Dorthe Dahl-Jensen (Copenhagen, Denmark, 1958) received her PhD in Geophysics from the University of Copenhagen in 1988. She then took up a teaching and research position at this institution, with which she has remained associated throughout her career. Currently Villum Investigator Professor at the university’s Niels Bohr Institute, since 2018 she has also held a Canada Excellence Research Chair at the University of Manitoba (Canada). She led the Centre of Excellence for Ice and Climate at Copenhagen between 2007 and 2017, and has served as principal investigator on international programs ranging from deep drilling projects such as EastGRIP (East Greenland Ice-core Project) or NEEM (North Greenland Eemian Ice Drilling Project) to initiatives like Past4Future, funded by the European Union and involving 22 countries. She is also a researcher on the Green2Ice project, which in 2022 was awarded an ERC Synergy Grant worth 13.9 million euros.
Dorthe Dahl-Jensen’s work has primarily focused on the reconstruction of past climate from the study of ice cores in Greenland, as reflected in her 1998 paper in the journal Science. Her research has shown that past warming episodes tended to occur during periods of increased solar energy influx, which in turn drove up CO2 and thereby temperature levels, triggering a positive feedback loop. She also found, however, that greenhouse gas concentrations at no point matched their present levels. Even in warm periods like that of 115,000 years ago, they never exceeded 3,000 parts per million (ppm) of CO2, compared to a current average of 420 ppm. Hence the scientist’s concern about the possible impacts of today’s human-induced global warming, some of which, she believes, are probably unstoppable. Further, based on her research on abrupt changes in past climate, she warns of the risk of melting ice sending torrents of fresh water into the ocean. This, in turn, would disrupt the ocean currents that give Europe its mild winters, which, paradoxically, would cool the temperature in northern European countries, Denmark and also Spain.