Geert Jan trained as a physicist and started working on climate in 1996, when he joined KNMI as a postdoc. In the 2000s, he created the “Climate Explorer”, a platform to analyse climate data. He did so single-handedly and with little funding; it remains one of the most useful tools for accessing and analysing climate data available to the world. His desire to share everything he made, and for science, data and tools to be open, advanced climate science and meant that results were more easily accessible for the general public.
Geert Jan realised we needed to answer not just the simple questions, or those with the most immediate scientific rewards, but the ones that mattered. He was deeply motivated to make his science valuable to society and especially to the most vulnerable, as reflected in some of the earliest analyses of changing extremes in Africa and his pioneering work on rapid attribution of extreme events
As the joint founder and leader of WWA, Geert Jan was central to its work to investigate and explain how climate change is influencing weather today. His work received growing scientific, political and social attention: this year alone he was recognised with a royal honour in the Netherlands, the European Meteorological Society’s Technology Achievement Award and Time Magazine’s listing of the world’s most influential people. Attribution science was identified as one of the “breakthrough technologies” of 2020 by the MIT Technology Review, and was one of the major advances reported in the IPCC’s Sixth Assessment Report.
Beyond his scientific achievements, Geert Jan was a passionate, generous and inspirational colleague, friend and role model to his collaborators at WWA and to many others. His honesty, kindness and morality shone through his life and work, leaving fellow scientists, students and friends mourning his loss but grateful for having known and worked with him. His legacy will be immense.
Reflections from some of us, Geert Jan’s WWA colleagues:
“He was one of the really great ones, but he didn’t have a big ego, he never quite believed just how good he was. He was not recognised enough. Geert Jan taught me so much, but the most important thing was to have fun in your work. And he was so much fun to work with.”
“Such a deep understanding of data – from observations and models – he would immediately have a story for each dataset, switching from broad insights about the global climate to specific events, and from quality of large reanalysis data sets to data gaps or instrument changes in a particular weather station.”
“Something that I’ve personally witnessed many times, from my first interaction with him as a master student at an EGU poster, to recent intense back-and-forth about the Australian bushfire paper: his moral compass was always pointing in the right direction and his ego was so down-to-Earth that you couldn’t tell the difference between his interacting with famous professors or new students in terms of the respect and attention he’d give the discussion. We thus not only lose an exceptional scientist, but also a role model for scientific and ethical integrity.”
“Everyone who had the privilege to learn from you came out the other end as a better scientist or student. You weren’t afraid to call a spade a spade, contributing massively to advancing the sciences in the best possible way, at a scale only few ever achieve. On a human level, you’ve been a beacon of hope even when the stupid cancer consumed much of your energy. Which didn’t keep you from being wildly productive. Your positivity kept you going. The same positivity that was so contagious to colleagues and students who were lucky enough to work with you.
“But what I personally most admired – apart from your general kindness – was how you dealt with your cancer treatment journey. You’ve been open about it from the start and pushed people to get over the awkwardness associated with disease and death in our society. You’ve been no less than a role model for a societal transition in that regard. I for one will follow your lead for the remainder of my life, and despite the numbness and devastation that we alI feel right now, your unique legacy is going to live on forever. Lastly, there’s never the right time to go, but there is a sense of relief that you, Geert Jan, were put on the list of the most influential 100 people in 2021 while you were still with us. You have deserved no less than that! You will be sorely missed!”