Summary Report No. 14


TOYS - Materials to the Brandenburg biosphere model / GAIA
Part 1 - Simple models of the Climate and Biosphere system

Yu. Svirezhev (ed.), A. Block, W. v. Bloh, V. Brovkin, A. Ganopolski, V. Petoukhov, V. Razzhevaikin (January 1996)

Yu. Svirezhev: Introduction

Yu. Svirezhev: 1. Model description and basic equations

V. Petoukhov: 2. Parametrization of outgoing longwave radiation flux to be used in 0-dimensional "Climate-Biosphere model"

Yu. Svirezhev and W. von Bloh: 3. Interaction between climate and vegetation: "one causal loop" partial case

V. Razzhevaikin: 4. Qualitative effects in the spatially structured model temperature - biota

Yu. Svirezhev and W. von Bloh: 5. Climate, vegetation and global carbon cycle: "two causal loops" partial case

A. Block, W. von Bloh, A. Ganopolski and V. Brovkin: 6. Geophysiological modelling of climate-biosphere interaction

Yu. Svirezhev: Conclusion: Toys and Realities

The Climate Change Problem is very fashionable today. A huge amount of publications mask (and very successfully) one simple fact, that we ourselves can hardly conceive

• how the "Biosphera machina" operates, or

• whether our Earth Biosphere is unique or whether any other virtual biospheres exist.

In order to answer these questions, we consider the system "biosphere + climate" as a nonlinear system with multiple equilibria. Note that in considering this problem we shall remain within a framework of the most simple zero-dimension and one-dimension models.

The development and realization of these ideas are presented in the chapters 1-5.

Figure 1: Bifurcation diagram. The contemporary Earth Biosphere is one of many possible (virtual) biospheres, corresponding to the multiple equilibria of some nonlinear dynamic system "climate + biosphere". In the course of planetary history and proper evolution this system has passed through several bifurcation points, when random perturbations determined on which branch of the solution the system would appear.

Figure 2: Phase portrait of the climate-vegetation model containing a carbon cycle. The filled circles represent stable equilibria of the system while the other circle indicate unstable nodes. The different coloured areas are the domain of attractions of the three different stable equilibria "cold desert", "cold planet", and "hot planet".

Lovelock & Watson (1983) in their Daisy world scenario formalized the Earth description as self-organized system with equilibrium of flows of energy and matter. This model is usually classified as a geophysiology approach. In the chapter 6, the original Daisy world model is extended in some important aspects and concretized to cover realistic biosphere-climate interaction in its structural and functional behaviour. The structural stability, elasticity, regulation ability, and behaviour of the biosphere-climate system under external perturbations have been studied for zero- and one-dimension models.

The Daisy World PIK Page