Understanding Climate Risk

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Archive for the ‘IPCC’ Category

McLean follow up

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Elaine McKewon book-ended my letter to the editors of Fairfax papers The Age and Sydney Morning Herald regarding the publishing of John McLean’s error-ridden piece on the IPCC (the editors, by the way, have not responded) with a terrific take down of McLean in Crikey.

She questioned McLean’s byline on the original article, to whit:

John McLean is the author of three peer-reviewed papers on climate and an expert reviewer for the latest IPCC report. He is also a climate data analyst and a member of the International Climate Science Coalition.”

asking “But is that accurate? Who is John McLean? What qualifications entitle him to speak as an expert on climate science? What is the ICSC, and which groups, interests and agendas do McLean and the ICSC represent? What exactly does it mean to be an “expert reviewer” of IPCC reports?”

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How to read an IPCC report

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By Roger Jones, Victoria University and Celeste Young, Victoria University

The Intergovernmental Panel on Climate Change (IPCC) is the accepted global authority on climate change. It produces reports that are collectively agreed assessments of the scientific literature by leading researchers. The Fifth Assessment Report (AR5) is being delivered over 2013–2014, starting this weekend.

What an IPCC report is

An Intergovernmental Panel on Climate Change (IPCC) report is an assessment that collects and summarises current knowledge in relation to climate change. This is done using literature from peer reviewed and unreviewed (grey) sources.

It is considered the leading review globally of climate change and is produced by a team of hundreds of scientists and specialists from a diverse range of disciplines.

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Time to stop hiding behind warming trends

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Time to stop hiding behind warming trends

By Roger Jones, Victoria University

Dr Rajendra Pachauri, head of the IPCC, has reportedly acknowledged to Graham Lloyd of The Australian, that there is a “17-year pause in global temperature rises”, a fact that apparently has been suppressed in Australia. Dr Pauchauri endorses debate, saying that people had a right to question the science, whatever their motivations.

But according to Lloyd, Pachauri’s views contrast with arguments in Australia that views outside the orthodox position of approved climate scientists should be left unreported.

Am I an “approved” climate scientist? because I don’t hold that view, nor do I know any who does. What we would like, though, is for science to be reported as science and for opinion to be reported as opinion. And for all reporting to be accurate.

Lloyd makes this claim: unlike in Britain, there has been little publicity in Australia given to recent acknowledgement by peak climate-science bodies in Britain and the US of what has been a 17-year pause in global warming. Britain’s Met Office has revised down its forecast for a global temperature rise, predicting no further increase to 2017, which would extend the pause to 21 years.

This is the Met Office’s latest five-year forecast shown below. Skeptical Science reports the Met Office saying: the latest decadal prediction suggests that global temperatures over the next five years are likely to be a little lower than predicted from the previous prediction issued in December 2011. We’re in the midst of a period of La Niñas, which have a slight cooling effect, as do rising sulphate emissions in Asia. But look at the blue line – do my eyes deceive me? Is it level with the previous black line? It’s warmer? Perhaps Lloyd’s computer has a tilt to the right that makes increases look level.


Observed (black, from Hadley Centre, GISS and NCDC) and predicted global average annual surface temperature difference relative to 1971-2000. Retrospective predictions starting from June 1960, 1965, …, 2005 are shown as white curves, with red shading representing their probable range, such that the observations are expected to lie within the shading 90% of the time. The most recent forecast (thick blue curve with thin blue curves showing range) starts from November 2012. All data are rolling annual mean values. The gap between the black and blue curves arises because the last observed value represents the period November 2011 to October 2012 whereas the first forecast period is November 2012 to October 2013. UK Met Office

The Met Office predicts record global mean temperature over the next five years – now that’s news.

News Corporation sells roughly 70% of the newspapers in metropolitan Australia, and its readers are subject to this kind of fudging on a regular basis. It’s no wonder some “approved” scientists are frustrated.

But that’s not the only thing that frustrates me. It is also time to challenge what Lloyd calls the orthodox position of climate science.

Climatology needs to stop hiding behind long-term trends and explain what is in plain sight, and why variations in the rate of warming might be important. I’m working with colleagues at the moment on a National Climate Change Adaptation Research Facility project called Valuing Adaptation to Rapid Change and we’re looking at the economics of rapid change. Non-linear behaviour in climate driving extreme events has the potential to really hurt us.

The first thing to bear in mind is that a trend line is a model. A warming trend is not a theory of how climate changes. If a complex, non-linear system fails to follow a trend, look at the model to see whether it represents the theory sufficiently well.

In a nutshell, the theory says greenhouse gases act like a blanket, trapping heat near the surface. This creates a radiation imbalance at the top of the atmosphere. The earth system warms to return this balance by increasing the heat escaping from the top of the atmosphere so that energy out equals energy in. This is a slow process, taking centuries, because the ocean has to warm sufficiently to support a hotter atmosphere. The scientific confidence in this aspect of climatology is extremely high. A simple trend line is sufficient to measure this process.

But on decadal time scales, the trend-line model fails. Most of the heat trapped in the earth system goes into the oceans. The top 700m of ocean increased in heat content from 3 x 1022 Joules in 1997 to 10 x 1022 Joules in 2010, in a highly non-linear manner, due to mixing rates between the surface and deep ocean. The atmosphere holds as much heat as the top 3m of ocean, about 0.4% of the heat content above. Why on earth then, with highly non-linear processes in the ocean, would we expect a gradual warming trend in the atmosphere?

A paper I published last year shows that most of Australia’s warming occurred in two episodes, one in the late 1960s to early 1970s, when south west WA rainfall also decreased, and the other in 1997-98. The other finding was that most of this warming was anthropogenic. On decadal timescales, step and trend is a much better model for explaining warming than simple trends.

To me, the graph above makes perfect sense: mild trends separated by an instantaneous rise of about 0.3°C. By ignoring non-linearity and projecting future climate change as simple trends, orthodox science is doing us a great disservice. We have not yet woken up to the recent non-linear increases in heatwaves and fire danger in Australia let alone planning for more such changes in the future. The same goes for floods.

Observed and projected percentage area experiencing an exceptionally hot year: Queensland as an example. Note the recent rapid increase (source: K. Braganza, Bureau of Meteorology)

Days above high fire danger, average of 9 Victorian sites, showing statistically significant rapid increase (site data from Bureau of Meteorology)

It’s time to stop defending orthodox science by hiding behind simple trends and come to grips with the fundamental non-linearity of climate change. That’s the risk we need to mitigate, adapting to changes that can’t be avoided.

Roger Jones receives funding from the National Climate Change Adaptation Research Facility. He is affiliated with Climate Scientists Australia and the IPCC.

The Conversation

This article was originally published at The Conversation.
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Spooner’s war on climate policy

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John Spooner, cartoonist for The Age has fired his latest salvo in his war on climate policy in yesterday’s (7-7-2012) paper. It mentions me so I feel obliged to provide a response. J’accuse Spooner of being a propagandist.

Illustration: John Spooner

Yep, that’s me down by the *. Quoted as measuring Australia’s policy impact as being 0.0038°C in 2100. Which would happen if Australia was to reduce its emissions by 5% from 2000 by 2020 and maintain that until 2100. But is this cartoon an accurate and amusing reflection of the conversation Gillard would have with her imaginary friend? Well yes, until the fourth panel. Then it falls away — and that’s worth a bit of scrutiny. And he gets IPCC wrong. What is the IPPC? Read the rest of this entry »

Full IPCC SREX Report Released

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The full IPCC Special Report Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) has been released. The download of the entire report (44 Mb) is here, the Summary for Policymakers is here, the press release is here and slide presentation (pdf) here. Also on the site are individual chapters for download, review comments, process information, graphics and the grey literature library.

As I posted late last year with the release of the SPM, the great benefit of this special report is the coming together of the climate change and disaster management expert communities. A marriage, which I’m told, got a bit rocky at times. The report emphasises the need to address both biophysical and social-economic aspects of changing climate extremes and the systems exposed to those changes. Read the rest of this entry »

Written by Roger Jones

March 30, 2012 at 10:49 am

Climategate V2 emails: exchange on the extremes Table 3-10 in the IPCC TAR

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The second tranche of emails stolen from the University of East Anglia’s Climate Research Unit’s servers has been released by a group who are trying a Wikileaks take on how climate science is done. Last time, given their origin, I wouldn’t have anything to do with them. Now it is claimed there are some 200,000 emails in the database, so their likelihood of eventually being made public is pretty high. The latest 5,000 were selected on specific keywords but beyond that are random. Given that likelihood, the way that science is being challenged on “free” speech grounds by opponents of specific scientific findings, and the need to acquaint the wider public with how science is put together, it seems worth illustrating some of those exchanges in full. This is also to counter the egregious quote mining, out-of-context selection and revivification of already investigated claims going on in the blogosphere. Even the quotes taken from the README.txt file accompanying the leaked emails, which is the only part that most journalists will have read, are wildly out of context.

The following exchange is about an early version of Table 3-10 from Chapter 3, Working Group II Developing and Applying Scenarios in the Third Assessment Report. The table was a lot more complex than the final version, having stars denoting confidence and a wide range of extremes. After government review, the response was that the table was too complex and that the most important information to impart were the extremes known with relatively high confidence and their likely impacts. The final version shown to the right reflects those reviews. Read the rest of this entry »

Written by Roger Jones

December 1, 2011 at 9:41 am

Spinning uncertainty – IPCC SREX Redux

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I have an article on The Conversation Spinning uncertainty? The IPCC extreme weather report and the media. This works up some of the material in my previous post on the IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation Summary for Policymakers (IPCC SREX SPM). It gives, I reckon, a pretty good overview of the SPM and puts some of The Australian newspaper’s reporting of it under the spotlight. Go read.

One thing I didn’t mention was that there was a second story in The Australian tagged November 19 12:00 am that quoted Benny Peiser, directors of the Global Warming Policy Foundation, a UK climate change foggery set up by Lord Nigel Lawson. (It was reposted on the GWPF site). He said:

“there was not a strong empirical link between anthropogenic climate change and weather events”.

“It is unlikely there will be one for 20 to 30 years,” he said.

He said any suggestion that recent weather events could be directly linked to climate change went directly against the general scientific consensus.

Ummm, extreme temperatures? Right now?

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Written by Roger Jones

November 23, 2011 at 11:39 pm

IPCC SREX released

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The Summary for Policymakers (SPM) for the IPCC Special Report Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) was released late last night our time. The final plenary was held in Kampala Uganda, finishing on the 17th before the release yesterday. As usual, it is gone through line by line by IPCC country member representatives and the co-ordinating lead authors to craft a document that contains key policy messages while retaining true to the science in the report.

The SPM is complex and has already been given a number of interpretations in the press. The ABC news says extreme weather to worsen with climate change. The Australian focuses on the uncertainty Climate change effects unknown: IPCC report. A quick survey of Google news suggests that most outlets are focusing on extremes to worsen, or the qualified some extremes to worsen.

The Australian is different. Its header says:

GREAT uncertainty remains about how much of an impact climate change will have on future extreme weather events, the world’s leading climate scientists have found.

While there has been an increase in warm days and a decrease in cold nights, the likely impact on future weather events would not be evident for decades because of natural variability, the scientists say in a key review prepared for the UN’s Intergovernmental Panel on Climate Change.

This completely ignores the thrust of the report, which is to address the risks of extreme climate-related events and disasters and manage changing risk through adaptation. The great value of the report is not so much in its headline findings, which are complex but are in bringing the climate, adaptation and disaster communities together. These two communities had a hard time of it in the writing of the report bringing together different language, concepts, views of risk and methods of assessing vulnerability and adaptation. Read the rest of this entry »

Written by Roger Jones

November 19, 2011 at 7:59 pm

IPCC uncertainty management – new paper

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I’ve just had a paper, The latest iteration of IPCC uncertainty guidance—an author perspective, published online at Climatic Change. It claims that the new uncertainty management for the IPCC’s Fifth Assessment Report (pdf) is most suited to managing uncertainty in the physical sciences, and climate change as a complex, or ‘wicked system’ risk requires a more applied approach. The paper is open source so can be downloaded and read by anyone. Happy to get comments here. It’s part of a special issue in honour of the late Stephen Schneider, the chief uncertainty cop with the IPCC and climate science community, and founding editor of Climatic Change.

I can take credit for planting the seed of this issue in the minds of the new editors, Michael Oppenheimer and Gary Yohe. Abstract and special issue announcement over the fold. Links to open source papers so far posted and to the guidance documents, past and present, can also be found.

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Written by Roger Jones

September 25, 2011 at 7:46 am

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