Drought and climate change were the kindling, and now the east coast is ablaze


Multiple large, intense fires are stretching from Australia’s coast to the tablelands and parts of the interior.
AAP Image/Supplied, JPSS

Ross Bradstock, University of Wollongong and Rachael Helene Nolan, Western Sydney University

Last week saw an unprecedented outbreak of large, intense fires stretching from the mid-north coast of New South Wales into central Queensland.

The most tragic losses are concentrated in northern NSW, where 970,000 hectares have been burned, three people have died, and at least 150 homes have been destroyed.

A catastrophic fire warning for Tuesday has been issued for the Greater Sydney, Greater Hunter, Shoalhaven and Illawarra areas. It is the first time Sydney has received a catastrophic rating since the rating system was developed in 2009.

No relief is in sight from this extremely hot, dry and windy weather, and the extraordinary magnitude of these fires is likely to increase in the coming week. Alarmingly, as Australians increasingly seek a sea-change or tree-change, more people are living in the path of these destructive fires.




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Unprecedented state of emergency

Large fires have happened before in northern NSW and southern Queensland during spring and early summer (for example in 1994, 1997, 2000, 2002, and 2018 in northern NSW). But this latest extraordinary situation raises many questions.

It is as if many of the major fires in the past are now being rerun concurrently. What is unprecedented is the size and number of fires rather than the seasonal timing.

The potential for large, intense fires is determined by four fundamental ingredients: a continuous expanse of fuel; extensive and continuous dryness of that fuel; weather conditions conducive to the rapid spread of fire; and ignitions, either human or lightning. These act as a set of switches, in series: all must be “on” for major fires to occur.

Live fuel moisture content in late October 2019. The ‘dry’ and ‘transitional’ moisture categories correspond to conditions associated with over 95% of historical area burned by bushfire.
Estimated from MODIS satellite imagery for the Sydney basin Bioregion.

The NSW north coast and tablelands, along with much of the southern coastal regions of Queensland are famous for their diverse range of eucalypt forest, heathlands and rainforests, which flourish in the warm temperate to subtropical climate.




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These forests and shrublands can rapidly accumulate bushfire fuels such as leaf litter, twigs and grasses. The unprecedented drought across much of Australia has created exceptional dryness, including high-altitude areas and places like gullies, water courses, swamps and steep south-facing slopes that are normally too wet to burn.

These typically wet parts of the landscape have literally evaporated, allowing fire to spread unimpeded. The drought has been particularly acute in northern NSW where record low rainfall has led to widespread defoliation and tree death. It is no coincidence current fires correspond directly with hotspots of record low rainfall and above-average temperatures.

Annual trends in live fuel moisture. The horizontal line represents the threshold for the critical ‘dry’ fuel category, which corresponds to the historical occurrence of most major wildfires in the Bioregion.
Estimated from MODIS imagery for the Sydney basin Bioregion

Thus, the North Coast and northern ranges of NSW as well as much of southern and central Queensland have been primed for major fires. A continuous swathe of critically dry fuels across these diverse landscapes existed well before last week, as shown by damaging fires in September and October.

High temperatures and wind speeds, low humidity, and a wave of new ignitions on top of pre-existing fires has created an unprecedented situation of multiple large, intense fires stretching from the coast to the tablelands and parts of the interior.

More people in harm’s way

Many parts of the NSW north coast, southern Queensland and adjacent hinterlands have seen population growth around major towns and cities, as people look for pleasant coastal and rural homes away from the capital cities.

The extraordinary number and ferocity of these fires, plus the increased exposure of people and property, have contributed to the tragic results of the past few days.




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Communities flanked by forests along the coast and ranges are highly vulnerable because of the way fires spread under the influence of strong westerly winds. Coastal communities wedged between highly flammable forests and heathlands and the sea, are particularly at risk.

As a full picture of the extent and location of losses and damage becomes available, we will see the extent to which planning, building regulations, and fire preparation has mitigated losses and damage.

These unprecedented fires are an indication that a much-feared future under climate change may have arrived earlier than predicted. The week ahead will present high-stakes new challenges.

The most heavily populated region of the nation is now at critically dry levels of fuel moisture, below those at the time of the disastrous Christmas fires of 2001 and 2013. Climate change has been predicted to strongly increase the chance of large fires across this region. The conditions for Tuesday are a real and more extreme manifestation of these longstanding predictions.




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Whatever the successes and failures in this crisis, it is likely that we will have to rethink the way we plan and prepare for wildfires in a hotter, drier and more flammable world.The Conversation

Ross Bradstock, Professor, Centre for Environmental Risk Management of Bushfires, University of Wollongong and Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia’s drought relief package hits the political spot but misses the bigger point


Lin Crase, University of South Australia

There are two basic components to the Morrison government’s latest A$1 billion package response to the drought affecting large parts eastern Australia. One part involves extra subsidies to farmers and farm-related business. The other involves measures to create or upgrade infrastructure in rural areas.

Unfortunately, most funds will be misdirected and the response is unlikely to secure the long-term prosperity of regional and rural communities. This is a quick fix to a political problem, appealing to an important constituency. But it misses the point, again, about the emerging economics of drought.

Hitting the political target

The bulk of the A$1 billion package is allocated to a loan fund. The terms of the ten-year loans are more generous than what has been offered in the past. They are now interest-free for two years, with no requirement to start paying back the principal till the sixth year.

Farmers will be able to borrow up to A$2 million. In addition, loans of up to A$500,000 will also be available to small businesses in drought-affected towns.




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Because recipients are not having to pay the full cost, these loans are in practice a form of subsidy.

Subsidies are used by government to make more people undertake an activity than would otherwise be the case. In this case the government is offering a subsidy to keep farmers and small businesses owners doing what they’ve been doing, even though from an economic point of view this might not be very wise at all.

The question that should be asked is: “do we want more or fewer people to be involved in a farming activity that is vulnerable to drought?”

Most farming in Australia is completely reliant on rainfed crops and pastures. Rainfall is already highly variable. All the indicators from climate science is that rain will be even more unreliable in the future.




Read more:
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In addition, the agricultural industries currently drought affected are not just at the whims of rainfall. These industries are constantly changing and being affected by new technologies and market forces.

For most agricultural produce the key market force is price. Sure, some farms and farmers can carve out niche markets, but most farm businesses depend on producing at lowest cost. Increasingly, the farms that survive in a highly competitive global environment do this by exploiting economies of scale. Big farms are thus more profitable than small ones in the good times (such as when it rains); and during the tough times (such as during drought) they have more resources and deeper reserves to ride it out.

Ultimately, this means successful farms are continually getting bigger and small farmers are getting squeezed out.




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The data also support the view that the farmers who survive and are simultaneously exposed to drought ultimately become even more profitable, because of what they learnt about managing in a difficult environment.

This is not to argue drought is a good thing for any farm, but it does raise a serious question about any government policy that effectively encourages more people to keep doing something when global and technological forces would point to it being unsustainable.

So what’s the point?

The second component of the Morrison government’s relief response involves directing about A$500 million from existing regional infrastructure funds into building roads and other things into affected communities.

While many will welcome this on top of the the extension of loans to small business in country towns, the policy detracts from the serious questions that confront rural and regional communities.

The economics of agriculture has flow-on effects to towns, but it would be wrong to think all are impacted in the same way.




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Helping farmers in distress doesn’t help them be the best: the drought relief dilemma


As a general rule, when farmers sell up, they tend to leave from the small communities first. The upshot is that small communities get smaller, older and poorer as those least mobile are left behind. These people also generally require more, not less, public support. Mid-size communities tend to level out, while continuing to age. Large regional centres tend to grow and prosper.

The point is that each community requires different things from government. Genuine public goods like roads, health services and education are desperately needed and undersupplied in many cases. Providing cash to a few select businesses and grading a gravel road in this situation belies the complexity of the long-term challenges and fails to address serious issues.

An elderly retiree in a rural town might well ask why their local road or bridge is only upgraded during a drought. Surely, government should focus on providing legitimate public goods for the long term, regardless of the weather.The Conversation

Lin Crase, Professor of Economics and Head of School, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Government sets up concessional loan scheme for drought-hit small businesses



The business drought loans will be up to $500,000, and include a two-year interest free period.
AAP/Dan Peled

Michelle Grattan, University of Canberra

The government will provide concessional “drought loans” for small businesses dependent on agriculture, as well as improving the terms of loans under the existing scheme for farmers, in a package approved by cabinet on Wednesday.

Measures to be unveiled on Thursday also include hundred of millions of dollars of direct investment into communities.

The initiatives come after intense pressure on the Coalition to do more for those hit by one of the country’s worst-ever droughts, with Scott Morrison very sensitive to how the issue is playing not just in the regions but among metropolitan voters.

Costings were still being finalised late Wednesday but sources said the package was worth more than $500 million.

The business drought loans will be up to $500,000. They will include a two year interest free period and interest only payments for years three to five, with interest and principal repayments in years six to ten.

Those set to benefit would include harvesting and shearing contractors, carriers, stock and station agents, and businesses dealing in agricultural equipment and repairs.

Businesses not directly linked to the farming sector – such as the local hairdresser or newsagent – would not be eligible.

The loans will be made through the Regional Investment Corporation – a Commonwealth body – with a small business defined as one with 19 or fewer employees.

The loans will be available immediately and no legislation is needed.

The improved terms for farmers loans will be see up to two years interest free, interest only payments for years three to five, and interest and principal payments for years six to ten. The current arrangements are interest only for the first five years and principal and interest for the rest of the 10 year loan.

The former co-ordinator-general for drought, Stephen Day, told the government that concerns had been constantly raised with him about the survival of small businesses in areas in drought.

Morrison said these businesses had been forced to seek overdrafts or other finance.

“Rural communities can’t function without these small businesses – that’s why we’re stepping in to provide this extra support,” he said.

The government says its planned extra direct investment will flow into projects that boost local businesses and jobs.

Six more local government areas will be added to the Drought Communities Program, at a cost of $6 million, and another $122 million will be available for the 122 local councils which have already received support of $1 million each.

The program funds infrastructure and local activities. An extra $50 million discretionary fund will support additional councils when needed. But this will be after a review of the program early in the new year.

Some $200 million will be redirected from the Building Better Regions Fund to set up a Special Drought Round, providing up to $10 million per project in local government areas.

Supplementary payments will be made under the Roads to Recovery program for 128 local government areas in drought for upgrades and maintenance. This is a re-purposing of $138.9 million.

Drought minister David Littleproud said the federal package was not linked to any requirement for state funding, which would have carried the risk of the states not matching the money. But he called on state governments to provide some relief on rates and payroll tax.

“We’re going to cut the cheque and we’re going to get the money out, because that’s what these local economies need now. They need stimulation …. We’re not going to play politics, we’re going to get on with the job and deliver, and hopefully the states will complement us with things like rate relief and also payroll tax”.

Deputy Prime Minister Michael McCormack said: “This suite of measures go to the heart of what matters to these communities. From small businesses to primary producers, we are working with communities to take the pressure off one of the worst droughts in history.

“Not only is the government continuing to respond as the drought progresses, but we are working on measures to assist in the recovery when the rains come, which includes the government’s billion dollar investment in water infrastructure.”

Agriculture Minister Bridget McKenzie said: “I know our farmers and our communities are doing it really tough right now but despite the current drought Australian agriculture has a bright future”.The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A national drought policy should be an easy, bipartisan fix. So why has it taken so long to enact a new one?



The Coalition has been promoting its $7 billion drought relief package, but critics say what’s needed is a more effective national drought policy.
Dan Peled/AAP

Linda Botterill, University of Canberra

In a country as dry as Australia, surely it is a no-brainer that we have in place a coordinated, national drought response that can be rolled out the same way that the Natural Disaster Relief and Recovery Arrangements are triggered when the country experiences cyclones, floods or bushfires.

Drought used to be part of these arrangements but, for good policy reasons, was removed in 1989.

Our last attempt at national drought policy

Once upon a time, Australia had a national drought policy. It was enacted in 1992 following a comprehensive review and report by an independent panel, the National Drought Policy Review Task Force, and detailed negotiations between Commonwealth and state ministers and their officials.

The policy included commitments by both state and Commonwealth governments to implement a coordinated and comprehensive package of programs covering drought preparation and response.

At the Commonwealth level, these measures were centred around:

  • the controversial “exceptional circumstances” provisions of its revised Rural Adjustment Scheme, which were aimed at supporting farm businesses by subsidising up to 100% of the interest paid on commercial loans.

  • a farm household support scheme that provided short-term income support to farmers and also offered grants for those who decided to leave the land.

  • farm management bonds, later known as farm management deposits, that allowed farmers to set aside pre-tax income they could later draw on in times of need.

  • a drought relief payment (added to the policy in 1994) that provided income support for farmers in areas declared to be experiencing “exceptional circumstances” drought. By May 1995, over 10,000 families were accessing this payment every month.

Grain feed left for sheep grazing on a failed crop in NSW.
NSW drought stock/AAP

Flaws in the policy

As anyone familiar with these programs will know, the exceptional circumstances program was plagued by problems.

The first was the lack of clarity around defining when a drought moved from a “normal” situation that was expected to be managed by farmers, to an “exceptional” situation with which even the best manager could not be expected to cope.

The definition of an “exceptional circumstances” drought became the subject of ongoing debate, along with concerns that drought assistance was based on administrative boundaries, leading to inequities that became known as the “lines on maps” problem.




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The second issue was the amount of information farmers were required to provide in order to demonstrate eligibility for “exceptional circumstances” assistance. The process was considered onerous and time-consuming.

Amid these concerns, a comprehensive review of drought policy was conducted in 2008 by the Productivity Commission. This was accompanied by a report by the Bureau of Meteorology and CSIRO on the likely impact of climate change on the frequency and severity of droughts in Australia, and an independent report on the social impact of drought.

Following the review, the government decided to end the “exceptional circumstances” program in 2009. This effectively gutted the national drought policy.

Since then, there has been no further attempt at developing a comprehensive, predictable drought policy response from the federal or state governments. There have been intergovernmental National Drought Agreements, but these have done little more than restate the principles underpinning the country’s drought policy since 1992.

In recent years, the Coalition government has appointed a drought envoy, Barnaby Joyce, and drought coordinator-general, Stephen Day, to study the impact of drought on farmers and recommend possible solutions, but we have yet to see what either has come up with.

Drought envoy Barnaby Joyce says he has sent drought reports directly to Scott Morrison, but these have not yet been made public.
Lukas Coch/AAP

Providing meaningful, timely and predictable support

Much of the criticism levelled at the government’s response to the current drought relates to its ad hoc and knee-jerk nature. This reactive way of dealing with drought highlights the need to return to a more predictable approach. This would avoid perceptions of pork barrelling and provide certainty to farmers about what support is available and under what circumstances.

A new national drought policy needs to take several forms. First, it needs to support farmers to prepare for drought before it happens. This is one area where the current policy has been moderately successful.

As of August 2019, Australian farmers had set aside a total of $5.809 billion in farm management deposits. These deposits have encouraged farmers to manage financial risk by building up cash reserves in high-income years, which they could then use during times of drought.

Individual farmers can currently hold a total of $800,000 in deposits. One possible improvement is to raise the ceiling on annual deposits in the years following drought recovery to allow a rapid rebuilding of cash reserves.

Second, a strong drought policy needs to provide support to all farmers during drought, not just those who have accumulated sufficient deposits to help them ride out the lean years.

In recent years, many farmers have taken advantage of long-term, low-interest loans to help during drought, and some have called for zero-interest loans to be made available, as well. But loans are not an ideal solution, as repayments are generally required even when farm incomes remain low.

An alternative to low- or no-interest loans are income contingent loans. Similar to the HECS-HELP scheme in higher education, these types of loans only require repayment when the borrower can afford to do so.

This would not only give farmers greater flexibility when it comes to repayment, it would also greatly reduce the extensive red tape that strangled the old “exceptional circumstances” scheme.




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Third, we need a serious rethink of the way we provide income assistance to farmers in a broader sense. Providing income support to farmers who are asset-rich, for instance, raises questions about fairness when compared with poor people in cities who are struggling to get by on Newstart payments.

This imbalance has come into stark focus in recent weeks, particularly on social media, as government ministers have discussed the introduction of drug testing for Newstart recipients, and in the debate around the Indue card.

There has been no serious attempt in the past 45 years to measure the extent of poverty among farmers. We can develop more appropriate and equitable income-support policies if we can better understand the genuine nature of their need.

The elephant in the room

While the government has assiduously avoided making the link, an effective national drought policy also cannot be divorced from discussions about climate change.

The 2008 Productivity Commission report was pretty clear in its conclusions about the impact of climate change on drought in Australia. A growing number of farmers are now acknowledging this reality. Denying the need for serious consideration of climate change is not doing our agricultural producers any favours.




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Developing an effective national drought policy is hard work. But in another sense, it should also be easy. This is because, unlike many other areas of government policy, it can be bipartisan.

Although the National Party has historically been aligned with rural voters, all parties are broadly sympathetic to farmers and value their contributions to the economy and, importantly, our national identity. The public also generally regards farmers positively and is responsive to their plight when they are faced with hardship.

As such, this should be one area where our politicians can come together to develop a coherent national response — one that is known in advance, forward-looking, equitable with other income-assistance programs in the community, and provides meaningful support before, during and after drought.The Conversation

Linda Botterill, Professor in Australian Politics, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Just because both sides support drought relief, doesn’t mean it’s right


Lin Crase, University of South Australia

The bipartisan parliamentary vote to transform the A$3.9 billion Building Australia Fund into a pot of cash to drought-proof Australia, the Future Drought Fund, should not be taken as universal endorsement.

Labor opposed the idea before caving in, saying it did not “want to be painted as a party that opposes support for farmers”.

Rather, it simply shows that Australian politicians coalesce on some things: few miss the opportunity to be photographed with an affectionate child, and even fewer are willing to be critical of public funds being handed to drought-stricken farmers.

But support something (or feeling too scared not to oppose something), doesn’t necessarily make it the right policy.




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Drought is inevitable, Mr Joyce


Australian governments have sought to drought-proof parts of inland Australia through publicly funded irrigation schemes for much of the past century.

Whenever dryland farmers experienced drought, they were viewed as having experienced a natural disaster, even though the variability of dryland rains was well understood.

Then, from the 1960s, things changed.

First there was a growing realisation that public monies spent on irrigation were not the best means of dealing with a variable climate.

We’ve moved away from thinking about drought as disaster

Second, governments started to describe drought differently, culminating in a 1992 National Drought Policy that required farmers to be more self-reliant and absorb the impacts of drought as something to be expected.

The decades that followed continued this trend with all states and the Commonwealth agreeing on national principles in 2013. Concessional loans and a farm management deposit scheme with taxation advantages were available to help farmers, but would only be useful to those that were viable in the long term.

A Farm Household Allowance, set at the level of Newstart and available for up to four years in return for setting out a plan to improve the farmer’s financial circumstances, was also introduced in 2015 and refined in 2018.

Part of the thinking was that climate change is expected to make droughts more common and severe, although there are good reasons for encouraging adaptation to the existing climate in any case.




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Helping farmers in distress doesn’t help them be the best: the drought relief dilemma


However, getting the balance right between “supporting” farm businesses and encouraging them to adapt and be self-reliant isn’t straightforward, especially when the climate and political cycles coincide.

It’s hard to imagine politicians being fiscally prudent when they know they have access to a drought slush fund and are heading into an election during a drying phase.

So, what’s wrong with the new drought fund?

First, there is mounting evidence that farm businesses can actually benefit from drought in the longer term. This seems to occur because businesses that go through a drought develop coping strategies that when invoked in good years produce much greater profits.

That is not to say that droughts are financially a good thing – but it does mean that shielding farm businesses from drought runs the risk that they will not adapt.

Second, an obsession with drought undoes much of the good work done in reclassifying it as something to be expected rather than a natural disaster. Nearly all of the natural disaster payments made in the decade leading up to 2012-13 – one of the driest on record – were spent on rebuilding after floods and storms rather than droughts.

Third, while repurposing the Building Australia Fund as the Future Drought Fund is designed to appeal to rural and regional voters, it is unlikely to help them. Agriculture simply does not generate the jobs that it once did and public pronouncements about drought-proofing will not change the underlying economics of farm businesses and regional communities.




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Farming is generally helped by scale, and that means bigger farms with bigger machines displacing smaller farms. The upshot is fewer jobs and the shutdown of small towns, allowing only the larger regional centres to survive. Finding ways to manage this social phenomenon should be the priority rather than shielding farms from drought.

But it’s hard to be optimistic. Politicians love handing cheques to farmers as much as they love photographs with adoring children.The Conversation

Lin Crase, Professor of Economics and Head of School, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This is why nuking a hurricane will not work, Mr Trump


Liz Ritchie-Tyo, UNSW

President Donald Trump has reportedly suggested on more than one occasion that the US military explode nuclear bombs inside hurricanes to disrupt them before they reach land.

As reported in National Geographic, this is not the first time a suggestion like this has been made – although Trump now denies having said it.

On the surface, it would seem like a simple solution to the devastation that occurs in the US each year during the hurricane season. However, there are several problems with this idea.




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What is a hurricane?

Hurricanes are low-pressure weather systems covering an area of more than 500,000km². They form over warm tropical oceans, which are their primary energy source. The low pressure at the centre of the hurricane – the eye – draws in the surrounding warm, moist air. This air then rises and condenses into deep thunderstorm clouds surrounding the centre – the eyewall – and also in cloud bands spiralling out from the eye called rainbands.

As the air is pulled into the eye, Earth’s rotation causes it to spin cyclonically – anticlockwise in the northern hemisphere and clockwise in the southern hemisphere. The continuous supply of air into the deep thunderstorms surrounding the eye allows the hurricane to intensify until it reaches a steady state of equilibrium with the oceans and the environment.

Would a nuclear bomb put a dent in a hurricane?

The average hurricane can be likened to a very inefficient heat engine. As the warm moist air rises, it releases heat energy through the formation of clouds and rain at a rate of about 5.2 x 10¹⁹ joules per day. Less than 10% of this heat is then converted into the mechanical energy of the wind.

To give some perspective of this energy, the heat released in a hurricane is equivalent to a 10-megatonne nuclear bomb exploding every hour. This energy is also on the order of the global energy consumption in 2016, according to the United States Energy Information Agency.

It seems unlikely that exploding a bomb in the hurricane would make much impact on such a powerful weather system, and it is impossible to run controlled experiments to determine whether it would.

Not to mention that there could be shocking effects from the fallout of radioactive material from such an explosion. These materials would be transported widely via the trade winds through the lower levels of the atmosphere, and potentially around the entire planet in the stratosphere – similar to the effects from the volcanic fallout from Mount Pinatubo in the Philippines in 1991.

Have people tried to stop hurricanes before?

There have been previous attempts to modify the impacts of hurricanes. Between 1962 and 1983 the US government funded experimental research on hurricane modification known as Project STORMFURY. The fundamental premise was, because the potential of damage from hurricanes increases rapidly with the hurricane’s wind speed, a reduction in wind speed of as little as 10% could make a large difference in the impacts when hurricanes reach land. By seeding the air outside the eyewall with silver iodide, a chemical used to seed clouds, it was thought a new ring of thunderstorms may develop outside the eyewall – robbing it of energy and weakening the hurricane.




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Modification was attempted in four hurricanes on eight different days. On four of those days, a 10-30% reduction in wind speed was measured. The lack of response on the other fours days was initially interpreted to be the result of faulty execution of the experiment, but was later attributed to an imperfect understanding of the microphysics of clouds in hurricanes.

Successful cloud seeding using silver iodide requires that supercooled water droplets freeze onto the silver iodide seeds.

Recent observations show hurricanes have too many naturally occurring ice crystals and too few supercooled water droplets for cloud seeding to be effective. So any change in hurricane wind speed observed during the STORMFURY experiments was almost certainly due to the natural behaviour of hurricanes rather than human intervention.

Although Project STORMFURY was abandoned, the hurricane observation program is still run under the Hurricane Research Division of the National Oceanic and Atmospheric Administration (NOAA). The original aircraft used in Project STORMFURY were replaced in the 1970s by WP-3D aircraft, which still reside under NOAA and are operated by its officers.




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Hurricanes to deliver a bigger punch to coasts


The observations collected by these aircraft continuously over a period of more than 60 years has helped improve hurricane forecasting. Furthermore, these observations have allowed researchers to develop vital insights into the structure, intensity, and physical processes of this most destructive of natural phenomena.The Conversation

Liz Ritchie-Tyo, Associate Professor, School of Physical, Environmental, and Mathematical Sciences, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The stubborn high-pressure system behind Australia’s record heatwaves



File 20190124 135136 p47dl4.jpg?ixlib=rb 1.1
Parts of Australia have broken multiple heat records over the past week.
Vicki/Flickr, CC BY-NC-SA

Steve Turton, CQUniversity Australia

If you think the weather this month has been like Groundhog Day (albeit much hotter), you’d probably be right! Much like a stuck record, weather systems seem to have stalled over most of the country.

Brisbane residents are questioning the lack of rain, storms and heat. Darwin has just endured its second-latest monsoon onset on record after weeks of heat and humidity. Interior towns and cities have experienced significantly hot weather with a number of new maximum and minimum temperature records broken, along with records for consecutive days over 35℃.




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Perth has largely escaped the heat so far this summer, while Sydney and Hobart have had a mixed bag. Coastal sea breezes have tempered conditions in the south and southeast of the continent. However, heatwaves are forecast for Melbourne and much of the southeast, with the arrival of strong, hot northerly winds. This will also bring extreme or severe fire weather conditions in many areas, including Tasmania. Adelaide, meanwhile, has sweltered through the hottest day on record for any Australian capital.


Bureau of Meteorology

These weather patterns across the country are largely due to a stubborn blocking high-pressure system that has remained over the Tasman Sea since early January, affecting weather on both sides of the ditch. This type of strong high-pressure system typically forms further south than usual, and remains almost stationary for an extended period, thus blocking the west-to-east progression of weather systems across southern Australia.




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Sometimes, these blocking highs position themselves over the Great Australian Bight. They can occur at any time of year, and can stay in the Australian region from several days to several weeks.

This schematic shows a ‘blocking high’ preventing weather systems moving across Australia.
Understanding Climate Change in Australia report

Winds rotate anticlockwise around high-pressure systems in the Southern Hemisphere. On the northern flank of the blocking high, southeast trade winds have been affecting northern New South Wales and eastern Queensland due to a persistent ridge of high pressure. These winds have been largely cool and dry, with only the far north of Queensland experiencing significant showers. The ridge has kept the inland trough further west over inland NSW and Queensland, preventing normal afternoon thunderstorm activity in the inland, and adding to the woes of the extended drought.

Cool, moist weather from the Southern Ocean is being displaced southeast by the blocking high, resulting in prolonged continental heatwaves and lack of rain. On the western flank of the blocking high, hot dry northerly winds from the arid centre are pushing through South Australia and Victoria, generating heatwave conditions.




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Across the ditch, cooler and drier southerly winds are affecting much of New Zealand. Only the southwest of the South Island is getting any significant rain due to persistent moist westerlies on the southern flank of the blocking high.

An unusually strong ridge of high pressure across Queensland, extending up to Cape York, has kept the monsoon trough north of the continent. This pattern is forecast to change as a deep tropical depression forms in the Gulf of Carpentaria over the coming days and moves south into northern Queensland. Unfortunately, the stubborn ridge of high pressure over central Queensland is likely to block the rain-bearing low from moving much further south over drought-stricken parts of inland Queensland and NSW.




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Coping with heat waves: 5 essential reads


While parts of the country have sweltered, the far southwest of Australia has experienced cooler and wetter than average conditions this month. Cape Leeuwin, Australia’s most southwesterly point, set a 123-year daily rainfall record for January, recording a massive 57mm of rainfall.


Bureau of Meteorology

In the short term, there is no indication that the blocking high will break down or move eastward. Forecasters on both sides of the Tasman expect the pattern to continue until February at least.




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The Conversation


Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sydney storms could be making the Queensland fires worse


Claire Yeo, Australian Bureau of Meteorology

A strong low-pressure system has meant severe thunderstorm and hail warnings are in effect for much of the New South Wales South Coast. At the same time, very dry conditions, strong winds and high temperatures are fuelling dozens of bushfires across Queensland.

The two events are actually influencing each other. As the low-pressure system moves over the Greater Sydney area, a connected wind change is pushing warm air (and stronger winds) to Queensland, worsening the fire conditions.




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These lows over NSW are the kind we might see a couple of times a year – they’re not just regular weather systems, but neither are they massively out of the ordinary.

However, when combined with the current record-breaking heat in Queensland, the extra wind is creating exceptionally dangerous fire conditions. Queensland’s emergency services minister, Craig Crawford, has warned Queenslanders:

We are expecting a firestorm. We are expecting it to be so severe that it won’t even be safe on the beach […] The only thing to do is to go now.

Conditions in Queensland

At least 80 bushfires were burning in Queensland on Wednesday, with more than a dozen fire warnings issued to communities near the Deepwater blaze. Queensland Police Deputy Commissioner Bob Gee said that “people will burn to death” unless they evacuate the area.

These fires have come during a record-breaking heatwave. On Tuesday Cooktown recorded 43.9℃, beating the previous November high set 70 years ago by more than two degrees. Cairns has broken its November heatwave record by five whole degrees.

Grasslands and forests are very dry after very little rain over the past two years. Adding to these conditions are strong winds, which make the fires hotter, faster and harder to predict. This is where the storm conditions in NSW come in: they are affecting air movements across both states.

NSW low is driving winds over Queensland

A large low-pressure system, currently over the Hunter Valley area, is causing the NSW storms. As it moves, it’s pushing a mass of warm air ahead of it, bringing both higher temperatures and stronger winds across the Queensland border.

Once the low-pressure system moves across the Hunter area to the Tasman Sea east of Sydney, it will drag what we call a “wind change” across Queensland. This will increase wind speeds through Queensland and temperatures, making the fire situation even worse.

This is why emergency services are keeping watch for “fire tornado” conditions. When very hot air from large fires rises rapidly into a turbulent atmosphere, it can create fire storms – thunderstorms containing lightning or burning embers. Strong wind changes can also mean fire tornadoes form, sucking up burning material. Both of these events spread fires quickly and unpredictably.




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What does this mean for the drought

Unfortunately, it’s not likely the heavy rains over NSW will have a long-term effect on the drought gripping much of the state. While very heavy rains have fallen over 24 hours, the drought conditions have persisted for years.




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The wet weather may bring some temporary relief, but NSW will need much more rain over a longer period to truly alleviate the drought.

In the meantime, the Bureau of Meteorology will be monitoring the Queensland situation closely. You can check weather warnings for your area on the bureau’s website.The Conversation

Claire Yeo, Supervising Meteorologist, Australian Bureau of Meteorology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Explainer: how a dust storm, and hazardous air quality, can harm your health


Mark Patrick Taylor, Macquarie University and Cynthia Isley, Macquarie University

A major dust storm swept through Sydney and regional New South Wales this week. Red skies over Broken Hill on Wednesday night and Sydney on Thursday resembled those seen during intense bushfire activity and the massive 2009 dust storm.

The NSW government updated its air quality index to “hazardous”. People were advised to stay indoors unless it is essential to go outside, minimise strenuous physical activity and seek emergency medical assistance if they experience breathing difficulties, chest pains, or if other serious health concerns arise.

The hazardous air quality warning arose because fine dust levels were high relative to Australian air quality standards. Air quality levels of PM10 – particles at or less than 10 microns (µg) – were more than twice the Australian standard, of 50 µg/m³ measured over a 24-hour period, on Friday morning. They remained high throughout the day.

Perhaps of greater concern are the smaller PM2.5 dust particles, which were above the Australian standard of 25 µg/m³ at St Marys in Sydney’s west on Friday morning. Fine PM2.5 dust particles can penetrate deep into the lungs and cause respiratory difficulties. Short-term exposures aggravate asthma, increasing the number of emergency department visits, as well as causing wheezing and breathing difficulties.

Even for those not affected by asthma, exposure can cause coughing, a sore throat and a runny nose. Elevated dust exposure can also aggravate heart conditions. For example, increased short-term exposure to both PM10 and PM2.5 has been linked to increased death and hospitalisation rates due to heart disease, arrhythmias (palpitations) and stroke.

The city of Newcastle is experiencing much worse conditions. On Friday morning PM10 levels were four times the Australian standard of 50 µg/m³ due to additional smoke particles from local bushfires. Throughout the day PM2.5 levels in Newcastle have remained just below the maximum acceptable upper value of 25 µg/m³.

Fine dust particles are usually too small to see individually but high concentrations make them visible as a brown haze. Even as the dust begins to clear, the unseen fine particles outside or even inside your house can still present a health risk.




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It’s advisable to use any prescribed relieving medications and seek medical advice if symptoms do not improve. For those who own an air conditioner, it may be appropriate to use it as long as the fresh air intake is closed and the filter is clean, preventing particles from being drawn into the home.

It is also important to keep an eye on air quality, which can be done in real-time via the NSW government’s air quality monitoring network.

The previous major dust storm in 2009 was made of predominantly natural elements – aluminium, silicon and iron. These originate from desert soils and did not contain significant concentrations of toxic elements. The current dust storm is likely similar in composition.

While there is some evidence the source and composition of dust has health implications, the most critical factor is the size of the particles. Evidence shows there is no safe level of fine PM2.5 dust.

Dust storms like this and the one in 2009 are unlikely to present a long-term health risk. However, they are concerning in the short term, especially for the elderly, people with pre-existing respiratory conditions and children, who breathe more air per kilogram of body mass than adults.

A health impact assessment of the 2009 dust storm showed marked increases in emergency admissions for asthma and respiratory conditions but no significant increase in cardiovascular (heart and vessel) hospital admissions. The age groups most affected were those known to be most vulnerable – people older than 65 and those aged five and younger.




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A similar situation is being experienced in California, where wildfires are causing high concentrations of dust and smoke in the air and significant concerns about human health.

Australia generally enjoys good air quality, which is not the case for many lower- to middle-income countries. According to the World Health Organisation (WHO), more than 600,000 children died in 2016 due to air pollution.

Air quality is a global public health issue. Around 91% of the world’s population live in areas where the WHO’s fine particle (PM2.5) guidelines are not met.


For those concerned about dust, Macquarie University’s DustSafe program will provide information on the dust in your home free of charge.The Conversation

Mark Patrick Taylor, Professor of Environmental Science, Macquarie University and Cynthia Isley, Researcher, Macquarie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We must look past short-term drought solutions and improve the land itself


David Lindenmayer, Australian National University and Michelle Young, Australian National University

With drought ravaging Australia’s eastern states, much attention has been given to the need to provide short-term solutions through drought relief. But long-term resilience is a vital issue, particularly as climate change adds further pressure to farmers and farmland.

Our research has found that helping farmers improve the rivers, dams, native vegetation and trees on their land increases productivity, the resilience of the land to drought, and through this the health and well-being of farmers.




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Now is the time to invest more heavily than ever in vital networks in regional Australia, such as Landcare and natural resource management groups like Local Land Services and Catchment Management Authorities.

Research shows that trees, dams and native vegetation are essential to increase agricultural productivity.
Shutterstock/Olga Kashubin

Growing pressures on agricultural land

Some researchers suggest that up to 370 million hectares of land in Australia and the Pacific is degraded. This diminished productivity across such a large area has significant implications for the long-term sustainability of agricultural production.

Australia also has one of the worst records for wildlife diversity loss, including extensive loss of biodiversity across much of our agricultural land. The problems of degradation and biodiversity loss are often magnified under the pressure of drought.




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The good news is that there are ways to strengthen the resilience of the farmland. One key approach is to invest in improving the condition of key natural assets on farms, like shelter belts, patches of remnant vegetation, farm dams, and watercourses.

When done well, active land management can help slow down or even reverse land degradation, improve biodiversity, and increase profitability.

Better lands make more money

Many studies have shown improving the natural assets on an farm can boost production, as well as avoid the costs of erosion and flood control. For example, restored riverbank vegetation can improve dry matter production in nearby paddocks, leading to greater milk production in diary herds and up to a 5% boost in farm income.

Lines of trees, called windbreaks or shelterbelts, can protect and improve the fields next to them.
Peter Fenda/Flickr, CC BY-NC-SA

Similarly, shelter belts (tree lanes planted alongside paddocks) can lower wind speeds and wind chill, and boost pasture production for livestock by up to 8%, at the same time as providing habitat for biodiversity.




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Our own long-term work with farmers who invested in their natural assets prior to, or during, the Millennium Drought in New South Wales suggests these farmers are currently faring better in the current drought.

Investing in resilience for the long-haul

Groups like Landcare bring their expertise to land management.
Shutterstock/Darryl Smith

Well-supported and resourced organisations like Landcare groups are pivotal to supporting effective land management, which improves degraded land and helps farmland (and farmer) through tough times.

However, Landcare and other natural resource management agencies have been subject to major budget cuts over the past decade.

They are also a key part of the social fabric of rural communities, bringing together landowners to exchange ideas and support each other. Indeed, the Australian Landcare model is so well regarded globally it has been adopted in 22 other countries.




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This drought is a critical decision point. The need to invest in maintaining and improving our vegetation, water and soil has never been more apparent than it is now. We have a chance to determine the long-term future of much of Australia’s agricultural land.The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University and Michelle Young, Director, Sustainable Farms, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.