Toby Ord

@tobyord.bsky.social

Senior Researcher at Oxford University. Author — The Precipice: Existential Risk and the Future of Humanity. tobyord.com

B R O A D T I M E L I N E S We should have neither short AI timelines, nor long timelines, but a broad probability distribution over when transformative AI will arrive. My new essay explains why & explores the implications of such deep uncertainty. 🧵 1/

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The median age in China has rapidly caught up with the United Kingdom— In 1965, the median age in the United Kingdom was almost twice that of China. Half of the people in the UK were younger than 34 years, and half were older. In China, this midpoint was just 18 years.

The median age in China has rapidly caught up with the United Kingdom.

Line chart of median age for China and the United Kingdom from 1950 to 2025, with the vertical axis in years from 0 to 40 and the horizontal axis showing years 1950 to 2025. A line labeled United Kingdom stays around mid-30s in 1950, dips slightly to about 33 by the mid-1970s, then gradually rises to about 40 by 2025. A line labeled China starts around 22 in 1950, falls to about 18 to 19 in the mid-1960s and 1970s, then climbs steadily to meet the UK at about 40 in 2025. Annotated note: in the mid-1960s China’s median age was just under half that of the UK; another note states that today the median age in both countries is 40 years. Data source: UN, World Population Prospects (2024). License: CC BY.

Dim Red Dot Scientists have just released a photo featuring a dim red dot. It is the light of a single star exploding in a galaxy so far far away that that nothing we do could ever affect it — even in the very fullness of time. It lies beyond the Affectable Universe. Let me explain… 1/🧵

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It has become received wisdom in Brussels and Washington that there is a new “euro-sclerosis”: that the EU economy is lagging the US This view is wrong A little primer on the measurement of productivity – and why reports of the economic death of Europe are greatly exaggerated🧵

In an op-ed published today in TIME, Charlotte Stix and I discuss the serious risks associated with internal deployment by frontier AI companies. We argue that maintaining transparency and effective public oversight are essential to safely manage the trajectory of AI. time.com/7327327/ai-w...

When it Comes to AI, What We Don't Know Can Hurt Us

Yoshua Bengio and Charlotte Stix explain how companies' internal, often private, AI development is a threat to society.

time.com

The other evening I attended the launch of David Edmonds' book on Peter Singer's Shallow Pond. I was quite struck when he called it 'the most influential thought experiment in the history of moral philosophy' yet with no influence for its first 30 years… 🧵 press.princeton.edu/books/hardco...

Death in a Shallow Pond

From the bestselling coauthor of Wittgenstein’s Poker, a fascinating account of Peter Singer’s controversial “drowning child” thought experiment—and how it changed the way people think about charitabl...

press.princeton.edu

✍️ New article: “Foreign aid from the United States saved millions of lives each year” For decades, these aid programs received bipartisan support and made a difference. Cutting them will cost lives.

A bar chart illustrates the estimated lives saved each year by various American foreign aid programs, totaling approximately 3.3 million lives saved annually. The programs listed from top to bottom include:

- HIV/AIDS: 1.6 million lives saved per year
- Humanitarian aid: 550,000 lives saved per year
- Vaccines: 500,000 lives saved per year
- Tuberculosis: 310,000 lives saved per year
- Malaria: 290,000 lives saved per year

At the bottom, a note indicates that the figures represent central estimates and that actual estimates may range from 2.3 to 5.6 million lives saved. It clarifies that these numbers do not encompass other vital forms of aid such as water and sanitation, nutrition, and family planning. The source of the data is credited to Kenny & Sandefur, 2025. The visual includes a label stating "Our World in Data" and is presented under a creative commons attribution license (CC BY).

Evaluating the Infinite 🧵 My latest paper tries to solve a longstanding problem afflicting fields such as decision theory, economics, and ethics — the problem of infinities. Let me explain a bit about what causes the problem and how my solution avoids it. 1/N arxiv.org/abs/2509.19389

Evaluating the Infinite

I present a novel mathematical technique for dealing with the infinities arising from divergent sums and integrals. It assigns them fine-grained infinite values from the set of hyperreal numbers in a ...

arxiv.org

The Extreme Inefficiency of RL for Frontier Models 🧵 The switch from training frontier models by next-token-prediction to reinforcement learning (RL) requires 1,000s to 1,000,000s of times as much compute per bit of information the model gets to learn from… 1/11 www.tobyord.com/writing/inef...

The Extreme Inefficiency of RL for Frontier Models — Toby Ord

The new scaling paradigm for AI reduces the amount of information a model could learn per hour of training by a factor of 1,000 to 1,000,000. I explore what this means and its implications for scaling...

tobyord.com

Let’s take a look into GPT-5’s record-setting performance on FrontierMath. How did it perform on the holdout vs. non-holdout set, how did it do across tiers, and what new Tier 4 problems did it solve? 🧵

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Should we expect widespread moral progress in the future? In a new paper, Convergence and Compromise, @FinMoorhouse and I discuss this. Thread.

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The Code of Practice is out. I co-wrote the Safety & Security Chapter, which is an implementation tool to help frontier AI companies comply with the EU AI Act in a lean but effective way. I am proud of the result! 1/3

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Our new paper updating key metrics in the IPCC is now out, and the news is grim: ⬆️ Human induced warming now at 1.36C ⬆️ Rate of warming now 0.27C / decade ⬆️ Sharp increase in Earth's energy imbalance ⬇️ Remaining 1.5C carbon budget only 130 GtCO2 essd.copernicus.org/...

Indicators of Global Climate Change 2024: annual update of key indicators of the state of the climate system and human influence

Abstract. In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. Here we compile monitoring datasets (published at https://doi.org/10.5281/zenodo.15639576; Smith et al., 2025a) to produce updated estimates for key indicators of the state of the climate system: net emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radiative forcing, the Earth's energy imbalance, surface temperature changes, warming attributed to human activities, the remaining carbon budget, and estimates of global temperature extremes. This year, we additionally include indicators for sea-level rise and land precipitation change. We follow methods as closely as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One report. The indicators show that human activities are increasing the Earth's energy imbalance and driving faster sea-level rise compared to the AR6 assessment. For the 2015–2024 decade average, observed warming relative to 1850–1900 was 1.24 [1.11 to 1.35] °C, of which 1.22 [1.0 to 1.5] °C was human-induced. The 2024-observed best estimate of global surface temperature (1.52 °C) is well above the best estimate of human-caused warming (1.36 °C). However, the 2024 observed warming can still be regarded as a typical year, considering the human-induced warming level and the state of internal variability associated with the phase of El Niño and Atlantic variability. Human-induced warming has been increasing at a rate that is unprecedented in the instrumental record, reaching 0.27 [0.2–0.4] °C per decade over 2015–2024. This high rate of warming is caused by a combination of greenhouse gas emissions being at an all-time high of 53.6±5.2 Gt CO2e yr−1 over the last decade (2014–2023), as well as reductions in the strength of aerosol cooling. Despite this, there is evidence that the rate of increase in CO2 emissions over the last decade has slowed compared to the 2000s, and depending on societal choices, a continued series of these annual updates over the critical 2020s decade could track decreases or increases in the rate of the climatic changes presented here.

essd.copernicus.org