Tim Osborn

@timosbornclim.bsky.social

2545 Followers 505 Following

Climate variability and change | Professor of Climate Science & Director of Climatic Research Unit | UEA | Views expressed here are my own, not UEA's

Global temperature time series 1850-2026 from HadCRUT5 dataset

View of Start Bay from Start Point

View of the Thames including London Eye

Figure 1 from Santer et al. (2026) showing agreement between model predictions and observations of global temperature change across multiple stratospheric and tropospheric layers.

This Climate Data Dashboard provides timeseries for individual countries and other territories, calculated using version
4.09 of the CRU-TS and CRU-CY datasets.

We remain neutral with regard to any jurisdictional claims.

These datasets have been created by the Climatic Research Unit (CRU) and the National Centre for Atmospheric
Science (NCAS), both at the University of East Anglia (UEA).

You are encouraged to freely use and share these graphs and data if you acknowledge NCAS and CRU-UEA as the creator. If it is appropriate to include a scientific reference, then please also cite "Harris et al. (2020) Scientific Data".

Chile CRU-TS / CRU-CY annual drought area (%)

France CRU-TS / CRU-CY annual drought area (%)

A screenshot of the CRU-TS national time series dashboard

Highlighted quote: “What determines whether someone embraces science? The survey examines the influence of science capital, the sum of one’s interactions with science through work, study, family, friends and leisure, and a guiding principle for the Science Museum Group.

Among those with high science capital, 84% support government funding for blue-skies research and 84% agree science has increased their personal prosperity. Among those with low science capital, just 44% and 13% respectively agree.”

HadCRUT5 global temperature from 1850 to 2025, with 2025 value highlighted. Uncertainty range is included but with offset from 1981-2010 to make it clear where the greatest uncertainty lies.

2025 values highlighted in a separate panel for each individual dataset, relative to their own individual 1850-1900 baselines (or their own convention for this baseline if they do not cover this period with their own data).

Multi-dataset comparison of global temperatures from 1850-2025. Baseline is a combination of 1850-1900 means.

Multi-dataset comparison of global temperatures from 1850-2025, with 2025 values highlighted in a separate panel for each individual dataset. Baseline is a combination of 1850-1900 means.

PhD Positions

I have three funded projects currently available.

Closing date 10 December 2025:

Redeveloping Central England Temperature: Modernising a Historic Climate Series (CASE project with Met Office) (main supervisor: Tim Osborn; co-supervisors: Stephen Packman, Met Office, Ed Hawkins, University of Reading, Andrew Friedman, UEA)

Closing date 7 January 2026:

Causes and Syndromes of Extreme Wildfires in Tropical and Extratropical Forests (main supervisor: Matt Jones; co-supervisor: Tim Osborn)

Closing date 7 January 2026:

Predicting and Mitigating Megafires under Climate Change (CASE project with WTW) (main supervisor: Matt Jones; co-supervisor: Tim Osborn)

Estimates temperature changes from 1400-1960 over the mid to high latitudes of the Northern Hemisphere as a function of longitude covering North America, Europe and Russia. From work by Tim Osborn and colleagues in 2004, based on records of tree-ring maximum latewood density.

1850-2025 time series of global mean temperature anomaly from the HadCRUT5 dataset.

Screenshot from diagrammonkey blog which says:

"A recent paper on sea level change concludes that “approximately 95% of the suitable locations show no statistically significant acceleration of the rate of sea level rise. The investigation suggests that local, non-climatic phenomena are a plausible cause of the accelerated sea level rise observed at the remaining 5% of the suitable locations.”

Having read the abstract, one can guess – more or less – what the problem is as it’s straight out of the sceptic playbook.

1. Take a global indicator with a clear signal

2. Break it down into as many local estimates as possible, maximising the noise to signal ratio.

3. Test each local change independently using a statistical significance test that is predisposed to accept the null (no change/no accelerations or whatever) and does not account for the possibility of a common signal.

4. Aggregate the results of the individual tests back up to the global scale (again ignoring any possible common signal) and express disbelief that anyone thought there was something there.

It’s a way to avoid seeing the forest by a very careful study of all the individual trees."

Transcript:

5. TROPOSPHERIC TEMPERATURE
—S. Po-Chedley, J. R. Christy, C.-Z. Zou, C. Mears, and L. Haimberger
Record-high global lower tropospheric temperature (LTT) values in the second half of 2023 persisted through boreal summer in 2024 (Fig. 2.9), producing a 2024 global-mean LTT that was 0.84°C (0.77°C–0.92°C depending on dataset) above the 1991–2020 climatological mean (Fig. 2.10). All nine tropospheric temperature datasets considered here (Table 2.3) ranked 2024 as the warmest year for global LTT, making 2023 the second-warmest year in most datasets.

Excerpt from IPCC Sixth Assessment Report, Working Group 2, Chapter 3 Executive summary. Text reads as follows:

Climate impacts on ocean and coastal ecosystems will be
exacerbated by increases in intensity, reoccurrence and
duration of marine heatwaves (high confidence), in some cases,
leading to species extirpation, habitat collapse or surpassing
ecological tipping points (very high confidence). Some habitat forming coastal ecosystems including many coral reefs, kelp forests and
seagrass meadows, will undergo irreversible phase shifts due to marine heatwaves with global warming levels >1.5°C and are at high risk this
century even in <1.5°C scenarios that include periods of temperature
overshoot beyond 1.5°C (high confidence). Under SSP1-2.6, coral
reefs are at risk of widespread decline, loss of structural integrity and
transitioning to net erosion by mid-century due to increasing intensity
and frequency of marine heatwaves (very high confidence). Due to
these impacts, the rate of sea level rise is very likely to exceed that
of reef growth by 2050, absent adaptation. Other coastal ecosystems,
including kelp forests, mangroves and seagrasses, are vulnerable to
phase shifts towards alternate states as marine heatwaves intensify
(high confidence). Loss of kelp forests are expected to be greatest
at the low-latitude warm edge of species’ ranges (high confidence).
{3.4.2.1, 3.4.2.3, 3.4.2.5, 3.4.4}

1986 to 2025 time series of hard coral cover for the Southern Great Barrier Reef

1986 to 2025 time series of hard coral cover for the Central Great Barrier Reef

1986 to 2025 time series of hard coral cover for the Northern Great Barrier Reef

Timeseries of winter-average NAO index

Photo of Ben Santer

Outcome: On Saturday, WGI agreed to the revised chapter outlines for its contribution to AR7, as set out in IPCC-LXII/Doc. 11. The report will include the following chapters:

Chapter 1: Framing, methods and knowledge sources;
Chapter 2: Large-scale changes in the climate system and their causes;
Chapter 3: Changes in regional climate and extremes, and their causes;
Chapter 4: Advances in process understanding of Earth system changes;
Chapter 5: Scenarios and projected future global temperatures;
Chapter 6: Global projections of Earth system responses across time scales;
Chapter 7: Projections of regional climate and extremes;
Chapter 8: Abrupt changes, low-likelihood high impact events and critical thresholds, including tipping points, in the Earth system;
Chapter 9: Earth system responses under pathways towards temperature stabilization, including overshoot pathways; and
Chapter 10: Climate information and services.

Cover page of the candidate brochure for a Senior Research Associate / Climate Data Scientist post at UEA

A map showing the pattern of long-term warming estimated from the HadCRUT5 global temperature dataset

Graph showing timeseries of global temperature change from the pre-industrial level to 2024 from 6 different datasets, plus a panel comparing their 2024 values. Four are slightly above 1.5C, two are slightly below 1.5C.

Fig 1a from Osborn and Kennedy 2024

Looking up at a Scots Pine silhouetted against a blue sky, with a jet plane contrail

Fallen tree with new shoots

Monckton wrote: "The real-time temperature updates will be very widely referred to. And the record will show that the extremists’ predictions are simply not coming to pass."