Valérie Masson-Delmotte and the jigsaw puzzle of climate science

For Valérie Masson-Delmotte, climate science is like a jigsaw puzzle. Unlike a house of cards, where the removal of one element causes the whole thing to crash down, the central picture of a puzzle is still apparent when pieces — maybe even many pieces — are missing.

MASSON-DELMOTTE Valérie
Valérie Masson-Delmotte. Rights-free image by Pierre Maraval for the “1000 Researchers project”.

Valérie works, at least in part, to fill in the missing pieces, using tools like ice cores, climate models, and statistics. I guess you could say that Valérie is an ice core scientist, but that’s like saying that Eric Ripert knows how to cook fish. Yes he does, and he’s great at it, but that kind of misses the bigger picture.

In fact I would have a hard time trying to pin down what Valérie does, because the range is so broad, spanning monsoon modeling, polar climate variability, interpretation of δ18O, age models, volcanic impacts on climate … I suppose it’s simplest to say that Valérie is trying to understand past climate variability and the underlying processes, on an astonishing variety of fronts. A great example of how Valérie and her colleagues are bringing together multiple archives and techniques is a recent Nature paper on the reconstruction of the North Atlantic Oscillation.

Figure 2 from "A model-tested North Atlantic Oscillation reconstruction for the past millennium" by Ortega et al. doi:10.1038/nature14518.
Figure 2 from “A model-tested North Atlantic Oscillation reconstruction for the past millennium” by Ortega et al. doi:10.1038/nature14518.

That’s not all, though. Valérie is the co-chair of Working Group I for the sixth IPCC assessment report, a children’s book author, and the mother of two teenage daughters.

It seems like nearly everyone gets into science by some roundabout way. In Valerie’s case, her early interest in archaeology morphed into engineering. But then, in the process of deciding whether or not to stay in science, a chance encounter with a popular science article on the Vostok ice core led to her cold-calling the French scientists who were involved in the project, and soon, the day after finishing her PhD on monsoon modeling, a postdoc at the new LSCE with the great Jean Jouzel.

The timing was perfect and, for a brief time, Valérie and her colleagues could pursue any sort of curiosity-driven science they wanted. Those days are long gone, but Valérie is still a passionate supporter of long-term, curiosity-driven science.

One theme that keeps emerging in my interviews with climate scientists is the way in which larger cultural practices inform how science gets done. For Valérie, French culture has some specific practices, particularly around raising questions. As she says, “We are not taught to ask questions … questions are supposed to reflect how smart you are … but not acknowledge your ignorance”. Yet it doesn’t seem that Valérie has any issues asking tough, reasonable questions, like when she takes me to task for not accepting important methodological advances for publication in Nature (at least in climate).

Our interview, recorded at the end of the March 2016 IPICS meeting in Hobart, Tasmania, was a great chance to hit some of the nitty-gritty of ice core science. We hash through CO2 offsets, age model synchronization with speleothems and tephra, integration of ice core records with ocean and non-polar terrestrial records, and the hunt for the oldest ice.

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