## Tipping Points in Climate Systems

4 March, 2013

If you’ve just recently gotten a PhD, you can get paid to spend a week this summer studying tipping points in climate systems!

They’re having a program on this at ICERM: the Institute for Computational and Experimental Research in Mathematics, in Providence, Rhode Island. It’s happening from July 15th to 19th, 2013. But you have to apply soon, by the 15th of March!

For details, see below. But first, a word about tipping points… in case you haven’t thought about them much.

### Tipping Points

A tipping point occurs when adjusting some parameter of a system causes it to transition abruptly to a new state. The term refers to a well-known example: as you push more and more on a glass of water, it gradually leans over further until you reach the point where it suddenly falls over. Another familiar example is pushing on a light switch until it ‘flips’ and the light turns on.

In the Earth’s climate, a number of tipping points could cause abrupt climate change:

(Click to enlarge.) They include:

• Loss of Arctic sea ice.
• Melting of the Greenland ice sheet.
• Melting of the West Antarctic ice sheet.
• Permafrost and tundra loss, leading to the release of methane.
• Boreal forest dieback.
• Amazon rainforest dieback
• West African monsoon shift.
• Indian monsoon chaotic multistability.
• Change in El Niño amplitude or frequency.
• Change in formation of Atlantic deep water.
• Change in the formation of Antarctic bottom water.

• T. M. Lenton, H. Held, E. Kriegler, J. W. Hall, W. Lucht, S. Rahmstorf, and H. J. Schellnhuber, Tipping elements in the Earth’s climate system, Proceedings of the National Academy of Sciences 105 (2008), 1786–1793.

Mathematicians are getting interested in how to predict when we’ll hit a tipping point:

• Peter Ashwin, Sebastian Wieczorek and Renato Vitolo, Tipping points in open systems: bifurcation, noise-induced and rate-dependent examples in the climate system, Phil. Trans. Roy. Soc. A 370 (2012), 1166–1184.

Abstract: Tipping points associated with bifurcations (B-tipping) or induced by noise (N-tipping) are recognized mechanisms that may potentially lead to sudden climate change. We focus here a novel class of tipping points, where a sufficiently rapid change to an input or parameter of a system may cause the system to “tip” or move away from a branch of attractors. Such rate-dependent tipping, or R-tipping, need not be associated with either bifurcations or noise. We present an example of all three types of tipping in a simple global energy balance model of the climate system, illustrating the possibility of dangerous rates of change even in the absence of noise and of bifurcations in the underlying quasi-static system.

We can test out these theories using actual data:

• J. Thompson and J. Sieber, Predicting climate tipping points as a noisy bifurcation: a review, International Journal of Chaos and Bifurcation 21 (2011), 399–423.

Abstract: There is currently much interest in examining climatic tipping points, to see if it is feasible to predict them in advance. Using techniques from bifurcation theory, recent work looks for a slowing down of the intrinsic transient responses, which is predicted to occur before an instability is encountered. This is done, for example, by determining the short-term auto-correlation coefﬁcient ARC in a sliding window of the time series: this stability coefﬁcient should increase to unity at tipping. Such studies have been made both on climatic computer models and on real paleoclimate data preceding ancient tipping events. The latter employ re-constituted time-series provided by ice cores, sediments, etc, and seek to establish whether the actual tipping could have been accurately predicted in advance. One such example is the end of the Younger Dryas event, about 11,500 years ago, when the Arctic warmed by 7 C in 50 years. A second gives an excellent prediction for the end of ’greenhouse’ Earth about 34 million years ago when the climate tipped from a tropical state into an icehouse state, using data from tropical Paciﬁc sediment cores. This prediction science is very young, but some encouraging results are already being obtained. Future analyses will clearly need to embrace both real data from improved monitoring instruments, and simulation data generated from increasingly sophisticated predictive models.

The next paper is interesting because it studies tipping points experimentally by manipulating a lake. Doing this lets us study another important question: when can you push a system back to its original state after it’s already tipped?

• S. R. Carpenter, J. J. Cole, M. L. Pace, R. Batt, W. A. Brock, T. Cline, J. Coloso, J. R. Hodgson, J. F. Kitchell, D. A. Seekell, L. Smith, and B. Weidel, Early warnings of regime shifts: a whole-ecosystem experiment, Nature 332 (2011), 1079–1082.

Abstract: Catastrophic ecological regime shifts may be announced in advance by statistical early-warning signals such as slowing return rates from perturbation and rising variance. The theoretical background for these indicators is rich but real-world tests are rare, especially for whole ecosystems. We tested the hypothesis that these statistics would be early-warning signals for an experimentally induced regime shift in an aquatic food web. We gradually added top predators to a lake over three years to destabilize its food web. An adjacent lake was monitored simultaneously as a reference ecosystem. Warning signals of a regime shift were evident in the manipulated lake during reorganization of the food web more than a year before the food web transition was complete, corroborating theory for leading indicators of ecological regime shifts.

### IdeaLab program

If you’re seriously interested in this stuff, and you recently got a PhD, you should apply to IdeaLab 2013, which is a program happening at ICERM from the 15th to the 19th of July, 2013. Here’s the deal:

The Idea-Lab invites 20 early career researchers (postdoctoral candidates and assistant professors) to ICERM for a week during the summer. The program will start with brief participant presentations on their research interests in order to build a common understanding of the breadth and depth of expertise. Throughout the week, organizers or visiting researchers will give comprehensive overviews of their research topics. Organizers will create smaller teams of participants who will discuss, in depth, these research questions, obstacles, and possible solutions. At the end of the week, the teams will prepare presentations on the problems at hand and ideas for solutions. These will be shared with a broad audience including invited program officers from funding agencies.

Two Research Project Topics:

• Tipping Points in Climate Systems (MPE2013 program)

• Towards Efficient Homomorphic Encryption

IdeaLab Funding Includes:

• Travel support

• Six nights accommodations

• Meal allowance

The Application Process:

IdeaLab applicants should be at an early stage of their post-PhD career. Applications for the 2013 IdeaLab are being accepted through MathPrograms.org.

Application materials will be reviewed beginning March 15, 2013.

## I’m Looking For Good Math Grad Students

11 December, 2012

I am looking for hardworking math grad students who:

1) know some category theory and ideally a bit of 2-category theory,

2) know some mathematical physics, stochastic processes and/or Bayesian network theory, and

3) want to apply these ideas to subjects like chemistry, biology, ecology and climate science.

If this is you, please email me and/or apply to the math Ph.D. program at U.C. Riverside. To apply, follow the directions here. For more information, go here. The deadline is January 5th.

We have very little money for foreign students, so this advertisement is mainly for students from the US and especially California. If you want to work with me, mention my name in your application.

I can’t promise to work with you, of course, until you’re accepted and I get to know you and decide we can work well together! Luckily there are other good professors in the department doing other interesting things.

I urge would-be students to come to my seminar, which meets once a week, and also my special sessions where we work on projects, which currently also occur once a week. I’ll pick students from among people who do these things. Right now there are 6 candidates. I can’t take this many new students every year, so I’ll pick the ones who show the most initiative and promise.

I’m working on network theory and information theory, and I’m also getting started on climate physics, especially glacial cycles. You can decide if these topics interest you by clicking on the links. I’m not taking students who want to do thesis work on my old interests (quantum gravity and n-categories).

The U.C.R. math building looks 2-dimensional in this shot, but I promise you’ll get a well-rounded education if you work with me.

7 November, 2012

Are you an undergrad who likes math and biology and wants a good grad program? This one sounds really interesting. The ad I bumped into is focused on minority applicants, maybe because U.C. Riverside is packed with students whose skin ain’t pale. But I’d say biostatistics is a good career even if you have the misfortune of needing high-SPF sunscreen:

The Department of Biostatistics, which administers PhD training at the Harvard School of Public Health, seeks outstanding minority applicants for its graduate programs in Biostatistics.

Biostatistics is an excellent career choice for students interested in mathematics applied to real world problems. The current data explosion is contributing to the rising stature of, and demand for biostatisticians, as noted in the New York Times:

I keep saying that the sexy job in the next 10 years will be statisticians … and I’m not kidding.

To date, Biostatistics has not been successful in attracting qualified minority students, particularly African Americans. Students best suited for careers in Biostatistics are those with strong mathematical abilities, combined with interests in health and biology. Unfortunately, statistics is not widely taught at the undergraduate level, and many potentially excellent candidates simply do not learn about the possibility of a valuable and fulfilling career in Biostatistics. Many minority students who could thrive in a Biostatistics program choose instead to enter medical school. Public health in general, and Biostatistics in particular, are not even considered as options. We would like your help in identifying qualified students before they make their choices regarding graduate school or other career paths.

All doctoral students accepted in our department are guaranteed full tuition and stipend support throughout their program, as long as they are making satisfactory progress towards the PhD degree. Every effort is made to meet the individual needs of each student, and to insure the successful completion of graduate work.

The web site for prospective students is here.

Please note the deadline for submitting applications to the MA and PhD programs for entry in the fall of 2013 is December 15, 2012.

We look forward to answering any questions you may have. Questions about our graduate programs can be directed to Jelena Follweiller, at jtillots@hsph.harvard.edu.

## Bioremediation and Ecological Restoration Job

23 October, 2011

The University of Texas – Pan American (UTPA) Department of Biology is trying to fill an Assistant Professor Faculty position in Bioremediation and Ecological Restoration, which will start in Fall 2012 pending budget approval. They’re looking for someone whose area of research is bioremediation and/or ecological restoration, and they’re especially interested in candidates whose research focuses on environmental issues relevant to the Lower Rio Grande Valley.

For more details, go here.

## NSF Funding for Research in Asia

15 September, 2011

The National Science Foundation has a program called EAPSI, which stands for East Asia and Pacific Summer Institutes. This is a program where US grad students are supported to participate in 8-week research experiences at laboratories in Australia, China, Korea, New Zealand, Singapore, Taiwan and Japan (where you actually get 10 weeks). It runs from June to August. The program provides a \$5,000 summer stipend, round-trip airfare to the host location, living expenses abroad, and an introduction to the society, culture, language, and research environment of the host location.

Sounds cool, huh?

The application for the summer of 2012 is now open. It will close at 5:00 pm proposer’s local time on November 9, 2011. Application instructions are available online here. For further information concerning benefits, eligibility, and tips on applying, go here or here.

Since there’s a good chance I’ll be here at the Centre for Quantum Technologies in Singapore for the summer of 2012, I’d love it if you could apply to this program and get a fellowship to work with me. However, I have no idea if this is actually possible! I just learned about this program five minutes ago, and I’ve told you everything I know about it.

Anyway, it sounds like a good thing. I believe the 21st century is the century of Asia. If you’re a grad student in any sort of science, you want to get in on that.

## Environment and Sustainability Institute

30 March, 2011

My friend John Barrett pointed out that the Environmental and Sustainability Institute at Exeter has jobs for mathematicians and statisticians who “combine research expertise in areas such as computational statistics, data modelling, system dynamics, control, optimization and/or computation with vision and innovation so as to transform research across the environment and sustainability agenda”.

I got his email today; the deadline has already passed, but maybe you can slip under the wire:

Professor in Applied Mathematics/Statistics

Ref: R10168

Location: Environment and Sustainability Institute, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Tremough Campus (Cornwall).

Salary: by negotiation, generous holiday allowances, flexible working, pension scheme, car lease scheme and relocation package.

We are taking a unique opportunity to create a world-leading, interdisciplinary centre investigating the consequences of environmental change and the mitigation and management of its effects. Building on the existing academic strengths of the University of Exeter, the 30 million pound Environment and Sustainability Institute (ESI) will focus on undertaking significant cutting-edge research in finding solutions to problems of environmental change, and the application of an ecosystem services approach. There will be three major themes: Clean technologies, Natural environment, and Social science. The initiative is funded with a 22.9 million pound investment from the European Regional Development Fund and 6.6 million pounds from the South West of England Regional Development Agency.

We are looking for research leaders in Applied Mathematics and/or Statistics who will combine research expertise in areas such as computational statistics, data modelling, system dynamics, control, optimization and/or computation with vision and innovation so as to transform research across the environment and sustainability agenda. Applicants will have a strong track record of research funding and international quality publications, together with proven ability in teaching and curriculum development.

Applicants are encouraged to contact the Dean of the College, Prof Ken Evans to discuss the posts further. Informal enquiries can be made to Prof Peter Ashwin You may also wish to consult our web site for further details of the College.

The full range of necessary skills and experience can be found in the Job Description and Person Specification document.

Your full academic CV should be accompanied by a short letter of application explaining why you are interested in the post.

The University of Exeter is an equal opportunity employer which is ‘Positive About Disabled People’. Whilst all applicants will be judged on merit alone, we particularly welcome applications from groups currently under-represented in the workforce.

## Summer Program on Climate Software

3 March, 2011

Here’s a great opportunity if you’re a student looking for something to do this summer. The Climate Code Foundation is working on open-source versions of important climate software. If you’re lucky, you could get paid to help!

• Climate Code Foundation, Google Summer of Code.

It seems the window for student applications is March 28-April 8.

They write:

Google have announced their Summer of Code, and we intend to be a mentoring organisation. If you’re a student, this is an opportunity to work on our open source code and earn a bit of money doing so (Google give a stipend of USD 5000 qualifying students, and an honorarium of USD 500 to the mentoring organisation).

We have an ideas page, most of which revolves around our ccc-gistemp project. Ideas range from improving ccc-gistemp in various ways, through novel reconstructions, to clear implementations of other climate codes. If you have ideas of your own, we’d like to hear about those too.

If you are interested in participating as a student, then please get in touch.

We have not been a Summer of Code mentor before, but we bring many years (decades even!) of experience to the table: experience in computer science, software engineering, project management, and so on. We hope to help students make a success of their projects!

In case you’re wondering, ccc-gistemp is a version of GISTEMP written in Python.

Isn’t it annoying how explaining one mysterious word can require two more? In case you’re still wondering: Python is a really groovy modern programming language, in comparison to older ones like FORTRAN—and GISTEMP is an important computer program, mostly written in FORTRAN, which NASA uses to analyze the historical temperature record. GISTEMP is what gives us graphs like this:

So, it’s very important to update this program and search the existing program for bugs—and that’s what the Climate Code Foundation is doing:

The “all Python” milestone was achieved with ccc-gistemp release 0.2.0 on 2010-01-11. Naturally we have found (minor) bugs while doing this, but nothing else. Since 0.2.0 we have made major simplifications, chiefly by removing dependencies, and generally processing data internally (by avoiding writing it to intermediate files, which was only necessary on computers that would be considered extremely memory constrained by today’s standards).

Work continue on further simplification, clarification, generalisation, and extension.

Hone your programming skills while helping save the planet!