A new seminar series was launched in 2024 as an opportunity for WHOI scientists to invite external speakers of international repute for a seminar and discussions on climate and the oceans. The goals are to:
- Promote interdisciplinary science on the ocean’s role in climate
- Provide the opportunity for students, postdocs and WHOI scientists to interact with an external scientist
- Create community and inter-departmental collaboration within WHOI
Past Events
Tuesday, April 23, 2024 • 3 pM
Perspectives on the warming Earth: A near miss and the ultimate cost
David Archer, University of Chicago
Abstract: I will present two bookended ruminations on anthropogenic climate change, one looking backward into the past, the other about the future. The first segment considers the question of what would have happened if the natural CO2 concentration in the atmosphere had been different than it turned out to be. If it had been lower, the radiative forcing from fossil fuel CO2 would have started impacting the weather sooner, which would have left less time for the technological development needed for decarbonization. We got lucky! The second segment is on how we assess future damages from climate change. The present-day value of future climate damages is called the social cost of carbon, and is based on the idea of discounting, to account for perpetual exponential growth and human selfishness. What if the discount rate were zero? We come up with a scale estimate of costs in present-day terms by integrating a fractional change in Earth’s human carrying capacity through time, multiplied by the present-day rate of global economic activity. In order to get this published, we had to figure out in what mythical world this calculation would be actually correct, which turns out to be an extrusion of today into the indefinite future, with no growth or technological development, and everyone living forever, like Groundhog day. Because carbon release alters climate for hundreds of thousands of years, the “ultimate” cost of carbon exceeds the “social” cost of carbon by many orders of magnitude.
View video
Passcode: 7s.hHe+@
Tuesday, November 19, 2024 • 3 pm
Antarctica and the global climate system: Observations, models, and chaos
Nick Golledge, Antarctic Research Centre, Victoria University of Wellington
Abstract: The Antarctic Ice Sheet holds enough freshwater to raise global sea level by 58 m. Understanding the timescales and magnitudes of its response to environmental drivers is therefore societally useful. Equally important, however, is an appreciation of its dynamical coupling with other Earth system elements, and the mechanisms by which these elements interact. This presentation will span all of these aspects, starting with field observations and data-constrained models. We will explore how validating our models with empirical data allows for reliable future projections, and how artificial neural networks now allow us to improve the robustness of those scenarios. From there we expand our horizon with simplified geometry experiments that can tell us about large-scale regime shifts over millions of years, revealing the way that ice sheets 'resonate' with environmental forcing. Finally, we'll look at how dynamical systems approaches can tell us something about Earth system behavior in a more conceptual sense, where growth and increasing connectivity allow for self-organization, and where positive feedbacks can sometimes drive a system towards chaos.
View video
Passcode: *PFws8u#
Thursday, May 1, 2025 • 12 PM • Redfield Auditorium
Climate change responses across realms and biological scales
Malin Pinsky, Ecology & Evolutionary Biology, University of California Santa Cruz
Climate change is driving a seemingly idiosyncratic reorganization of ecological communities around the world, but what general rules allow us to understand this change through time? I will present evidence suggesting the scales and processes of biological response differ fundamentally across realms, with a major role for individual adaptation in place on land and more widespread population-scale geographic shifts at sea. Despite these differences, rapid turnover in species compositions are occurring across realms. Taking a process-oriented approach to understanding global ecological change both reveals general rules and illuminates solutions to contemporary conservation challenges.
Zoom
Passcode: CBB1t!
Tuesday, May 13, 2025 • 12 pM • Clark 507
On microbes and particles: The ocean at the microscale
Roman Stocker, ETH Zurich
The sinking of organic particles is a main driver of carbon export from the ocean surface to depth, where it can remain stored for centuries. Only a small fraction of the particulate carbon that leaves the surface makes it to the ocean bottom, in part due to degradation of particles by marine bacteria. Yet, the processes by which bacteria find, colonise and degrade particles, and their associated rates, have remained largely unknown. I will present microfluidic experiments at the single-particle level to illustrate the rich interplay between particle dynamics and microbial processes, as well as mathematical models to scale up the observed particle degradation dynamics to predict the vertical carbon flux. I will focus on two findings. First, I will show that the rate of degradation of particles depends on the particle sinking speed, a process we termed ’sinking-enhanced degradation’, which couples two parameters (sinking rate, degradation rate) traditionally considered independent in carbon flux models. Second, I will present evidence that the sinking speed of particles is itself affected by microbial processes, not only through degradation, but also through the scavenging of bogeys of microbial origin, which slow particle descent by increasing drag and buoyancy. Finally, I will briefly discuss a mathematical model of microbial foraging by particle-hopping, which takes into account the highly stochastic nature of particle foraging and predicts that this copiotrophic behaviour is significantly more widespread than currently thought.
Tuesday, November 4, 2025 • 2:30 PM • Clark 507
Estimating ocean carbon uptake: Global integrals to mCDR additionality
Galen McKinley, Columbia University and Lamont-Doherty Earth Observatory
Since the preindustrial era, the ocean has removed about 40% of fossil CO2 from the atmosphere, and it will eventually absorb at least 80% of human CO2 emissions. At the global scale, three independent approaches—numerical models, machine learning based data products, and interior observations—allow for quantification of the ocean carbon sink of the last few decades to within 25% uncertainty. This impressive agreement is first-order attributable to the strong forcing from rapidly rising atmospheric pCO2. This level of agreement across methods would likely be acceptable if scientific curiosity were the sole motivator. However, since managing the global climate means managing the global carbon cycle, it is critical to further drive down uncertainties. I demonstrate how machine learning can be applied to combine hindcast models with surface ocean pCO2 data, providing improved quantification. I also show how CMIP models can serve as a testbed to identify areas where additional ocean pCO2 observations are most needed. Given the outsized role of the ocean in mitigating anthropogenic CO2 emissions, the concept of engineering marine Carbon Dioxide Removal (mCDR) to enhance the ocean sink is now of great interest. mCDR projects will need to demonstrate that any carbon absorbed is “additional” to what would have occurred without intervention. By comparison to independent observations at 1x1 degree monthly resolution, I illustrate that today’s models and products will need substantial refinement before expected signals from mCDR could be distinguished from the uncertainty of the unperturbed state.
A Zoom link is available for remote participants.
Please Signup for an in-person meeting with Galen McKinley on November 4.