#goldschmidt2021 We contribute our work on dissipative dynamics and frequency distributions in river geochemistry and an update on the thermodynamics of planetary evolution.

Our work on thermodynamics and the Goldschmidt conference on geochemistry – well, that seems like an obvious match. But what we contribute is a little different, and the match is not quite so straightforward. What our perspective adds is (a) a focus on non-equilibrium thermodynamics and disequilibrium, and the processes that generate and dissipate this disequilibrium, and (b) a system‘s view which accounts for the environmental setting as well as the interactions and feedbacks within the Earth as an overarching thermodynamic system. Both of our contributions next week nicely illustrate these points and show how important it is to think „thermodynamics“ beyond its more narrow application to geochemical reactions.

Roberta, a PhD student from the University of Florence, presents our joint work with her advisor, Antonella Buccianti, as well as her colleagues at the Univ. of Florence on finding the answer to Is the dissipative behavior of river chemistry and catchment weathering dynamics reflected in their frequency distributions? in session „9k – Critical zone processes across space and time“. This question is motivated by the frequency distributions of geochemical elements, which often either show a normal or log-normal distribution, or a power-law distribution. How is the type of the distribution related to the thermodynamics of the system, particularly whether it is a dissipative system, or a system close to equilibrium? Roberta used extensive geochemical samples from the Arno river basin in central Italy, related it to the non-equilibrium thermodynamics of river water mixing, and found some really interesting results. Her presentation takes place on Monday, 5 July 2021, 17:10 in Room 04 (online). Her work is ready for write-up, so there’ll be more on this soon, in form of a manuscript and, hopefully, another blogpost.

Axel presents an update of the joint work with Adam Frank (Univ. Rochester) and Marina Alberti (Univ. Washington) on Thermodynamics of the planetary transitions from barren worlds to habitability and advanced technological societies in session „8f – Understanding the co-evolution of Earth’s interior, its surface, and its microorganisms„ (originally, it was submitted to a session on the Anthropocene, but apparently, this session got merged). This work is based on our paper Frank et al. (2017), which describes a basis to distinguish different planets regarding their processes that perform work and generate free energy, which reflects different forms of thermodynamic disequilibrium, and which results in different, dissipative dynamics, including human societies. This framework is currently extended to describe the general dynamics of such processes, the feedbacks involved, and how this links to concepts such as habitability and carrying capacity. His presentation is scheduled for Friday, 9 July 2021, 09:00 in Room 11 (online). More on this should come out sometime soon in form of a manuscript.

#vEGU21 Next week we’ll present our work on precipitation scaling, diurnal temperature range, offshore wind, and limits to vegetation productivity based on our thermodynamic Earth system view

Thermodynamics rules the world, as well as the science that we present at this year’s EGU General Assembly, which is, alas, virtual rather than in Vienna. It may not be obvious, and our contributions are spread across different sessions. But in the end, we follow the solar energy as it passes through the Earth system, seeking simple, physics-based explanations to simple phenomena: precipitation scaling with temperature found in observations, the diurnal temperature range across regions and vegetation types, also in observations, limits to offshore wind energy in the North sea and what these imply for renewable energy scenarios, and how the really low efficiency of photosynthesis fits to the notion of vegetation being optimal.

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Why does wind energy become less efficient when used at larger scales? Basic physics explains this effect, starting with a very limited ability of the atmosphere to generate wind energy from radiation, as described in my new review just published.

Wind energy plays an important role in the transition to a carbon-neutral, sustainable energy system and is rapidly expanding. So it is a good time to ask how much wind energy there actually is, whether we get close to the limits anytime soon, and why the efficiency of wind energy must decline when used at larger scales. These are basic science questions: How, and why, does the atmosphere actually generate motion, how much does it generate, and how much of it can at most be used? These questions I address in a review paper just published in which I show that it does not take much physics to answer these.

Continue reading “Why does wind energy become less efficient when used at larger scales? Basic physics explains this effect, starting with a very limited ability of the atmosphere to generate wind energy from radiation, as described in my new review just published.”

Does thermodynamics limit photosynthesis? It probably does, but not as you may think

Fig Leaf picturePhotosynthesis is the process which powers life on Earth.  It takes the energy contained in sunlight, uses carbon dioxide, and generates chemical energy that is stored in form of sugars and similar compounds that fuel the activity of the biosphere, including us humans.  And just as any other Earth system process, in doing so it follows the laws of thermodynamics.  But does thermodynamics also restrict the efficiency by which photosynthesis can use sunlight? 

Continue reading “Does thermodynamics limit photosynthesis? It probably does, but not as you may think”