Corinne Le Quéré on the global carbon cycle

Deciphering the global carbon cycle is as fascinating as it is difficult. There are carbon fluxes in and out of the planet, all over the place, and at all time scales. Observational gaps are numerous and gaping. Uncertainties on country level emissions are increasing. Yet the global carbon budget is perhaps THE central bit of knowledge that society must have, if an informed decision on carbon mitigation is ever to be made. Corinne Le Quéré from the University of East Anglia is working to quantify — with enormous effort — just such a budget. You might think it’s like balancing a checkbook, and you’d be right. But only if your checkbook includes investments with unknown and time-variable interest rates, and frequent, untraceable withdrawals. As Corrine tells Mike, in spite of the massive challenges, the carbon cycle community is making tremendous progress in pinning down the many elusive processes that ultimately control the main variable of interest: atmospheric CO2 levels.

Music: Hallon by Christian Bjoerklund CC BY-NC-SA 3.0.

Joe McConnell on the scientific riches in tiny bits of ice

Most everyone you’ve heard on Forecast has a twisty career path. But Joe McConnell took an unusually circuitous route to his current role as a leading ice core scientist. Joe bombed as a dishwasher, thrived as a post-hole digger, started a consulting company as a teenager, considered anthropology and environmental law for his studies, switched gears to signal processing for oil exploration, traveled the world, returned to grad school with the aim of starting a hydrological consulting company, but ultimately returned to work on one of his enduring passions — the high latitudes. Now, Joe and his crew melt and analyze tiny bits of ice cores in one of the world’s premier continuous flow analysis labs. The samples are small, but the output is huge: major leaps in our understanding of black carbon, volcanism, and the interactions between humanity and the Earth system.

Joe McConnell, on Svalbard.

Peter Cox’s emergent insights

In Episode 54 of Forecast, Peter Cox from the University of Exeter gives Mike the inside story about how the “emergent constraints” approach is reshaping our ability to wring every last drop of useful information from climate models. It’s a two step process. First, using climate models, establish a relationship between something you care about in the future to something that is mechanistically related and for which we have modern/historical observations. Then, construct a meta-model that is constrained by the models’ varying ability to simulate the observed variable. Bob’s your uncle. It can be more complicated than that, but Peter’s genius is identifying, probing, and polishing simple nuggets of science, many of which end up published in Nature. And speaking of Nature, we kick it off by discussing the benefits of knowing and, let’s just call it, “handling” your editors.

Peter Cox at work.

Into the woods with Julia Pongratz

In episode 53 of Forecast, Mike talks with Julia Pongratz from the Max Planck Institute for Meteorology about the role of land cover and land use change in the climate system. Julia began working on the topic with an unbelievable challenge: simulating the impacts of LCLUC over the past millennium. Now her interests encompass geoengineering, climate mitigation and model intercomparisons, with a focus on understanding the ever-complex interactions among biophysical and biogeochemical feedbacks. Also, Julia assures Mike that, unlike in Maine, the ticks aren’t too horrendous in Germany. Probably. At least in the big cities.


Antarctic sea ice with Marilyn Raphael

In episode 52 of Forecast, Mike and Marilyn Raphael from the University of California at Los Angeles talk about Antarctic sea ice. Arctic sea ice is, on a relative scale, well understood: observations and models show a massive decline. Antarctic sea ice is weirder. Overall, the extent of Antarctic sea ice is increasing, slightly. But this masks nearby areas with both large increases and decreases. Mike and Marilyn discuss the many mechanisms that might be underlying the interesting and somewhat bedeviling trends, as well as the multitude of ways in which Antarctic sea ice interacts with the broader climate system. We wrap up with a personal discussion of what it’s like being an introvert in science, and some ways to navigate the often-draining interpersonal demands.

Marilyn Raphael

The hot world of cold ice with Jérôme Chappellaz

In episode 51 of Forecast, Jérôme Chappellaz regales Mike with all manner ice core tales. The early days of discovering that methane varies hugely between glacial and interglacial states; profligate consumption of ice in the early days; the intensely competitive yet fundamentally friendly nature of the field; the ever-present need to take scientific risks; documentary film making. Spontaneity, chance and inspiration dominate the conversation. Jérôme’s insomnia while in Antarctica leads to the crazy dream of Subglacior, a radical development in ice core technology, and a meeting with royalty leads to funding for the Ice Memory project. Perhaps unique among the geosciences, the ice core community and Jérôme in particular are constantly faced with disappearing/melting records, and the pressing need to create an ice archive for the next generation and whatever hammers will be in their toolbox. Leading to … sequencing the history of the Black Plague from ice cores, maybe?

Credit: CNRS Phototheque

The bassline of climate with Julien Emile-Geay

In episode 50 of Forecast, Julien Emile-Geay from the University of Southern California calmly presents a somewhat radical world view. Love of jazz as a means of selecting a grad school; universities as revolutionary institutions; pursuit of science as a subversive activity. Even more unusual: considering data and models not as separate entities, but as co-equal, and integral, facets of research into paleoclimate dynamics. For example, Julien is leading efforts on both massive data compilations, and on the massive Last Millennium Reanalysis. Progress is coming on many fronts, including ENSO dynamics, the always-controversial topic of solar-climate interactions, and low frequency climate variability — what Julien calls the “bassline of the climate soundtrack”.

Credit: USC media office

The arc of TEX86 with Jessica Tierney

In this episode of Forecast, Jess tells Mike about the origins of the TEX86 temperature proxy — an index of membrane lipids produced by mesophilic archaea. The origins in the 1980s in extreme ocean environment; discovery of membrane production in a huge range of environments; brute force discovery of the index; the inevitable struggles to understand what it actually represents; an unusually active and sometimes dismissive debate about its usefulness. All proxies have issues, but Jess and her colleagues are converging on the what/when/where for TEX86’s application. For Jess, work on TEX86 (and other methods!) is leading to an improved understanding of the atmospheric dynamics, surface processes, and feedbacks governing past climate variability, particularly in the tropics.

Jess Tierney

Connecting Kevin Anchukaitis

Kevin Anchukaitis from the University of Arizona is probably best known for his work on dendroclimatology, but this is changing quickly. Now, his broader interests in the connections among history, political science, archaeology, statistics, climate modeling, and forward modeling of proxies are increasingly mirrored within the broader field of late Holocene paleoclimate research. Now, it’s possible to bring together this astonishingly wide range of evidence to disentangle, for example, the influence of volcanic eruptions on climate and society. It ends up sounding like a golden age for climate science, if not for the extinct Monteverde golden toad, whose extinction Kevin showed to be due to a fungal disease coupled with natural climate variability. As always, with good science, you have to go where the evidence takes you.

Trace metals and thrash metal with Kaustubh Thirumalai

People find science for all kinds of reasons. Some are born to it, but usually not. Most people find science by bumping into it at a bar, getting help from it while fixing a flat tire, seeing it alight on a leaf, iridescent, or watching it pass by on a subway car going the other way.

Kau aboard the JOIDES Resolution as part of Expedition 353, sailing in the Bay of Bengal in 2015. Photo by Sungham Kim from the Korea Polar research Institute.

For Kaustubh Thirumalai (Kau), the stage was set with burnout on chemical engineering in India coupled with a side job reviewing comics and black metal for a friend’s website. Then, almost randomly searching for an interesting internship, he hooked up with Prosenjit Ghosh, for whom he worked as a local fixer, helping to procure parts for the construction of a mass spec. After that, it was geosciences, full-on: a move to the US, interests in the techniques and concepts of paleoclimate, and an ever-expanding network of collaborators. But still comics and metal! Just now with a splash of trace metals — little bundles of strontium and company, waiting to be discovered.


Intro music is from the album Terminal Redux by Vektor, ranked by Kau as the #1 metal album of 2016. Extro music is Quartz, by Kau himself. All music used by permission — thanks Dave and Kau! Photos are by Kau, used by permission.