since 1850. My 2024 paper (doi.org/10.1002/qj.4...) describes another mechanism (discontinuous temperature fields) that could contribute to overestimation.
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Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
The 1929-1939 climatology was designed to be conservative to warn sailors of potential #seaice danger rather than to be representative of average #seaice conditions. This is relevant since almost all global instrumental temperature datasets since 1850 rely on HadISST2. doi.org/10.14430/arc...
doi.org
Atlas Der Eisverhaltnisse Des Nordatlantischen Ozeans Und Ubersichts-Karten Der Eisverhaltnisse Des Nord- Und Sudpolar - Gebietes. Deutsches Hydrographisches Institut | ARCTIC
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Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
Prior to 1940, HadISST2 uses a German 1929-1939 reconstruction, which included observations from whaling ships, the British-Australian-NZ Expedition, and Nazi attempts to claim New Swabia for the 3rd Reich prior to WW2. This climatology was likely misinterpreted.
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Bruce Calvert @brucettcalvert.bsky.social · 28/02/2026
Regarding a recent community science paper on 1.5°C of #globalwarming (doi.org/10.5194/essd...), the graph I like the most shows #seaice extent anomalies for different datasets and reconstructions. The most striking feature is HadISST2 disagreement with Antarctic reconstructions.
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Bruce Calvert @brucettcalvert.bsky.social · 27/02/2026
Two other comments. 1. Mitigation costs in the graph are largely the result of a global uniform carbon tax. If society chooses a less optimal policy then mitigation costs can be much higher. 2. At least the graph doesn't exaggerate damages via a 8.5 W/m2 scenario.
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Bruce Calvert @brucettcalvert.bsky.social · 27/02/2026
The source is the Network for Greening the Financial System. Their results and methodological details are all available from their website. Unfortunately, the graph has many issues, such as using a damage function that has been retracted by nature.
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Bruce Calvert @brucettcalvert.bsky.social · 27/02/2026
There are more reliable estimates of climate damages that can still communicate that climate change can have substantial negative impacts. Please use alternative estimates. The graph you provide is unfortunately misinformation about climate change.
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Bruce Calvert @brucettcalvert.bsky.social · 27/02/2026
The Kotz et al. damage function conceptually includes extreme weather effects, so even if there were no Uzbekistan issue, this graph double counts damages. Finally, the NGFS acute damage estimates are biases since they account for extreme heat changes but not extreme cold changes.
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Bruce Calvert @brucettcalvert.bsky.social · 27/02/2026
NGFS phase 4 used the kotz et al damage function, which has been retracted from nature due to its results being based on faulty Uzbekistan data. www.nature.com/articles/s41... Futhermore, you graph adds NGFS acute and chronic damages.
nature.com
Data anomalies and the economic commitment of climate change - Nature
Nature - Data anomalies and the economic commitment of climate change
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Reposted by Bruce Calvert
John Kennedy @micefearboggis.bsky.social · 23/02/2026
How well can we quantify when 1.5 °C of global warming has been exceeded? Open review until 11 March essd.copernicus.org/preprints/es...
essd.copernicus.org
How well can we quantify when 1.5 °C of global warming has been exceeded?
Abstract. Parties to the 2015 Paris Agreement agreed to limit the long-term increase in global average temperature to well below 2 °C and pursue efforts to keep temperatures below 1.5 °C relative to p...
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Reposted by Bruce Calvert
Elizabeth Kent @lizk40.bsky.social · 13/02/2026
The paper describing the new DCENT-I dataset of monthly global surface temperature since 1850 is just published. rmets.onlinelibrary.wiley.com/doi/10.1002/...
rmets.onlinelibrary.wiley.com
DCENT‐I: A Globally Infilled Extension of the Dynamically Consistent ENsemble of Temperature Dataset
DCENT-I infills data gaps in DCENT, producing spatially coherent temperature fields (top) and a slightly higher GMST warming estimate (bottom). Top: December 1877 temperature anomalies (°C; 1961–1990...
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Bruce Calvert @brucettcalvert.bsky.social · 10/02/2026
Statistical forecasts can be okay, but people proposing such models need to check for overfitting using standard tests. If there is physical information available then it makes sense to try to account for that.
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Bruce Calvert @brucettcalvert.bsky.social · 28/01/2026
William Nordhaus (Nobel prize winner) proposes a carbon compact where a coalition of countries agree to a carbon tax rate and tariff non-compliant countries. This would be a more reliable way to deal with the free rider problem of emissions reductions.
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Bruce Calvert @brucettcalvert.bsky.social · 28/01/2026
Clean energy targets are less economically efficient compared to broad-based carbon taxes as the latter treats all emissions reductions equally so better allows for competition between emission reductions. You can also relate carbon tax rates to the social cost of carbon.
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Bruce Calvert @brucettcalvert.bsky.social · 19/12/2025
HILL-1 appears to be based on RCP8.5, including 95th percentile results. It is surprising that this is described as "plausible". I thought that RCP8.5 was no longer considered to be part of the range of plausibility, including by the working group developing CMIP7 scenarios.
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Bruce Calvert @brucettcalvert.bsky.social · 04/12/2025
Let's add some nuance here. The direction of impact that AI will have on #climate emissions is disputed: www.nature.com/articles/s44...
nature.com
Green and intelligent: the role of AI in the climate transition - npj Climate Action
npj Climate Action - Green and intelligent: the role of AI in the climate transition
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