Archive for the ‘Climate observations’ Category
During the last weekend in July, Perth experienced an unusually high number of deaths, putting pressure on the state’s mortuaries. All facilities are full, according to the ABC.
Curiosity piqued, I checked Perth’s weather data for unseasonal cold. Sure enough, during June and July, Perth and the rest of south west WA had experienced cold conditions, not seen in Perth for 13 years and longer elsewhere. This linked article was published in mid July. In the last three weeks of July, daily temperatures were below 10 degrees on 3, 4 and 3 days, respectively preceding the last weekend of July.
Was it the the poor, the aged and the infirm filling the mortuaries, after repeated, unseasonal cold snaps? Has an overall warmer climate not insulated people from such events? The average temperature at Perth Airport is 13°C and for July was 11°C; perhaps there are some bad respiratory diseases around making things worse.
Cold remains dangerous for the vulnerable in southern winters. At this range of temperature, contrasts in temperature are the largest risk to vulnerable people, rather than absolute temperatures themselves.
After me getting an op-ed in The Age representing real climate science and policy, it’s time for some asshattery, c/- both the Melbourne Age and the Sydney Morning Herald. The Fairfax press has decided to redress the balance of knowledge with some agnotogeny* from Dr David Evans. From his tagline:
Dr David M. W. Evans is a mathematician and engineer who consulted full-time for the Australian Greenhouse Office (now the Department of Climate Change) from 1999 to 2005. He says he changed from being a warmist to a sceptic after ”evidence supporting the idea that CO2 emissions were the main cause of global warming reversed itself from 1998 to 2006”.
Oh purleeze. Read the rest of this entry »
Rapid warming in SE Australia challenges plans to adapt gradually
Step changes in warming of a few tenths to 1°C can produce rapid changes in risks such as extreme heat and fire danger. Yet, adaptation-planning that follows the dominant model of smooth climate change makes gradual adjustments to keep up with small changes in extremes. In these circumstances, a rapid change can catch sensitive systems out. Poorly planned responses may also lead to maladaptation.
Studies of prehistoric climate change in Victoria’s western lakes imply that future changes might not be smooth. Dacre Smith's painting of Lake Gnotuk, from Views of Victoria in the steps of von Guerard.
Last Friday the global climate conspiracy erected another plank dressing up the façade that is record of warming record in Australia. At an extra-ordinary nerdfest held the Victorian State Library, the cruel manipulations of temperature records by the Bureau of Meteorology were described. ACORN-SAT, I mean, really! Lies dressed up as statistics were outlined to an audience who hung on every word. The conspirators have done such a good job that the Australian record so closely resembles the tricked up records from Hadley-CRU, the Goddard Centre for Space Studies and NASA, that they all have to be made up. There’s no way that independent analyses of measurements of something we can’t see – air – can be so accurate.
Well, that’s the objections of the denialati out of the way.
The BoM did release The Australian Climate Observations Reference Network – Surface Air Temperature (ACORN-SAT) data on Friday and it looks excellent. Today I’m downloading some of the data for a project I’m involved in, so it’s good to have. The data were also used in the recent State of the Climate 2012 released by the Bureau and CSIRO.
Part of the impetus to get this done was a barely coherent set of assertions on how Australia’s climate records were being massaged by the Bureau. These assertions were formally submitted (pdf) as a request to audit climate records to the Attorney-General in February 2010. Co-signees were Senator Cory Bernardi, Joanne Nova (an alias), Andrew Barnham, Anthony Cox, James Doogue, Chris Gillham, Ken Stewart and Dr David Stockwell. They also alleged that BoM and CSIRO advice on climate change was misleading. This follows up similar fishing expeditions in New Zealand and the US yielding similar results. Not only were the records validated, quality control methods and subsequent adjustments improved those data giving us even more confidence that the record of warming they contain is unimpeachable.
Improved methods, external international review and a more comprehensive coverage have led to the Bureau to claim they have the some of the best quality records of temperature of any country. I think they’re right.
The climate shifts paper on non-linear anthropogenic climate change in SE Australia with earlier descriptions here and here, has been published in the Journal of Geophysical Research. We had plans to make it open access but must not have paid the invoice yet, so it’s behind a paywall here (pdf). If you can’t get access, get in touch with me via comment below or email (firstname.lastname at vu.edu.au) and I’ll send a reprint.
Following is an edit of the draft press release that should go out in the next week or so. The press release implies that this pretty much goes on everywhere – not just SE Australia. That’s what I believe from further work currently underway – the ocean runs the climate system and the atmosphere doesn’t warm quite the way people assume it does. The energy from greenhouse warming goes into the ocean first, then is re-emitted periodically into the atmosphere. The atmosphere doesn’t warm in situ (or not yet to any significant degree). It may later under increased radiative forcing, but at the moment the ocean is pretty much running the show. This pattern of non-linear change fits in with palaeoclimatic evidence from the region that I’ll get round to describing some time.
This posts looks at how climate shifts affect extremes using the example of heat extremes in SE Australia. We had another burst of hot weather this week, which led to rolling power blackouts in South Australia. These are becoming more common, as our electricity bills rise to pay for network infrastructure. In every year but one since 1997, the Laverton, Victoria climate record has registered at least 1 day above 40°C. For those of you interested in how the science of detecting and projecting extremes is carried out, there is a comprehensive background on methods. For those who are just interested in results, page down to the results section. Read the rest of this entry »
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 »
The Sunday Age – OurSay readers questions on climate change are down to the last two:
- ”THE claim ‘the science is settled’ is plainly false due to the many problems with the AGW [anthropogenic global warming] hypothesis (e.g. global temperatures have not risen since 1998 despite rising CO2 levels; alarmism is based on flawed models that do not reflect empirical measurements.)”
- ”Why is the Australian public asked to swallow the ‘carbon dioxide is a dangerous climate-changing pollution’ crap when science shows no observed relationship between global climate and atmospheric carbon dioxide? There is no physical evidence showing a relationship between temperature and CO2, only computer models which give different answers according to whatever assumption data you put in. But there is a very close relationship between temperature and solar activity … Why, when thousands of respected scientists signed a petition saying they don’t agree there is a problem, are we being forced to give up billions in tax dollars to waste on trying to stop carbon dioxide emissions?”
Sea level rise Part I covered the stoush resulting from a paper on long-term tide gauge records for Australasia. The author was Phil Watson of the NSW Department of Environment, Climate Change and Water and the paper was published in the Journal of Coastal Research in March. Tamino has pointed out the limitations of the statistical methods used, showing that the conclusion of decelerating sea level cannot be sustained. Tamino removed the annual cycle then used 20-year and lowess smoothing to show that the opposite conclusion – recent sea level rise is accelerating – is probably true for the Australasian region. A conclusion I strongly support.
It’s generally accepted that long-term climate records are analysed using trend analysis; either as a linear or non-linear trend, usually quadratic. The use of a particular statistical method assumes a specific model of how a system behaves. That model can be made explicit but if not, there is still an assumed model being used. Sometimes the assumption won’t be declared because it’s a widely accepted paradigm.
So what is the model sitting behind trend analysis – measured as either a straight line or a curve – and what paradigm of change process does it support? By analysing single tide gauge records, I am asking “How does sea level respond to externally-driven warming at a given location?” Read the rest of this entry »
A stoush on Australiasian sea level rise has erupted in the press and the blogosphere since the publication on July 22 of a story in The Australian covering a paper analysing long tide gauge records in Australasia. The details are covered comprehensively by Deltoid. The paper, by Phil Watson of the NSW Department of Environment, Climate Change and Water was published in the Journal of Coastal Research in March. It concluded that:
The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000. Short period trends of acceleration in mean sea level after 1990 are evident at each site, although these are not abnormal or higher than other short-term rates measured throughout the historical record.
The Australian misprepresented this conclusion by calling in question 21st century projections of sea level rise (SLR). There is a very simple reason as to why this is not the case. The projections are about current and future ocean budgets, whereas the tide gauge records are more about process. Sea level budgets are known well enough to provide very high confidence that SLR will accelerate throughout the 21st century. The process of sea level rise at a site as measured by tide gauges is complex. Watson’s conclusions as emphasised by himself, his employers and real experts do not call into question the basic science about future SLR budgets.
However, as to the process of SLR I think the statistics currently being used don’t tell the full story. In part I, I summarise the story to date and in Part II, I will show an alternative method for analysing long-term tide gauge records. Read the rest of this entry »