Category: Science

New Book Chapter:  Understanding the Earth as a Whole System: From the Gaia Hypothesis to Thermodynamic Optimality and Human Societies

~ Axel Kleidon ~ Leave a comment

“The whole is more than the sum of its parts” – this has been said by smart people throughout human history, from Aristotle to Gibbs.  But how does it apply to the vastly complex Earth system?  In the book chapter just published I describe how this focus on the whole combined with a thermodynamic formulation of the Earth system including life helps us to understand that the whole is more, and simpler, than the sum of its parts.  This is because complex, natural systems appear to work at their thermodynamic limit.  The emergent functioning may then very well share characteristics similar to those postulated by the controversial Gaia hypothesis of James Lovelock, which states that life regulates the Earth for its own benefit.

Continue reading “New Book Chapter:  Understanding the Earth as a Whole System: From the Gaia Hypothesis to Thermodynamic Optimality and Human Societies” →
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New Blogpost: How much energy will I consume to keep our home warm this winter? A simple estimate, utilizing climate data, gas meter readings, and past gas bills. And yes, the second law comes into play as well.

~ Axel Kleidon ~ Leave a comment

Winter is coming, snow is falling, and here in Jena we will need gas to heat our homes. Gas prices are at their all-time high, so how much heat do I need and how can I reduce it? I describe a simple, physical way to estimate how much energy I should need to heat our home, and how this can help to find out how effective measures are to reduce energy consumption.

Continue reading “New Blogpost: How much energy will I consume to keep our home warm this winter? A simple estimate, utilizing climate data, gas meter readings, and past gas bills. And yes, the second law comes into play as well.” →

Can we infer rainfall sensitivity to global warming using observations of precipitation and temperature? Not quite, until you correct for the cooling effects of clouds.

~ saroshalam ~ Leave a comment

Rainfall events are expected to become heavier as the hydrologic cycle intensifies with global warming. To determine this strengthening, many studies use observed precipitation events and test how these change with observed temperatures. These so-called scaling rates differ from what is expected from theory, showing a decline above temperatures of around 23° – 25°C. This breakdown in scaling makes it difficult to interpret the precipitation response to global warming and its cause further remains unclear. It also raises the question of whether a high-temperature threshold limits the increase in the intensity of precipitation events with temperature. We resolve this in our latest paper by showing that the break in scaling primarily occurs due to radiative effect of clouds on surface temperatures that leads to a covariation between the two variables.

Continue reading “Can we infer rainfall sensitivity to global warming using observations of precipitation and temperature? Not quite, until you correct for the cooling effects of clouds.” →

How much does evaporation affect temperature variations during the day?  That’s what we looked at in a paper just published online in the Journal of Climate.  @annuPanwar_sci @ametsoc @MPI_BGC

~ Axel Kleidon ~ Leave a comment

Over land, there is a marked variation in surface and air temperature during day and night, with the amplitude described by the diurnal temperature range.  What are the main factors that determine its magnitude across regions and how much is it shaped by evaporation?  This is what Annu Panwar looked at in her last part of her PhD using FluxNet observations and the ERA 5 reanalysis products, with the results just published online in the Journal of Climate. What this analysis shows is that energy balances go a long way to explain the main influences and that evaporation does not have quite such a strong effect as one may think.

Continue reading “How much does evaporation affect temperature variations during the day?  That’s what we looked at in a paper just published online in the Journal of Climate.  @annuPanwar_sci @ametsoc @MPI_BGC” →

“Kraftwerk Erde: Wie der belebte Planet Energie umwandelt” – Vortrag bei #FasziAstroOnline, heute Abend, 13.01.2022, 19 Uhr, live auf youtube.  Mehr Infos im Blog. @MPI_BGC @HdAstro

~ Axel Kleidon ~ Leave a comment

Die Erde arbeitet wie ein Kraftwerk, indem sie Sonnenenergie in andere Formen umwandelt, die die Winde der Atmosphäre, den Wasserkreislauf, und auch das Leben und die Menschheit auf der Erde erhalten.  Diese Umwandlungen folgen den Gesetzen der Thermodynamik, die sowohl die Richtung als auch die Grenzen setzt.  Aber Erdsystemprozesse beeinflussen sich auch gegenseitig, sodass man einen Blick auf das Gesamtsystem braucht.  In diesem Vortrag zeige ich, dass man allein durch diesen grundlegenden physikalischen Ansatz schon erstaunlich viel vom Erdsystem verstehen kann – über die fundamentalen Rolle von Energie und Entropie, wie Leben den Planeten verändert, aber auch zu angewandten Themen wie dem Klimawandel und warum die Photovoltaik die Technologie ist, die bei weitem den größten Beitrag zur Energiewende liefern wird.

Continue reading ““Kraftwerk Erde: Wie der belebte Planet Energie umwandelt” – Vortrag bei #FasziAstroOnline, heute Abend, 13.01.2022, 19 Uhr, live auf youtube.  Mehr Infos im Blog. @MPI_BGC @HdAstro” →

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

~ Axel Kleidon ~ 1 Comment

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.

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

If you think surface and air temperature are basically the same thing, think again. Or read our new paper.

~ Axel Kleidon

In meteorology, air temperature measurements are typically taken 2m above the surface.  It is a routine measurement at weather stations, and this temperature is the basis for analyzing trends, such as global warming.  The temperature of the surface is not so often measured, but it can be inferred by satellites from how much radiation is being emitted by the surface.  Being only 2m apart, one may think that the temperatures basically reflect more or less the same, given their close proximity. We actually found out that this is not the case: surface temperature responds much more strongly to a lack of water than air temperature.  This finding was just published in our article in the journal Geophysical Research Letters. Continue reading “If you think surface and air temperature are basically the same thing, think again. Or read our new paper.” →