08/06/2018

Is Australia’s Current Drought Caused By Climate Change? It’s Complicated

The Conversation - Andrew King | Anna Ukkola | Ben Henley

IVAN MCDONNELL/AAP
Much of southern Australia is experiencing severe drought after a very dry and warm autumn across the southern half of the continent. Australia is no stranger to drought, but this recent dry spell, and Prime Minister Malcolm Turnbull’s visit to drought-stricken parts of the country, has prompted discussion of the role of climate change in this event.
Turnbull said that farmers need to “build resilience” as rainfall “appears to be getting more variable”. This prompted former Nationals leader John Anderson to warn against “politicising” the drought by invoking climate change. This in turn was followed by speculation from numberous commentators about the links between climate change and drought.
So are droughts getting worse, and can they be attributed to climate change? Drought is a complex beast and can be measured in a variety of ways. Some aspects of drought are linked with climate change; others are not.

Recent warm and dry conditions have resulted in drought over parts of southern Australia. Bureau of Meteorology
 How do we measure drought?
In Australia, the Bureau of Meteorology uses rainfall deficiencies to identify regions that are under drought conditions.
Droughts are also exacerbated by low humidity, higher wind speeds, warmer temperatures, and greater amounts of sunshine. All of these factors increase water loss from soils and plants. This means that other metrics are often used to describe drought which go beyond rainfall deficiencies alone. These include the Palmer Drought Severity Index and the Standardised Precipitation Evaporation Index , for example.
This means that there are hundreds of metrics which together can provide a more detailed representation of a drought. But this also means that droughts are less well understood and described than simpler phenomena such as temperature and rainfall.
Hydrological drought, often defined by a period of low streamflow, is a response to numerous upstream processes that are unique to each river system. Hydrologists and water planners therefore often focus on directly observing and modelling runoff from water catchments.
The point here is that droughts can be multidimensional, affecting agriculture and water supplies on a wide range of spatial and temporal scales. A seasonal-scale drought that reduces soil moisture on a farm, and a decade-long drought that depletes reservoirs and groundwater supplies, can both be devastating, but in very different ways.

So is climate change affecting Australian droughts?
As we have so many ways of looking at droughts, this is a more complex question than it might first sound. Climate change may affect these drought metrics and types of drought differently, so it is hard to make general statements about the links between human-induced climate change and drought.
We know that over southern Australia, and in particular the southwest, there has been a rapid decline in winter rainfall, and that this has been linked to climate change. In the southeast there has also been a decline but the trend is harder to distinguish from the year-to-year variability.

Winter rainfall in Southwestern Australia has been in decline since the 1960s. Bureau of Meteorology
For recent short-term droughts in southern Australia, analyses have found an increased likelihood of rainfall deficits related to human-caused climate change. Also, it has been suggested that the character of droughts is changing as a result of the human-induced warming trend.
There is some evidence to suggest that widespread and prolonged droughts, like the Millennium Drought, are worse than other droughts in recent centuries, and may have been exacerbated by climate change. But the role of climate change in extended drought periods is difficult to discern from background climate variability. This is particularly true in Australia, which has a much more variable climate than many other parts of the world.

What does the future hold?
Future projections of drought are also difficult to constrain, as they vary across Australia and depend on the measure of drought being used. Climate models project a continuing decline in rainfall over southern Australia over the next century. Dry conditions like those seen in southeast Australia in 2006, for example, are projected to become more frequent under even low global warming targets associated with the Paris Agreement. Rainfall projections for other parts of the continent are more uncertain.
Rainfall is projected to become more extreme, with more intense rain events and fewer light rain days. This would potentially influence what future droughts look like, and how and where water moves through the land.
River flows are also projected to decline in parts of the country, with consequences for water supply to cities, ecosystems and agriculture. In the southwest, declining rainfall has led to drastic reductions in river flows since the 1970s. This trend is expected to continue. Elsewhere, changes are more uncertain but studies have suggested that the southeast could also experience declining river flows in the coming decades.
Part of the challenge of projecting future change is related to how temperature and precipitation vary together. The relationship is a double-edged sword. Increased greenhouse gas emissions mean an increased probability that low-precipitation years are also warm, suggesting that under climate change droughts may be hotter in some parts of the world. But dry conditions also often result in warmer local temperatures, increasing water loss from soils and plants.

 Droughts are tricky
Compared with other extreme weather types, it is hard to make useful statements about how climate change is altering droughts and their impacts. Protracted droughts are also rarer than many short-term natural hazards such as heatwaves. We need much longer records to reliably understand how they are changing, but these are not always available.

Compared to heatwaves and cold spells it is harder to assess the role of climate change in droughts. National Academy of Science
There is some evidence to suggest that climate change is exacerbating drought conditions in parts of Australia, especially in the southwest and southeast. Much more work is needed to understand the intricacies of the effects of climate change on different aspects and types of drought.
With the uncertainties of a rapidly changing climate we need to bolster our adaptation plans so we are ready for the next big dry.

Links
at No comments:

Move To Renewables A 'Good Thing', Nationals' David Littleproud Says

The Guardian -

David Littleproud: ‘The climate is going to change and we’ve got to move with it.’ Photograph: Lukas Coch/AAP
The agriculture minister, David Littleproud, says the climate is changing and the transition in the energy market – with renewables displacing traditional power generation sources – is “exciting, not only for the environment but for the hip pocket”.
In an interview with Guardian Australia, the Queensland National said the climate had been changing “since we first tilled the soil in Australia” and he does not care whether the change is due to human activity or not.
While some colleagues in the National party have long queried whether humans are contributing to global warming, and have been openly hostile to the advance of renewable energy, Littleproud said: “I’m not losing any sleep on that, whether you want to prove it is manmade or not – I want to be pragmatic.
“The climate has been changing since we first tilled the soil in Australia and the reality is farmers have been adapting to it,” the agriculture minister said. “Farmers are always at the cutting edge of science and technology, and they’ve been adapting since we first tilled the soil here.
“I believe the climate is changing. Whether it is manmade or not, I don’t really care. The reality is we are seeing disruption, particularly with renewables, and we are going to see cleaner air. I try not to live in cities, you do feel the effects ... so it’s a good thing that renewables are coming on.
“In fact, in my own electorate [of Maranoa in south-west Queensland] I’ve got all of the above. I’m about to have one of the largest solar farms in the southern hemisphere, one of the biggest wind farms in the southern hemisphere. I’ve got geothermal and I’ve got four coal-fired power stations. Two of those are super critical.
“The disruption that’s happening with the technology, moving towards renewable energy, particularly in storage for base load, is exciting. I think it is a good thing.”
While some government colleagues have championed prolonging the life of coal-fired power plants, Littleproud said economics rather than a culture war would ultimately determine Australia’s future energy mix. “Economics will win out in the end and if base load power can be stored in particular, that’s an exciting thing for the environment and everyone’s hip pocket.”
Littleproud has been on the road for much of the week with the prime minister, Malcolm Turnbull, visiting drought-affected regions of New South Wales and Queensland.
The south-east of Australia this year has experienced record high temperatures during an unseasonably dry and hot autumn, prompting fire bans and warnings from authorities.
David Littleproud campaigning with prime minister Malcolm Turnbull in Queensland this week. Photograph: Lisa Alexander/AAP
In its latest winter outlook, the Bureau of Meteorology is forecasting warmer and drier-than-average conditions across large parts of the country. It suggests winter rainfall is likely to be below average for NSW, South Australia, northern Victoria and western parts of Western Australia.
Turnbull this week said there was “no doubt that our climate is getting warmer”. He said the farming community needed to concentrate on becoming more resilient and focus on adaptation to a climate that was getting warmer and drier.
Littleproud said there was a place for both mitigation strategies to try and reduce the most damaging impacts of climate change, and also for adaptation.
“No matter whether you mitigate or adapt, the climate is going to change and we’ve got to move with it,” he said. “You have to use the best science available at the time – you mitigate as best you can ... listen to the scientific evidence, because this should be predicated on science not emotion.
“If there are mitigation efforts to lessen the impact, then we should explore those, but we have to continue to adapt as we have since we first inhabited Australia.”
He said he was currently working with state counterparts in the agriculture portfolio to develop “a national strategy around climate change adaptation”, which would include better collaboration across state borders, more research and development, including developing more drought-resistant grains and fibres, and looking at the genetics of livestock, and “understanding the weather better”.
Asked whether some Australian farmers were hanging on in areas made unviable for agricultural production because of the impact of climate change, Littleproud said: “I think ultimately the market and economics determine that.
“I honestly believe, having been a bank manager that sat around farmers’ kitchen tables, the greatest custodians of the land are farmers because their profit and loss is intrinsically tied to the health of their land. They don’t make a quid unless their environment and their farming is at its best.”
He said farmers in drier areas were deploying active strategies, like reducing their stocking densities, and some farmers he had met in regional Queensland this week were also engaged with traditional owners about land management.
“They’ve learned how to manage that land, in some ways learning from how Indigenous Australians manage the land and techniques they’ve used,” he said.
Asked whether he accepted that agriculture and transport industries had to reduce their emissions to ensure Australia met its commitments under the Paris agreement, Littleproud said emissions reduction had to be “responsible”.
I think we are already reducing emissions
David Littleproud
The latest official emissions data shows pollution increased by 1.5% in the year to December 2017. Australia’s emissions levels are now higher than they were in 2012 and have climbed by 3.6% since the carbon price was repealed in 2014.
Emissions are increasing in most sectors of the economy – in waste, agriculture and transport. Only one sector of the economy has recorded a decrease – the electricity sector – because ageing coal-fired power plants have exited the system, and new renewables projects are coming on stream.
“We’ve still got to be able to reduce the bills,” Littleproud said. “We’ve got to make sure the transition is done with people being able to turn their heaters on, and farmers turning their pumps on.
“I think we are already reducing emissions. We’ve made a commitment under the Paris agreement and we are moving towards that in a sensible and methodical way.
“As disruption happens in the technology space, [emissions reduction] will increase. In my own electorate, people are self-sustaining through solar. The reality is that type of disruption is happening and that is an exciting thing not only for the environment, but for the hip pocket.”

Links
at No comments:

Climate Change-Related Disaster Relief Is Increasing Demand On Defence Department, Senate Hears

ABC News - Ben Deacon

Private Daniel Bond and a Vanuatu resident work together on building repairs after Cyclone Pam. (Supplied: Tom Gibson/ABIS )
The Department of Defence has spelled out clearly to a Senate enquiry that climate change is increasing demand and will create "concurrency pressures" for the Australian Defence Force as a rise in disaster relief operations continues.
"The ADF is … built around the most demanding and most complex of its roles, the warfighting role," the Defence Department told a Senate enquiry into climate change and security last month.
"Due to the nature of its capabilities it is able to make a contribution to Humanitarian Assistance and Disaster Relief (HADR), though the force is not structured around this task."
At the moment, while Australia has no large-scale war commitments, Defence says its can handle the workload.
"However, the forecast level of commitment may create concurrency pressures for Defence from as early as the middle of the next decade, or earlier if climate change-related impacts on security threats accelerate."
A graph supplied to the Senate shows the number of ADF disaster missions increasing alongside the number of disasters across the Asia-Pacific. (Supplied: Department of Defence)
 Defence said climate change could magnify regional instabilities, causing security problems for Australia.
"Climate change can act as a 'threat multiplier'."
"Climate change may also eventually contribute to greater irregular migration pressure in vulnerable countries to Australia's north, potentially becoming a substantial security threat for Australia."
The Senate report concluded that "the consensus from the evidence (is) that climate change is exacerbating threats and risks to Australia's national security".
"These include sea level rise, bushfires, droughts, extreme rainfall events, and higher-intensity cyclones".
Leading aircraftman Aaron Townsend carries supplies to be flown to the Philippines for the Typhoon Haiyan relief effort. (Supplied: Glen McCarthy/ADF)
Currently serving senior defence figures in Australia rarely speak publicly about climate security.
"To do that would necessarily mean putting your head above the parapet, so to speak," said Associate Professor Matt McDonald from the University of Queensland.
"That's where I think there is a concern — that you don't want to be engaging in what is a toxic politics around climate change in Australia."
Admiral, Home Affairs see climate change as common threat
Contributing to the enquiry was the former head of the Australian Defence Force, Admiral Chris Barrie.
Admiral (ret.) Chris Barrie has raised the impact of a future threat of a Cape Town-style water crisis right across Asia. (ABC News)
When he was the Defence chief, it was his job to perceive future threats to Australia.
Now retired, the Admiral worries that climate change could cause huge security issues for the nation and no longer bound by office he is free to speak his mind.
Admiral Barrie has posed the scenario of what would happen if a Cape Town-style water crisis hit right across Asia, driven by receding glaciers in the Himalayan mountains.
"I'm talking China, around the Mekong river into Burma, Bangladesh, India, Pakistan. What will billions of people be doing about that problem?" he said.
"Well, one of the scenarios of course is, I think, they'll be looking for a new home."
Australia the Pacific pariah
Australia's stance on climate change and coal puts it increasingly at odds with its Pacific island neighbours, writes Wesley Morgan of the University of the South Pacific.
The former Department of Immigration and Border Protection, now called Home Affairs, has also followed the logic of threat multiplication in its Senate enquiry submission.
"Climate change is likely to exacerbate the complexity and unpredictability of existing migratory pressures around the world and for Australia," it wrote.
"In most cases, climate change-related migration will not eventuate as straightforward cause and effect, but will be shaped by the interaction of climate change with cultural, economic and political processes."

Environment's 'threat multiplier' gets on Defence radar
Military interest in the consequences of climate change can be traced back to a landmark report commissioned by the US Department of Defense in 2007.
The report, National Security and the Threat of Climate Change, was overseen by Sherri Goodman, a former deputy undersecretary of Defense.
She assembled a military advisory board of twenty retired admirals and generals who concluded that "projected climate change poses a serious threat to America's national security".
In contrast to the science, Donald Trump has said climate change was created by and for the Chinese in order to make US manufacturing uncompetitive. (Reuters: Carlos Barria, file photo)
Ms Goodman coined the term "threat multiplier" — meaning climate change may exacerbate existing threats rather than be a threat unto itself.
She reprised her 2007 message in a submission to Australia's recent Senate enquiry, advising Government to "recognise climate change as a global existential risk, and a direct threat to the national security of Australia".
The term and the ideas in the report had already caught on in Washington.
The Trump administration's current US Defense Secretary, General James 'Mad Dog' Mattis, at his confirmation hearing, seemed out of lock step with his soon-to-be commander-in-chief, stating:
"Climate change can be a driver of instability and the Department of Defense must pay attention to potential adverse impacts generated by this phenomenon."
Mr Trump has previously said the concept of climate change was created by and for the Chinese in order to make US manufacturing uncompetitive.

Study reinforces regional climate issues
A new study led by Australian scientist Dr Andrew King from the University of Melbourne paints a stark picture of this interaction between climate change and economics among Australia's neighbours in the Asia-Pacific region.
A map produced for the paper titled The Inequality of Climate Change from 1.5 deg C to 2 deg C of Global Warming shows a sea of red to Australia's north.
It indicates that poorer, tropical countries from India to Melanesia will notice a disproportionate amount of abnormal heat as temperatures increase by more than 1.5 degrees Celsius.
Dr King's research shows poorer, tropical regions will be disproportionally affected by climate change. (Supplied: Andrew King/University of Melbourne)
Comparatively wealthy Australia on the other hand is predicted to be once again the lucky country.
Increases in temperatures here would not be as noticeable.
"We're using a quantitative measure of local climate change and then overlaying that with population data and GDP data," Dr King said.
"What we're really showing, and this does compliment what studies have shown before, that it's the poorest who will be worst affected by climate change."

Links
at No comments: