Thursday, 20 March 2014

Early Warning Signal & Critical Tipping Points discussion

The CTHULHU group's been quiet so far this year, so I thought I'd let you all know about an upcoming Palaeo group journal discussion session on Early Warning Signals I'm hosting that you may be interested in. It'll be (palaeo)climate focused but we'll be discussing the general theory of EWS and critical transitions too.

It's next
Thursday 27th March at 11:30 in room 064/03, the blurb is attached below (along with the papers):

"This week we'll be discussing the emerging use of 'Early Warning Signals' (EWS) analysis in Palaeo and Modern climate datasets.

Detecting EWS in modern climate (and other environmental) data promises to offer the ability to predict the approach of future tipping points. This approach also offers the ability to test the presence of tipping points hypothesised to have been passed during various palaeoclimate events. However, the statistics involved are complex and can be sensitive to parameter choices, and not all tipping points might yield EWS. As the analysis of EWS and other tipping point indicators becomes more common it is imperative that palaeo researchers at least broadly understand their use and limitations as hypothesised palaeoclimatic critical transitions are put to the test.

We'll primarily be discussing the Dakos et al. (2008) PNAS article which analyses several palaeo events and models, while two other slightly longer reviews of the use of EWS in Palaeo & Modern climate studies (Lenton, 2011) and across all fields (Scheffer et al, 2009) are also provided for background reading."

Hope to see some of you there!

Thursday, 27 June 2013

Paper discussion: "The Emergence of Environmental Homeostasis in Complex Ecosystems"

The CTHULHU* discussion group will be meeting this coming Wednesday 3rd July to discuss the recent paper "The Emergence of Environmental Homeostasis in Complex Ecosystems" with James Dyke, one of the paper's authors. We'll be meeting at 1pm in the Ray Beverton room (044/11) at NOCS.


The Earth, with its core-driven magnetic field, convective mantle, mobile lid tectonics, oceans of liquid water, dynamic climate and abundant life is arguably the most complex system in the known universe. This system has exhibited stability in the sense of, bar a number of notable exceptions, surface temperature remaining within the bounds required for liquid water and so a significant biosphere. Explanations for this range from anthropic principles in which the Earth was essentially lucky, to homeostatic Gaia in which the abiotic and biotic components of the Earth system self-organise into homeostatic states that are robust to a wide range of external perturbations. Here we present results from a conceptual model that demonstrates the emergence of homeostasis as a consequence of the feedback loop operating between life and its environment. Formulating the model in terms of Gaussian processes allows the development of novel computational methods in order to provide solutions. We find that the stability of this system will typically increase then remain constant with an increase in biological diversity and that the number of attractors within the phase space exponentially increases with the number of environmental variables while the probability of the system being in an attractor that lies within prescribed boundaries decreases approximately linearly. We argue that the cybernetic concept of rein control provides insights into how this model system, and potentially any system that is comprised of biological to environmental feedback loops, self-organises into homeostatic states.

Dyke, J. G. & Weaver, I. S. The Emergence of Environmental Homeostasis in Complex Ecosystems. PLoS Computational Biology 9, e1003050 (2013).

Wednesday, 9 May 2012

First meet-up: Monday 14th, 3pm, PG Lounge!

Our first meet-up is scheduled for this coming Monday (the 14th) at 3pm in the PG Lounge, where we'll be having an informal chat about the group and what plans there are supported by CTHULHU-themed cakes & coffee - if you're interested in the group then come along if you can! 

Thursday, 1 March 2012

Introducing CTHULHU: The Complex earTH system nUmerical modeLling and pHysical Understanding discussion group!

Are you interested in the application of systems and complexity theory in Ocean and Earth sciences? Involved in Earth system modelling and in need of friendly discussion and advice? Want to pay homage to an ancient water god capable of fiery destruction in an informal and caffeinated atmosphere? Then the CTHULHU discussion group is for you!
We are a newly set up informal group based at NOCS who plan to come together for occasional discussions, talks and coffee drinking sessions in order to share ideas and advice in all things Earth Systems. We hope that through CTHULHU that we can help each other in research relating to complex systems in Earth & Ocean science, and have a good time whilst we're at it.

All students and staff are welcome to join in, and we also hope to help increase 'interdepartmental synergy' between NOCS, the Institute for Complexity Systems Simulations (ICSS) at Highfield and with any other students & staff interested across the University (and beyond).

If you'd like to join the mailing list to hear about upcoming meet-ups and events then email – we look forward to kicking it all off very soon!

Some useful linkies for more information:
CTHULHU mailing list / blog home:
A vague definition of Earth Systems Science:
More on our patron, the great and wrathful Cthulhu: