Announcing a Special Issue on Managing Nonlinear Climate Risk

I am guest editor for a Special Issue on “The Implications of Nonlinear, Complex System Behaviour for Managing Changing Climate Risk” that will appear in the MDPI AG journal Atmosphere. Researchers, policymakers and practitioners are invited to submit a paper for consideration to this special issue.

With the IPCC Sixth Assessment Report in its early stages, there is a very limited literature on managing the risk of nonlinear climate change on decadal timescales, yet nonlinear change poses a much greater risk than gradual change. If climate change on decision-making timescales proves to be fundamentally nonlinear, as we maintained in a paper published earlier this year, there will be a substantial gap in the assessment. This special issue invites submissions on all aspects of the implications of nonlinear climate change for risk management, from theory through to practice.

More details can be found at:
http://www.mdpi.com/journal/atmosphere/special_issues/nonlinear_climate_risk (link)

 

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Trolling. It’s more important now than ever.

When contrarian commentator Bret Stephens was hired by the New York Times as a columnist, there was an immediate outcry from climate scientists and the pro-climate policy community. Some cancelled their subscriptions:

Why I cancelled my @nytimes subscription. @BretStephensNYT pic.twitter.com/A3lFZNJdhY

— Stefan Rahmstorf (@rahmstorf) April 27, 2017

Stephens had been on record as describing climate change as an ‘imaginary enemy’. The timing was odd. NYT has just hired a high-profile climate team and was selling itself with the slogan “Truth. It’s now more important than ever.”

Credit: Think Progress for the link. Ad from The New York Times’ marketing campaign. Credit: The New York Times via AdAge

The hire was defended by James Bennet, editorial page editor:

Step change hypothesis and working paper

Imagine you didn’t know anything about climate change and the greenhouse effect but were interested and you know a bit about general science. Would you accept the following story?

“Earth’s climate is a large, complex system, affected by forces that produce both linear and nonlinear responses. Shortwave radiation – basically UV – from the sun comes in and heats up the planet, producing infrared radiation. Some UV gets reflected straight back out by clouds, snow and ice and stuff. The land can heat up quite a lot, but it cools back down again and doesn’t store much. If a forest is cleared and replaced by buildings, it will warm up a bit but the effect is only local.”

“But the ocean – that’s another story. It absorbs a lot of radiation, so is taking up heat all the time. Huge streams of energy are entering and leaving the ocean store each year. Some is ‘dry’ or sensible heat, which is ordinary warmth. Some is ‘wet heat’ or evaporated moisture. Energy gets taken up when the moisture is evaporated and it will be released again when the moisture cools, condenses and then gets rained out. In this way, the oceans provide a lot of heat to the land every year, largely as rainfall and a bit of snow.”

But is it just red noise?

I gave a seminar yesterday at the ARC Centre of Excellence for Climate System Science at the University of New South Wales. Thanks Alvin Stone and Andrea Taschetto for organising it. It’s the first time I’ve had the opportunity to go through the entire ‘step change’ hypothesis of how the climate changes, the theoretical background, structural models developed from that and how the testing was set up, prior to showing a whole raft of test results.

One of the questions I got at the end, which also comes up quite often in the literature, was about the potential cause of the step changes in temperature data. It came from a question as to whether we had tested the step change model with artificial data that had been ‘reddened’ – that is, made dependent on the previous data. Such time series can have long-term persistence and contain a number of different quasi-periodic timescales, so do not conform to a single statistical model. This line of questioning alludes to whether a step or nonlinear response in a time series needs to be have an underlying cause that can be linked to an external source or whether it’s the result of random variations (see paper by Rodionov for a more more technical description). I gave a somewhat flip answer – because there is real energy in the system we are assessing (the climate system), whether a rapid shift is due to red noise or not matters less than understanding what that means for risk.

End of the hiatus

Understanding Climate Risk has been in something of a hiatus, or a pause for the last couple of years due your host being almost fully submerged, but maybe it’s time to rise to the surface and get things going again.

This is for a few reasons. One is that research, especially public good research and especially in CSIRO, is under serious threat in Australia. We have a government who tout innovation, but who wilfully ignore the role of the generation of underpinning knowledge in fuelling such innovation. They are interested only in commercial innovation – public-good innovation is not only being ignored, it is being excluded from processes such as the Cooperative Research Centre bids currently under way. Having sustainable cities, catchments and ecosystems is impossible without public good research and social innovation, with funding that extends across the sciences, the humanities and the arts. With an election going on, these harms need to be publicised.

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Empirical evidence disproves, no less! What ho! Egads! Science crumbles in the face of such devastating analysis. There are so many zingers here that Bill Shortninbread should look out.

And now, read on…

Pell hoists himself on his own logic

We have been waiting for Cardinal George Pell to comment publicly on Pope Francis’ encyclical Laudato Si’ because it professes pretty much the opposite to Pell’s public omnipotence on all things climate change.

Speaking to the Financial Times in a story on his reform of Vatican finance, Pell says this:

“It’s got many, many interesting elements. There are parts of it which are beautiful,” he says. “But the church has no particular expertise in science . . . the church has got no mandate from the Lord to pronounce on scientific matters. We believe in the autonomy of science,” added Cardinal Pell.

New IPCC report: busting myths, both scientific and economic

By Roger Jones, Victoria University

The headline statements of the Intergovernmental Panel on Climate Change’s new Synthesis Report – unequivocal climate change, almost certainly driven largely by humans, and an urgent need to cut emissions – won’t come as any surprise to people who paid attention to the three larger reports the IPCC has released over the past 14 months.

But reading the full synthesis report, as opposed to the shorter Summary for Policymakers (SPM), shows that while the facts haven’t changed, the IPCC has subtly altered its approach to how it presents this information. Instead of dealing largely in forecasts and responses, as in previous syntheses, it now frames the climate problem squarely in terms of risk management.

Not everything of importance in the full synthesis report made it into the SPM. The language in the SPM is also weaker, particularly about the nature of irreversible risks and about threats to food security. The full report contains valuable pointers for managing climate risks and the benefits of acting, so should be preferred for decision-making purposes.

The report is also great for debunking some of the persistent myths about climate change, both scientific and economic. But, unfortunately given the urgent need for new economic policy to cut carbon, it’s stronger on the former than the latter.

Pentagon adapts

The US Department of Defense has just released their FY 2014 Climate Change Adaptation Roadmap, Secretary Chuck Hagel saying in the foreword “Politics or ideology must not get in the way of sound planning.”

The Department has established three broad adaptation goals:

Goal 1: Identify and assess the effects of climate change on the Department.

Goal 2: Integrate climate change considerations across the Department and manage associated risks.

Goal 3: Collaborate with internal and external stakeholders on climate change challenges.

These goals are supported by four lines of effort:

1. Plans and Operations include the activities dedicated to preparing for and carrying out the full range of military operations. Also included are the operating environments in the air, on land, and at sea, at home and abroad, that shape the development of plans and execution of operations.
2. Training and Testing are critical to maintaining a capable and ready Force in the face of a rapidly changing strategic setting. Access to land, air, and sea space that replicate the operational environment for training and testing is essential to readiness.
3. Built and Natural Infrastructure are both necessary for successful mission preparedness and readiness. While built infrastructure serves as the staging platform for the Department’s national defense and humanitarian missions, natural infrastructure also supports military combat readiness by providing realistic combat conditions and vital resources to personnel.
4. Acquisition and Supply Chain include the full range of developing, acquiring, fielding, and sustaining equipment and services and leveraging technologies and capabilities to meet the Department’s current and future needs, including requirements analysis.

It’s a sensible and clearly articulated road map that outlines the complexity of operating a large agency in increasingly complex settings. Go read. It’s the kind of planning we need in Australia – instead we have ideologically-induced paralysis.

‘Wait and see’ on climate? No, the science is clear: act now

By Roger Jones, Victoria University and Roger Bodman, Victoria University

When should we act to reduce our greenhouse gas emissions and tackle climate change: now, or later when we know more?

One person who thinks we should wait is New York University theoretical physicist, and former US Under Secretary of Energy for Science, Steven Koonin.

In an article published by the Wall Street Journal, and reproduced in The Australian, Koonin claims that climate models are still too uncertain and that everyone should hold their horses, arguing that:

… because the natural climate changes over decades, it will take many years to get the data needed to confidently isolate and quantify the effects of human influences.

That’s not to say that the issue isn’t pressing. But Koonin says we should urgently do science, rather than urgently cut emissions:

The science is urgent, since we could be caught flat-footed if our understanding does not improve more rapidly than the climate itself changes.

Well, yes. But we’ve been doing this “urgent science” for decades.