Geert Jan van Oldenborgh Obituary | Climate science

Geert Jan van Oldenborgh, who died at the age of 59 from multiple myeloma, was co-founder and member of a team of scientists that identified – at high speed and politically a hot topic – the links between the man-made climate change and forest fires, heat waves, drought, flooding and other specific weather disasters.

It’s more complicated than it looks. Extreme events have always happened, and for decades most climatologists were unwilling to say that any particular flood or heat wave was directly fueled by ever-increasing greenhouse gas emissions resulting from ‘rampant use of fossil fuels. If they did, it was usually long after the event.

That started to change six years ago, when Oldenborgh co-founded World Weather Attribution, an initiative designed to scrupulously examine the signal of climate change within individual and seemingly random extreme weather events.

In August 2021, he and his colleagues established that the deadly floods of July 2021 – in which more than 200 people died – in Belgium and Germany were made significantly more likely by global warming. In July, researchers found that the unprecedented temperatures that scorched the US Pacific Northwest and Canada in June would have been “virtually impossible” without climate change. After an unusually hot March, sudden April frosts devastated vineyards and orchards in central France; in June, Oldenborgh and his colleagues again identified the footprint of climate change.

And this year alone, using the traditional – and much slower – medium of the peer-reviewed scientific article, Oldenborgh and his partners also established the role of human-triggered climate change in the wildfires that ravaged Sweden in 2018; the danger of Australian bushfires; the pattern of drought and higher temperatures in East Africa; and the heat waves that hit Europe in June and July 2019. A fifth study declared the prolonged heat in Siberia in 2020 “nearly impossible” without human influence. All of this in the last 10 months of his life.

He was also the creator and custodian of an extraordinary digital platform called Climate Explorer, housing a vast data set – including systematic measurements of global temperatures; overall ozone loss; sunspot counting; forces of sea currents; sea ​​ice cover; temperatures in the UK since 1772; Precipitation in the Netherlands since 1906; ocean temperatures down to depths of 100 meters, 700 meters and 2,000 meters; tropical cyclones and Atlantic hurricanes; Reconstructed Asian monsoon droughts from 1300 to 2005; and even the beech harvest in the Netherlands from 1930 to 1967, all exploited today by thousands of researchers around the world.

In April, his work with Climate Explorer won him the Technological Excellence Award from the European Meteorological Society. The same month, he was made a Knight of the Order of the Lion of the Netherlands for his research. In September, his work with World Weather Attribution earned Oldenborgh and his research partner Friederike Otto of Imperial College London a place on Time magazine’s annual list of the world’s most influential people.

He was born in Rotterdam to Jan van Oldenborgh, lawyer, and Wil Lijbrink, psychoanalyst. While still in school in the Netherlands, he obtained a scholarship to Lester B Pearson College, near Victoria, British Columbia, where he studied Chinese. He graduated from Leiden University in the Netherlands in 1986 with a master’s degree in theoretical physics, which he continued with mathematics and Chinese, then in 1990 completed his doctorate at the University of Amsterdam and the NIKHEF, the Netherlands Institute for Nuclear and High Energy Physics.

He taught and continued his research on elementary particles at the Ludwig Maximilian University in Munich and the Paul Scherrer Institute in Switzerland, and returned to Leiden in 1994.

In 1996, he joined the Royal Netherlands Meteorological Institute, known as KNMI, to begin work on ways to improve predictions of this recurring natural climate phenomenon in the Pacific known as El Niño, which regularly disrupts global weather conditions. “Climate research turned out to be much more suited to my personality and offered more possibilities,” he told an interviewer last year, “and so it was easier to make meaningful contributions. . It was also much easier to explain to the public and the answers more relevant to society.

He has put his name on over 150 peer-reviewed research articles. His research career has taken him into the complex worlds of seasonal forecasting, climate modeling and, eventually, event attribution. He contributed directly to one of the Global Reports of the Intergovernmental Panel on Climate Change in 2013 and was appointed in 2019 as Visiting Professor at the University of Oxford.

He would later recall two “really cool” times in science when he felt he had discovered something new. The first took place during his career as a particle physicist. The second occurred while brainstorming with a colleague at KNMI to understand why Antarctica might melt as the extent of the sea ice around it increased. They believed that warming ocean currents would eat away at the base of the pack ice, while counterintuitively, melting land ice allowed the shelf area to increase during the southern winter. “In my perhaps simplistic philosophy of science, truth is how the world actually works. The scientific method prescribes a way to get closer to this truth, ”he said. “Although he can never fully describe it, he can come close to it.”

In 1982, he met his wife, Mandy, psychotherapist and clinical psychologist; they married in 1987 and had three sons. In 2013, she was diagnosed with Kahler’s disease, an incurable form of blood cancer also known as multiple myeloma. “I walked around with it for at least a year and a half before that,” he said.

But he continued to work for years of treatment. On September 20, he apologized for a difficulty on the Climate Explorer site. “Unfortunately, my health only allowed me to fix it this evening,” he wrote. “Please report the remaining issues. It was his last entry.

He is survived by Mandy and their sons, Elwin, Leon and Ingo.

Geert Jan van Oldenborgh, physicist and climatologist, born October 22, 1961; passed away on October 12, 2021

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