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Monday, January 13, 2014

Extreme Heatwave hits Southeast Australia

This page may be updated further in coming days
Last week we saw record temperatures in a heatwave in Queensland and Western New South Wales with 34 maximum temperatures broken and mass deaths of flying foxes. The heat has been building over the last week in Western Australia and central Australia with an extreme heatwave across much of south east Australia forecast for this week.

Alasdair Hainsworth, Assistant Director for Weather Services at the Bureau of Meteorology said “What is unusual about this event, which the pilot heatwave forecast shows, is that when high maximum temperatures and above average minimum temperatures are sustained over a number of days, there is a build-up of ‘excess’ heat. Extreme heatwave conditions can be seen in southern NSW, Victoria and Tasmania."

Tess Parker from Monash University explains the dynamics of the heatwave at the Conversation: What’s cranking up the heat across south-eastern Australia?

The Australian Bureau of Meteorology has launched a new pilot heatwave forecast service this summer. "The heatwave service allows the Bureau to inform the community of the extremity of heatwave events, such as this one, for their planning and preparation. The new service is able to map the level of intensity of each heatwave event, indicating areas of ‘severe’ and ‘extreme’ heatwave at the upper end of the scale. The current event shows large areas of southern Australia will reach severe to extreme heatwave conditions." said Hainsworth.

Dr Sarah Perkins, a Research Associate for the ARC Centre of Excellence for Climate System Science at the University of New South Wales recently launched a new website called Scorcher, which shows the prevalence of heat waves across Australia, including historical data on temperature records for many locations. She commented on the current heatwave:

“Australia is no foreigner to heatwaves, particularly at this time of the year. They are generally the most intense since we are in what is generally the warmest part of the year. Southeastern Australia experiences some of the most extreme heat waves of the continent, particularly when local rainfall has been low and the right synoptic conditions, a slow-moving or stationary high-pressure system, occur. This brings warm air from the centre of the continent to the region affected for a prolonged period of time.

Although it is too early to tell how extreme the forming heatwave will be, this heatwave is yet another in a spade of extreme temperature events Australia has been experiencing for well over 12 months, with 2013 being the hottest year on record. Heatwaves have also recently been experienced in Queensland and western Australia. Also, the past two summers have also been "neutral" phases of the El Nino-Southern Oscillation phenomenon, when we expect average conditions. We usually expect to see hotter temperatures at higher frequencies during an El Nino phase, yet we've seen hot event after hot event when the modes of climate variability aren't conducive to this.

So while we do expect to see heat waves over Australia at this time of year, the context in which they are currently occurring is concerning. Australia's average temperature has warmed by 1°C due to human induced climate change, which is enough to increase the risk of the number and severity of extreme temperature events. While the current heatwave is just a single event, it is yet other link in the chain of a climatological shift towards more extreme temperature events, more often.”

Conditions similar to 2009

Conditions are looking similar to those experienced in 2009 in the lead up to the 2009 Black Saturday Bushfires. Professor David Karoly from Melbourne University describes those conditions in this February 16, 2009 post at the Realclimate blog: Bushfires and Extreme heat in South-east Australia. In that article Karoly says:

The extreme heat wave on 7 February came after another record-setting heat wave 10 days earlier, with Melbourne experiencing three days in a row with maximum temperatures higher than 43°C during 28-30 January, unprecedented in 154 years of Melbourne observations.

The heatwave is likely to increase fire weather for bushfires, warns Dr Jason Sharples, an ARC Research Fellow and Senior Lecturer in Applied Mathematics at the University Of New South Wales in this statement:

The heat wave that will effect a large portion of the country over the coming days has a number of important implications for bushfire risk. In fact, the forecast weather patterns are quite reminiscent of conditions before Black Saturday, with severe and expansive high temperatures across the southern part of the continent and the presence of low pressure cells on either side of the country in the tropics. In addition to temperatures above 40 degrees, the Bureau of Meteorology forecast is also indicating low atmospheric moisture, with relative humidity likely to fall below 20%. The combination of high temperature and low relative humidity means that the moisture content of vegetation will be very low. Hence, if a bushfire was to start, it would be expected to spread more rapidly than normal. Moreover, spot fires can be expected to be more numerous and to spread more rapidly. The community need to make sure their bushfire survival plans are in good order and are ready to be enacted. Careful monitoring of official emergency service websites is strongly advised.”

Heat in the west

On Saturday night Perth set a new overnight minimum temperature, according to this Sydney Morning Herald Report: "Saturday was Perth's hottest day since Boxing Day 2007, the city sweltered through the night. Weatherzone said the minimum of 29.7 degrees set at 3.12 am beat the warmest overnight low by 0.4 degrees in records going back 110 years." The temperature was 41 degrees by 9.39 am and reached 43.3 degrees with the arrival of sea breezes easing the rise. It was a new monthly maximum temperature record for January, exceeding the previous record of 42.9C set in 2013.

High temperatures overnight also changes Electricity usage demand:

Sadly, a bushfire in the Perth Hills on Sunday resulted in one death of a person defending their home, and 46 houses destroyed.

South east temperatures to soar

Inland regional towns will also feel the heat. The town of Wagga Wagga in the southwest NSW, reached 39 degrees on Sunday, and is expected to have a week of temperatures from 38-43 degrees to Saturday.

Victoria will also have very hot conditions in coming days. The Forecast for Shepparton shows 5 days of 40C+ temperatures from Mon, and 44C for Thursday & Friday. This is greater than 14C above the long-term January average.

The temperature in Canberra hit 37 degrees on Sunday afternoon, but a cooler day at 33 degrees on Monday before expected highs of 39 degrees on Wednesday and Thursday.

So far Melbourne has had a relatively mild summer but this week the Bureau of Meteorology has forecast Maximum temperatures all week at 35 degrees and above. Three days are forecast to reach 40 degrees and above. The average number of 40C days for Melbourne is just 1.5 per year.

Is this summer going to be a repeat of the Extreme Heatwave for Australia January 2013 and the 2013 sizzling autumn and angry summer?

Heatwaves are a public health threat

Associate Professor Adrian Barnett, a Principal Research Fellow in the Faculty of Health at Queensland University of Technology, highlighted that heatwaves pose a major public health threat:

“Extreme heat is very bad for our health. Everyone’s cardiovascular system has to work harder when it’s hot, and for some people this extra strain can cause a myocardial infarction or stroke. People with pre-existing cardiovascular disease are at much greater risk, as are the elderly, especially those with dementia. People living in high density inner city areas are also at greater risk because for them the temperature is even hotter because of the urban heat island.

Staying in air conditioning is the best way to reduce your risk, and people should also keep hydrated, avoid alcohol and check on their neighbours. Two things that can make a heat wave far worse are power blackouts and bushfires. Blackouts shut down air conditioners, which are the best way to reduce risk during a heat wave. Bushfires add air pollution to the mix which further challenges peoples’ cardiovascular systems. If lots of people become ill due to the heat then ambulances and hospitals can become extremely busy and the health system struggles to cope.”

The heatwave that caused Victoria's Black Saturday bushfires in 2009 killed 173 people directly, but also proved fatal to those at risk of heat fatigue: children and the elderly. A report - January 2009 Heatwave in Victoria: an Assessment of Health Impacts (PDF) - found that:

There were 374 excess deaths over what would be expected: a 62% increase in total all-cause mortality. The total number of deaths was 980, compared to a mean of 606 for the previous 5 years. The greatest number of deaths occurred in those 75 years or older, representing a 64% increase;

Associate Professor Margaret Loughnan, a Research Fellow at Monash Weather and Climate, Monash University, said that "Extreme heat IS a risk to people’s health. Older people, babies and young children and people with pre-existing illnesses are at high risk of heat related illness or death during heatwaves."

Loughnan advised several Key health tips for a heatwave :

  • avoid exposure - stay out of the sun and close blinds and curtains to shade rooms
  • avoid strenuous activity especially outdoors
  • keep drinking – by the time you feel thirsty your body is already dehydrating so drink often to avoid thirst
  • use air-conditioning or fans and wet the skin with moist towels to stay cool
  • wear loose, lightweight clothing and have a cool shower or tepid bath for babies and children
  • Check on elderly family, friends and neighbours especially when heat persists for several days.
  • Information about heat related illness and coping with the heat is available at:

Dr Liz Hanna warned that with a warming planet extreme heatwaves are no longer rare events and it is important that Australians learnt to adapt to manage these events. "Yes we have always had hot summers, but the broken temperature records show us that these are now more common, hotter, and they are lasting longer. We cannot assume we will be OK. It is the complacency that can kill. Most at risk are of course the very young, the elderly, and those with chronic health problems, such as cardiac or lung disease. People with mental health problems, and the socially isolated are also very vulnerable to heat."

Dr Hanna is a Director of an NHMRC Project: Working in the Heat - health risks and adaptation needs. She is also a Fellow of the National Centre for Epidemiology & Population Health at the Australian National University, and President of the Climate and Health Alliance. She advises that heat extremes pose a serious health risk, and must be respected by taking precautions to avoid succumbing to heat stress:

"Heat effects increase in a cascade of health symptoms of increasing severity. Everyone should know the early signs of heat stress, so they can provide assistance. Signs include headache, nausea, dizziness, weakness, irritability, thirst, and heavy sweating. The skin can be cold and clammy. Loss of salt from sweating can produce cramping. Anyone showing these symptoms should be taken to a cool place, rested and given cold drinks (no alcohol). Hot dry skin is a dangerous sign. Confusion can lead to loss of consciousness, seizures and ultimately death, so these are a medical emergency, and must be treated in a hospital.

The temperatures inside a car can exceed 70oC, so children, the frail or pets must never be left in a car. Heat can and does kill, so it must be respected as a significant health threat, to everyone! The key health messages are to prevent heat stress by postponing exercise, doing lighter work, staying in the shade or cool environments, dressing appropriately, and remembering to drink, drink, drink. The second message is to be familiar with the danger signs, and look out for each other at work, at home, and in public places. All Australians must heed the summer health threat. Sporting event organisers and workplace managers have a duty of care to provide safe environments and protect human health against this known health risk.

The most powerful protection of human health from the ravages of heat is to prevent the world from warming. Governments must recognize their duty of care to current and future generations by turbo boosting the current lacklustre attempts to prevent the greenhouse disaster. Without rapid decarbonising our economy, a global health crisis will inevitably follow, and global conflict will exacerbate as millions seek to secure diminishing food and water supplies, and access to habitable climates zones.”

While heatwave temperatures are mainly measured by daytime maximum temperatures, night time minimum temperatures are important for allowing biological systems to recharge and sleep. When minimum temperatures stay high, it impacts human health by disrupting sleep and not allowing core body heat to cool overnight. That point where temperature affects sleep is about 23 degrees Celsius.



Urban populations at higher risk due to Urban Heat Island effect

Populations in urban environments like Sydney, Adelaide, Melbourne and Hobart are also at particular risk as extreme heatwaves are amplified by the Urban Heat Island (UHI) effect. A study published in July 2013 showed that Urbanization amplifies global warming temperatures for Sydney.

A study (Cunrui Huang et al (2012)) on The impact of temperature on 'years of life lost' in Brisbane, Australia, projected the potential impact climate change will have in terms of life years for people that live in Brisbane. It found that temperature-related deaths currently account for 6,572 years of life lost per year in Brisbane, almost double the rate for breast cancer.

Study co-author Associate Professor Adrian Barnett of Queensland University of Technology's Institute of Health and Biomedical Innovation (IHBI), said in a media release things would only get worse as Climate Change continued. "A 2°C increase in temperature in Brisbane between now and 2050 would result in an extra 381 years of life lost per year in Brisbane," he said. "A 4°C increase in temperature would result in an extra 3,242 years of life lost per year in Brisbane," he warned.

Further afield, a New York study into heat related deaths for Manhattan published May 2013 found that by the 2020s there will be a mean increase of about 20 percent in deaths due to heat, set against a mean decrease of about 12 percent in deaths due to cold, with a net result of a 5 or 6 percent increase in overall temperature-related deaths. The study concluded that heat related mortality is expected to rise steeply in projections for the 2050s and 2080s, despite alternate emissions scenarios.

Animals also suffer and need assistance


Pets and animals, including wildlife are also under stree during extreme heatwave conditions. This was demonstrated by the thousands of deaths of flying foxes last week in Queensland.

Roger Paskin, Chief Veterinary Officer, Primary Industries and Regions in South Australia says “It sounds obvious but it is worth repeating: animals of all kinds need shade, wherever possible, to protect them from searing sun and wind. Also, they need good supplies of cool water; animals can drink up to double their normal intake during hot weather. Keep drinking troughs large and clean, especially when moving stock into a fresh paddock as evaporation may make trough water become saline and undrinkable.”

Even if you live in the city, shade and water is often used by birdlife to survive the hot temperatures. Filling birdbaths with water can be a lifesaver for suburban birds.


Federal Government in climate denial winding back climate policies


While Australia swelters through this heatwave, the Australian Government Lead by Prime Minister Tony Abbott is proceeding with it's plans to dismantle climate and energy policies by rolling back the carbon price and reducing support for transition to renewable energy. Giles Parkinson writes Abbott won’t let facts derail his anti-renewables campaign. Alexander White in the Guardian writes that the Australian environment minister is totally, shamefully negligent with "direct action" policy.

This is despite the Bureau of Meteorology confirming that 2013 was the hottest year on record for Australia. The Climate Council's Professor Will Steffen released a new report saying that the 2013 temperatures were off the charts. Even more concerning, climate scientists Professor David Karoly and Sophie Lewis released preliminary results of a Fractional attribution study showing that in 13,000 model years not one year exceeded the previous hottest year in 2013 using just natural forcings. Whereas the models show that using human and natural forcing record temperatures are likely to occurr approximately once in every 10 years between 2006 and 2020.

Last year Australia endured it's hottest September on record and three times hottest 12 month to month period on record. We had an unusually early start to the bushfire season in September around Sydney. There were major fires surrounding Sydney and the Blue Mountains in October, while Prime Minister Tony Abbott demonstrated his denial of the link between record temperatures and bushfires.

Sources:

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