Professor Geert Jan van Oldenborgh

Obituary: Professor van Oldenborgh

Climate physics
Atmospheric, Oceanic and Planetary Physics

It is with great sadness that the Department of Physics shares the passing of Professor Geert Jan van Oldenborgh, Visiting Professor at the Department of Physics and a highly regarded and warmly respected colleague. Professor Myles Allen pays a personal tribute to his colleague and friend.

‘Geert Jan was an extraordinarily productive, imaginative and dedicated scientist, and it was an honour to have known, worked and (often) argued with him. Having begun his career amassing a pretty impressive CV in theoretical particle physics, he moved into meteorology and climate in the 1990s, joining Koninklijk Nederlands Meteorologisch Instituut (KNMI) where he has worked ever since. He was always interested in working on problems with potentially high impact for disadvantaged people, so he gravitated to seasonal predictability, working on dynamical systems models of El Niño and statistical forecast evaluation, both topics of prime interest for our own Atmospheric, Oceanic and Planetary Physics sub-department here at Oxford. He built the Climate Explorer, largely single-handedly and very much as a labour of love, which has provided thousands of graduate students and post-docs with their first access point for a wealth of datasets and model simulations, and largely as a result was drafted in to help with the Intergovernmental Panel on Climate Change’s (IPCC) Coupled Model Intercomparison Project (CMIP) atlas.
‘I had come across Geert Jan now and then during the early 2000s, always asking hard-to-answer questions in seminars, but got to know him well through his work as an IPCC author, where he was very much in the sceptical camp – in the right scientific sense of the word. Towards the end of the 2000s he started to publish on human influence on climate, and really pioneered the use of simple, transparent statistical models to identify signals of external drivers in the observed records, particularly of extreme events – he was a really valuable voice coming in from outside to the “attribution community”, which had become rather introverted at the time. Over the past decade he became more and more interested in the problem of extreme event attribution, building the World Weather Attribution project with Fredi Otto and Robert Vautard, but never stopped producing his monthly climate diagnostic presentation – even when he was getting really ill – combining fascinating insights into what was going on with weather around the world with plenty of humorous comments about media histrionics and the successes and failures of seasonal forecasts.
‘This past year saw a whole series of awards, including a Technology Achievement Award from the European Meteorological Society, a Knighthood from the Dutch Government for services to climatology, and being named as one of the 100 most influential people of 2021 by Time Magazine for his work on extreme weather, but I know he was particularly proud of his Visiting Professorship at the University of Oxford – and we were equally proud to be able to call him a colleague.
‘I will miss him. We all will.’

Geert Jan suffered with a rare bone cancer for many years, approaching successive treatments with an extraordinary combination of scientific objectivity and courage; we pass on our sincere condolences to his family and friends.

Read Professor Hans von Storch's interview with Professor van Oldenborgh from December 2020.