Understanding Climate Risk

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Archive for the ‘Floods’ Category

Two summary climate reports for Oz

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Yesterday the Bureau of Meteorology and CSIRO released their State of the Climate 2012 report and today the Climate Commission released The science behind southeast Australia’s wet, cool summer. Both documents outline the latest changes with clear explanations and useful diagrams.

State of the Climate 2012 showed a general trend toward increased spring and summer monsoonal rainfall across Australia’s north, and a decline in late autumn and winter rainfall across southern Australia.

Sea-levels had risen around Australia at rates equal to or greater than the global average, and sea-surface temperatures in the region had increased faster than the global average.

State of the Climate 2012 documents the annual growth in global fossil-fuel CO2 emissions and other greenhouse gases. The CO2 concentration of the atmosphere had risen to around 390 parts per million in 2011, a level unprecedented in the past 800,000 years. During the past decade it has risen at more than 3% per year, which is projected to cause significant further global warming.

The Climate Commission Report was written by Professors Will Steffen, Matt England and David Karoly:

Most parts of Australia have experienced exceptionally heavy rains over the past two years, filling many dams around the country and breaking the drought of 1997–2009. There has been much confusion in the media about what this means for climate change. This report seeks to set the record straight.

The main point for me, which I fully endorse:

Climate change cannot be ruled out as a factor in recent heavy rainfall events. The Sea Surface Temperatures (SSTs) around northern Australia during the spring and early summer of 2010–2011 were the highest on record. This has very likely contributed to the exceptionally heavy rainfall over much of Australia in the last two years. La Niña events bring high SSTs to the seas around northern Australia, but warming over the past century has also contributed to the recent record high SSTs.

Written by Roger Jones

March 15, 2012 at 6:10 pm

Northern Victorian Flood Review Part III

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This is the third post covering the January 2011 floods in northern Victoria. Part I described how the floods unfolded and Part II described the hydrology of the Loddon catchment and how its history has affected flood behaviour. This final post covers the climatic influences on the floods. The floods themselves are discussed here, and affects on the family farm in Kerang are shown here.

Northern Victoria’s rainfall is influenced by the El Niño–Southern Oscillation (ENSO; spring–summer), Indian Ocean Dipole (IOD; winter–spring) and Southern Annular Mode (SAM; winter). Correlations of northern Victorian rainfall with simple indices are -0.51 for SOI May–Jan, ‑0.48 and -0.45 for two IOD indices May–Jan, and -0.25 for SAM for winter rainfall.Recent research has linked exceptionally wet conditions in south-eastern Australia with the combination of La Niña and a negative Indian Ocean Dipole (-IOD) (Ummenhofer et al., 2009; Ummenhofer et al., 2011).

The -IOD is associated with exceptionally warm waters off north-western Australia resulting in ‘north-west’ cloud bands that bring flooding rains into northern Victoria. The recent extended drought in Victoria has been characterised by an absence of these weather patterns. While central and north-western Australia have become wetter, this rainfall source has been conspicuously absent from south-eastern Australia.

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Written by Roger Jones

June 3, 2011 at 3:37 pm

Northern Victorian Flood Review Part II

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This post examines the hydrological influences on past and present flooding leading to the January 2011 floods in northern Victoria. The floods themselves are discussed n Part I here, and affects on the family farm in Kerang are shown here. Part III on climatic influences is here.

Local data used are daily flows at Laanecoorie Reservoir on the mid Loddon River, and daily rainfall from the Newstead and Cairn Curran rain gauges upstream. Hydrological issues concern long-term catchment change and flow data. These affect the assessment of historical floods on the Loddon River.

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Written by Roger Jones

May 22, 2011 at 11:17 am

Northern Victorian Flood Review I

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This post reviews some of the events that led to the northern Victorian floods of January 2011. Part II looks at the hydrological influences and Part III on the climatic influences on the floods. Recommendations for the flood review are made in Part III.

There are two flood enquiries happening in Australia at the moment. The one in Queensland is understandably much higher profile because of the loss of life and damage caused. It has the powers of a Royal Commission, so can subpoena, call witnesses and cross examine.

Victoria’s enquiry is a review. Former Police Chief Neil Comrie has been appointed to examine matters extending from flood prediction and warning all the way through to access to emergency funding and government services. Public meetings are being held in affected areas and written submissions are being taken until May 27.

The biggest difference is the Review is more reflective and will address the information delivered, whereas the Commission is investigative and is charged to assess contributing cause to the disaster and its management. It can interrogate.

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Written by Roger Jones

May 13, 2011 at 2:37 pm

The big wet Part 1

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In this long post I describe how climate change and variability have contributed to the big wet of the past year and outline a role for climate change that challenges the orthodox model of understanding how climate changes through trend analysis.

Last year was the second wettest year recorded in Australia since 1900. Deadly floods occurred in Queensland and a series of increasingly severe floods affected Victoria and New South Wales during spring and summer. There is no doubt the origin of the wet year was due to climate variability. The strongest La Niña on record with an SOI of 21.5 from Sep–Dec was the origin of the wet conditions.

  • Total Sep–Jan rainfall in eastern Australia was 602 mm second only to 1972–3, just beating 1974–5. Sep–Dec rainfall was 425 mm, the wettest on record.
  • The El Niño-Southern Oscillation (ENSO) Index averaged 21.5 over the Sep–Feb period; the strongest on record, producing very strong La Niña conditions.
  • The Indian Ocean Dipole (IOD) was negative between Aug–Oct 2010. A negative IOD is characterised by warmer than usual waters near Indonesia. The combination of a negative IOD and La Niña is rare and results in wetter than usual conditions across much of Australia (see http://www.bom.gov.au/climate/IOD/negative/).
  • Victoria recorded its wettest January at 119 mm and Sep–Jan at 532 mm.
  • Pan evaporation and diurnal temperature range over eastern Australia in 2010 were the lowest on record.

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Written by Roger Jones

March 20, 2011 at 4:32 pm

After the floods – reactive vs planned responses

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Prime Minister Julia Gillard has proposed a flood levy and spending cuts and deferrals to help pay the bill for the recent Queensland floods. Referring to it as “a natural disaster of unprecedented proportions”, she is now on the road to persuade others in government, industry and the community to back her plan.

It’s worth having a closer look at, with details here and here .

It comprises:

  • $2.8 billion in spending cuts, including removing industry assistance and cutting back other green programs by abolishing the Green Car Innovation Fund and the Cleaner Car Rebate Scheme and making other cuts.
  • $1 billion in delaying some infrastructure projects– which will free up funds and skilled workers at a time of skilled labour shortages around the country.
  • $1.8 billion through a progressive levy on people earning over $50,000. This will only apply to income above the $50,000 threshold. Anyone directly affected by the floods will not have to pay the levy at all.

I’m not arguing against the levy or the scheme in total, but feel that the current approach is reactive and not strategic. My position is that we are facing a long-term issue rather than just recovering from a short-term disaster.

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Written by Roger Jones

January 28, 2011 at 12:32 pm

Floods-the amusing side

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When the farm went under water on Tuesday and Wednesday, the whole town of Kerang was cut off. Everyone had to find something to enetertain themselves, so they drove up Ninth Street to have a look-see. What is a dead-end street turned into Bourke St as everyone drove up to have a look, stopped, then turned around and drove back into town. So Mum put this sign out front:

In no time, we had this response:

Written by Roger Jones

January 23, 2011 at 10:57 pm

Posted in Floods, Humour

Kerang Floods

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I returned to Australia from Japan Sunday 16 and was on the train the next morning and topping up levee banks in the afternoon. We lost the fight against the floods late Tuesday and another peak Wednesday showed we had no hope of holding the flood back. The water is very beautiful. Blue skies, frogs, birds, but it’s a tad inconvenient. This is the front drive – on Wednesday. 

Front Drive, Kerang Model Farm

 There is an official Bureau of Met weather station – this is what it looked like on Wednesday – the new fangled extra large-sized evaporation pan (approximately 500 hectares in size).

Kerang Model Farm met station Jan 19, 2011

From the bird’s eye view, this is where we are (the small area of dry land inside the white boundary):

Kerang Model Farm Aerial photo Jan 19 2011

The town of Kerang is just to the north of the farm and the Loddon River is to the west – photo right. The farmhouse is about a century old and has never been flooded because it’s on a small rise about 1-2 m higher than the surrounding floodplain.

Written by Roger Jones

January 23, 2011 at 10:46 pm

Posted in Floods

Open letter to the Victorian Governor re comments on floods and climate change

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The Governor of Victoria Professor David De Kretser recently commented on the floods and climate change on Radio 3AW, making the following comment: ”I’m sorry, I’m one of these believers in climate change, I’m afraid, and … I don’t think it’s going to go away.

”There’s too many of these events, not only in Australia but throughout the whole world that are happening now … Everyone says this week [is a] one in 100, one in 200 years [event] but they are happening pretty much more frequently now.”

These comments were reported in The Age and the Herald Sun and more widely (98 news articles on Google on Jan 23). The Premier Ted Baillieu said it was too early to make a comment on climate change, then went to say that he had been told on Jan 18 by Melbourne Water that Victorians should expect 30 per cent more rainfall in the next 10 years – I’m trying to track down the source of this statement because it’s difficult to countenance. The Governor’s statement was flatly rejected by climate expert Andrew Bolt (I refuse to link) and today by commentator  Eddie McGuire, who somehow thinks climate change is a distraction.  Not if you don’t adapt to a changing climate because you’re busy recreating past, Eddie.

Following is an open letter I wrote to the Governor today and forwarded to The Age.

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Written by Roger Jones

January 23, 2011 at 10:25 pm

Posted in Climate change, Floods, Risk