We found a secret history of megadroughts written in tree rings. The wheatbelt’s future may be drier than we thought


An almost-dry dam, surrounded by wheat fields, in WA’s wheatbelt region.
Shutterstock

Alison O’Donnell, The University of Western Australia; Edward Cook, Columbia University, and Pauline Grierson, The University of Western AustraliaDrought over the last two decades has dealt a heavy blow to the wheatbelt of Western Australia, the country’s most productive grain-growing region. Since 2000, winter rainfall has plummeted by almost 20% and shifted grain-growing areas towards the coast.

Our recent research, however, found these dry conditions are nothing out of the ordinary for the region.

In fact, after analysing rings in centuries-old tree trunks, we found the region has seen far worse “megadroughts” over the last 700 years. Australia’s instrumental climate records only cover the last 120 or so years (at best), which means these historic droughts may not have previously been known to science.

Our research also found the 20th century was the wettest of the last seven centuries in the wheatbelt. This is important, because it means scientists have likely been underestimating the actual risk of drought – and this will be exacerbated by climate change.

What we can learn from ancient trees

We estimate the risk of extreme climate events, such as droughts, cyclones and floods, based on what we know from instrumental climate records from weather stations. Extending climate records by hundreds or even thousands of years means scientists would be able to get a much better understanding of climate variability and the risk of extreme events.

_Callitris_ trees overlooking a salt lake
Callitris trees overlooking a salt lake. We pulled a column of wood from these tree trunks to investigate past climate changes in the region.
Alison O’Donnell, Author provided

Thankfully we can do just that in many parts of the world using proxy records — things like tree rings, corals, stalagmites and ice cores in Antarctica. These record evidence of past climate conditions as they grow.

For example, trees typically create a new layer of growth (“growth ring”) around their trunks, just beneath the bark, each year. The amount of growth generally depends on how much rain falls in the year. The more it rains, the more growth and the wider the ring.

Tree rings of Callitris columellaris.
Alison O’Donnell, Author provided

We used growth rings of native cypress trees (Callitris columellaris) near a large salt lake at the eastern edge the wheatbelt region. These trees can live for up to 1,000 years, perhaps even longer.

We can examine the growth rings of living trees without cutting them down by carefully drilling a small hole into the trunk and extracting a column (“core”) of wood about the size of a drinking straw. By measuring the ring widths, we developed a timeline of tree growth and used this to work out how much rain fell in each year of a tree’s life.

This method allowed us to reconstruct the last 668 years of autumn-winter rainfall in the wheatbelt.

A tree trunk with a blue scientific instrument attached
A tree borer – a hollow drill used to extract ‘cores’ of wood from tree trunks.
Alison O’Donnell, Author provided

A history of megadroughts

One of the most pressing questions for the wheatbelt is whether the decline in autumn-winter rainfall observed in recent decades is unusual or extreme. Our extended record of rainfall lets us answer this question.

Yes, rainfall since 2000 was below the 668-year average — but it was not extremely low.

The last two decades may seem particularly bad because our expectations of rainfall in the wheatbelt are likely based on memories of higher rainfall. But this frequent wet weather has actually been the anomaly. Our tree rings revealed the 20th century was wetter than any other in the last 700 years, with 12% more rain in the autumn-winter seasons on average than the 19th century.




Read more:
500 years of drought and flood: trees and corals reveal Australia’s climate history


Before the 20th century, the wheatbelt saw five droughts that were longer and more severe than any we’ve experienced in living memory, or have recorded in instrumental records. This includes two dry periods in the late 18th and 19th centuries that persisted for more than 30 years, making them “megadroughts”.

While the most recent dry period has persisted for almost two decades so far, rainfall during this period is at least 10% higher than it was in the two historical megadroughts.

This suggests prolonged droughts are a natural and relatively common feature of the wheatbelt’s climate.

An aerial view of the tree-ring site, home to trees that can live up to 1,000 years.
Hannah Etchells, Author provided

So how does human-caused climate change play into this?

It’s likely both natural climate variability and human-caused climate change contributed to the wheatbelt’s recent decline in rainfall. Unfortunately, it’s also likely their combined influence will lead to even less rainfall in the near future.

What happens now?

Our findings have important implications for assessing the risk of drought. It’s now clear we need to look beyond these instrumental records to more accurately estimate the risk of droughts for the wheatbelt.

But currently, proxy climate records like tree rings aren’t generally used in drought risk models, as there aren’t many of them in the regions scientists want to research.

Improving risk estimates leads to better informed decisions around preparing for and managing the effects of droughts and future natural disasters.




Read more:
To help drought-affected farmers, we need to support them in good times as well as bad


Our findings are a confronting prospect for the future of farming in the wheatbelt.

Australian farmers have shown tremendous innovation in their ability to adapt in the face of drought, with many shifting from livestock to crops. This resilience will be critical as farmers face a drier, more difficult future.The Conversation

Alison O’Donnell, Research Fellow in Dendroclimatology, The University of Western Australia; Edward Cook, Ewing Lamont Research Professor, Director Of Tree-Ring Lab, Columbia University, and Pauline Grierson, Director, West Australian Biogeochemistry Centre, The University of Western Australia

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

Writing the WA wheatbelt, a place of radical environmental change


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A message ploughed in the land calls on the federal government to help drought-affected farmers near the wheatbelt town of Kondinin in 2001.
Liza Kappelle/AAP

Tony Hughes-D’Aeth, University of Western Australia

What can creative literature tell us about radical environmental change? Most people accept that literature can be closely connected to places. Whether it is Dickens’s London or Hardy’s Wessex, we also accept that imaginative works deliver something about the nature of place that does not necessarily come to us by any other means. The Conversation

How then does this work in Australia? I have spent the past decade writing a literary history of the Western Australian wheatbelt and have sought in various ways to answer this question.

It is a regional literary history that nevertheless encompasses some of the nation’s finest writers — Albert Facey, Dorothy Hewett, Peter Cowan, Jack Davis, Randolph Stow, Elizabeth Jolley, Tom Flood, John Kinsella. Facey’s A Fortunate Life (1981) is a landmark in Australian autobiography; Hewett, Cowan and Stow helped define literary modernism in Australia; Jack Davis was a leading figure in the Aboriginal literary renaissance; and Jolley’s The Well (1986) and Flood’s Oceana Fine (1990) both won the Miles Franklin literary award.

What unites these works? Is it simply a quirk of fate that a sparsely populated hinterland in Australia’s most isolated state produces a body of literature that rivals in many ways the literary outputs of the great Australian metropolitan centres in Melbourne and Sydney?

For the answer to this question one has to understand the history of the WA wheatbelt. In two 30-year periods (1900-1930 and 1945-1975) an area of land roughly the size of Britain was stripped of its native vegetation for the production of grain and livestock. It is a crescent of land that begins just north of Geraldton on the west coast and sweeps south and east to Esperance on the south coast.

When the Swan River Colony was founded in 1829, six years before Melbourne, it was with the intention of forming an agricultural colony of closely settled yeoman farmers, who would own their own land and congregate in small, nicely spaced villages.

The clearing of the wheatbelt during the 20th century.

However, the antique soil of WA bore almost no resemblance to the fertile soils of recently glaciated northern Europe. Four to five more or less rainless months, where dry desert winds blow steadily across the vegetation was also an unprecedented challenge to farming methods learned in the British Isles. Lastly, there were almost no rivers to speak of, and permanent summer water was a rare commodity.

WA Government land advertisement from 1904.

For all these reasons, the agricultural dream of WA remained largely unrealized. The game-changing event was the goldrush of the 1890s. The population of the colony trebled between 1889 and 1896, from 44,000 to 138,000.
Knowing that the gold would be dug out before too long but wanting to capture this new cache of colonists, the colonial government passed the Homesteads Act in 1893 to parcel out land, and established an Agricultural Bank in 1894 to finance farmer-settlers. An army of land surveyors fanned out through the southwest and provisions for water, fertilizer and rail transit were quickly put into motion. Towns were gazetted, one-teacher schools popped up and WA took the lead in distance learning.

Albert Facey’s uncle Archie McCall had come over from South Australia to work the goldfields and was one of those who leapt at the land offer. Dorothy Hewett’s grandparents had made their money selling goods to diggers heading out to the goldfields at Kalgoorlie and Coolgardie and with this they purchased an extensive parcel of prime land at Yealering not far from McCall’s farm at Wickepin.

The dream refracted

What we get in both of these very different writers is a distinct picture of the dream of the wheatbelt. It is this dream — a settler-colonial ideology of farming independence — that we see refracted through the wheatbelt writers all the way through the 20th century.

The animating vision of the wheatbelt was an amalgam of ideals. On the one hand, it appealed to the basic material prospect of upward mobility. In the late 19th and early 20th century, opportunities for advancement through education were not generally available.

But the wheatbelt vision seemed even more deeply situated than this, offering itself as an antidote to the ills of modern city life. As the various states all moved to convert low-yield pastoral production to high-yield cash-cropping, there emerged a veritable ideology of wheat in the post-Federation years, and right through to the Depression.

C.J. Dennis joined the chorus in his bouncy ballad simply called Wheat from 1918:

Tho’ it ain’t a life o’ pleasure,

An’ there’s little time for leisure,

It’s contentin’, in a measure, is the game of growin’
Wheat.

Dennis and others helped to drag crop-farming away from its associations with European peasant drudgery and into the noble task of nation-building and feeding the “bread-eating” (i.e. European or European-derived) countries of the world.

Dorothy Hewitt, 1965.
University of Western Australia archives.

For Facey, even though his memoir was not published until 1981 (the year before he died), the dream of the wheatbelt and the ideology of wheat remain preserved as if in amber. The basic tasks of “clearing” the wheatbelt — particularly the regimes of annual burning and cutting — are remembered with particular pride by Facey.

Born a generation and a half later, Hewett grew up in a farm that was already in place. Although she left Lambton Downs (as it was dubbed) at the age of 11, Hewett’s writing returned again and again to the wheatbelt. Hewett’s wheatbelt had a mythic, gothic flavour in which the dream of it is present but often in inverted form. This wheatbelt is beset by a pernicious fatality and mired in the sexual miseries of her extended family.

Hewett deserves credit for being the first writer to take seriously the fact that the wheatbelt was built on land whose traditional owners had not disappeared but were still there, either impoverished in fringe-camps or incarcerated in government or church institutions.

The other side of the farming frontier

But it was the emergence of Aboriginal writing in the generation politicized by the citizenship referendum that brought a powerful voice from the other side of the wheatbelt frontier. Jack Davis had spent time in the notorious Moore River Native Settlement on the edge of the mid-northern wheatbelt, and then (after the untimely death of his father), with relatives of his mother’s sister at the Brookton reserve in the Avon valley. There he did the usual itinerant work that Aboriginal families did in the wheatbelt’s early years — clearing, fencing, shearing, rabbiting.

What Davis gives us in his poetry of the 1970s and the great plays of the 80s is a completely alternative vision of the wheatbelt. It doesn’t look like wheatbelt literature for the simple reason that it does not proceed either positively or negatively from the wheatbelt dream. Instead, it proceeds from Aboriginal presence in the land.

The tragedy of the Noongar is shown in all its woeful extremity, but tempered by Davis’s astringent sense of humour—his black humour if you like. But really Jack Davis is writing about survival. His example has provided a platform for a writer like Kim Scott to foster new forms of Noongar creative re-emergence, and also new forms of penetrating critique.

At the same time that a consciousness of Aboriginal dispossession began to force its way into the understanding of the wheatbelt, a much sharper sense of its ecological cost was also starting to emerge. Certainly, right through my literary history of the wheatbelt there was a realization that the waving fields of wheat were planted on lands stripped of their native ecosystems.

Everyone knew this because everyone spent a considerable part of each year toiling to clear the land. But the view tended to be that there was always more bush. Each bit of clearing was a merely local matter. Likewise, as rising salinity became directly associated with the clearing of native perennial vegetation, it was repeatedly explained away as a small, local, confined phenomenon.

Environmental destruction

But in the writing of Peter Cowan and that of the naturalist, Barbara York Main, the full picture of environmental destruction began to appear without the customary euphemism. It would be wrong to say that public opinion, particularly in the wheatbelt, changed decisively in the 1960s or even the 1970s. The cart-blanche denial, however, of environmental value — that the natural world of the wheatbelt had a value — became harder and harder to maintain.

By the 1980s, the wheatbelt had become uncanny. No longer the sign of the natural cycles of life replenishing the earth with seasonal regularity, but a vast and even repellent monocultural expanse. The wheatbelt was something profoundly unnatural in the eyes of writers like Elizabeth Jolley, Tom Flood and John Kinsella.

Of these, it has been Kinsella who has proved to be both durable and prolific. His poems, stories and other writings specify a wheatbelt that exists in strange cross-currents of science, tradition and avarice. The natural world is prised out of its familiar romantic categories and, in his remarkable work, exists in eerie counterpoise to the techno-scientific mania of modern agribusiness.

The central fact of the wheatbelt is radical disappearance. On one hand there was the destruction of the sovereign culture of the Noongar, custodians for millennia. Noongar people continue to practice and uphold their culture in spite of everything and the land continues to speak through them.

But on the other hand we must also contend with the fact that in the central wheatbelt shires, at least, only something like 7% of the natural vegetation (and the animal habitat it provides) remains. This, in a place that has a biodiversity as stunning as a rainforest canopy.

Charred timber after the ‘burn’.
State Library of Western Australia

Literature cannot, in and of itself, make these losses good. A thousand novels cannot replace one extinct species. But in human terms there is hope. The Noongar language is being revitalized. And here literature certainly does have a role to play. Jack Davis used Noongar in his plays and provided his own glossaries. Kim Scott’s fiction, and occasional poetry, gives its readers Noongar — in fact teaches its readers Noongar and the deft sonics of a language adapted to country. And many of today’s farmers are now at the forefront of conservation initiative and Landcare groups.

The role, though, that I see for literature in coming to terms with the facts of the wheatbelt lies in its capacity to continuously disabuse us of the complacent certitudes by which we think we know the world. It need not require the experimental bravura of Kinsella’s postmodern verse to do this unsettling. Even the older writing does it in surprising ways.

Only 7% of the central wheatbelt’s natural vegetation is left.
Google Earth.

What Dorothy Hewett and Jack Davis do within the broad parameters of theatrical realism nevertheless succeeds in unpicking the simple pouches we tend to pack our conceptions in. Barbara York Main’s natural histories throw open the dazzling singularity of wheatbelt life forms, and at the same time their intricate interconnections. Peter Cowan’s quietist studies of disillusioned loneliness, defamiliarises the wheatbelt just as certainly as Facey’s childhood glee at burning the bush to smouldering ashes.

It is not a particular kind of literature that gets to the “heart” of the wheatbelt. It is the fact that the wheatbelt falls into the prism of literature that allows us to see this place in terms other than the ones it gave itself via its animating dream of agricultural plenitude and generational continuity.

Creative writing is not blind to the natural or economic forces that determine the fate of the wheatbelt, but it will always approach the matter through the medium of human subjectivity. In this sense, it is only literature that allows us to see inside the wheatbelt that was created, geologically speaking, in the blink of an eye.

Tony Hughes-D’Aeth, Associate Professor, English and Cultural Studies, University of Western Australia

This article was originally published on The Conversation. Read the original article.