Recent Australian droughts may be the worst in 800 years



File 20180403 189798 1g87upm.jpg?ixlib=rb 1.1
Places such as Berri were affected by Millennium Drought, caused by low cool-season rain. New materials and techniques are now being used to observe drought causes and water patterns in Australia’s history to help the future.
Gary Sauer-Thompson/flickr, CC BY-NC

Mandy Freund, University of Melbourne; Ben Henley, University of Melbourne; Kathryn Allen, University of Melbourne, and Patrick Baker, University of Melbourne

Australia is a continent defined by extremes, and recent decades have seen some extraordinary climate events. But droughts, floods, heatwaves, and fires have battered Australia for millennia. Are recent extreme events really worse than those in the past?

In a recent paper, we reconstructed 800 years of seasonal rainfall patterns across the Australian continent. Our new records show that parts of Northern Australia are wetter than ever before, and that major droughts of the late 20th and early 21st centuries in southern Australia are likely without precedent over the past 400 years.




Read more:
Antarctic ice shows Australia’s drought and flood risk is worse than thought


This new knowledge gives us a clearer understanding of how droughts and flooding rains may be changing in the context of a rapidly warming world.

A history of drought

Australia has been shaped by floods, droughts, and blistering heat. How big and how intense these events were is poorly understood due to the limited historical and observational records.

Historical records provide rough estimates of the extent and intensity of droughts in parts of Australia since the late 1700s. For example, captains’ logbooks from ships anchored off of Sydney describe the Settlement Drought (1790-1793), which threatened the tenuous foothold of early European settlers in Australia. And farmers’ records describe the Goyder Line Drought (1861–1866) that occurred in areas north of the known arable lands of South Australia.

Observational weather records provide more detailed descriptions of climatic variability. However, systematic recording of weather in Australia only began in the late 19th century. Since then many parts of the continent have experienced prolonged wet periods and droughts. The most well known of these are the Federation drought (1895-1903), the World War II drought (1939-45), and the recent Millennium drought (1997-2009).

All three droughts were devastating to agriculture and the broader economy, but each was distinct in its spatial footprint, duration, and intensity. Importantly, these droughts also differed in seasonality.

Recent and historical droughts in Australia for the different natural resource management (NRM) regions.
Provided by M.Freund

For example, the Millennium drought, which was most severe in southwestern and southeastern Australia, was caused by poor rainfall during the cool season. In contrast, the Federation drought, which affected almost the entire continent, was predominantly due to rainfall declines during the warm season.

Although the historical and observational records provide a wealth of information about the frequency of wet and dry extremes, they provide only part of the picture.

Lancelot that became a ghost town following the Federation Drought.
denisben/flickr, CC BY-ND

Looking back

To understand possible trends in rainfall and assess the likelihood of prolonged droughts, we need to understand the long-term climatic context. For this, we need records that are much longer than existing observational and historical records.

Our new study used an extensive network of tree rings, ice cores, corals, and sediment records from across Australia and the adjacent Indian and Pacific Oceans to extend rainfall records across all of the major regions of Australia by between 400 and 800 years. Importantly, we did this for two seasons, the cool (April–September) season and warm (October–March) season, over eight large natural resource management regions spanning the Australian continent. This allows us to place recent observations of rainfall variability into a much longer context across the entire continent for the first time.

Seasonal rainfall for the past 400 years

We found that recent shifts in rainfall variability are either unprecedented or very rare over the reconstructed period. The two most striking patterns were in tropical northern Australia, which as been unusually wet over the past century, and southern Australia, which has been unusually dry.

Our reconstructions also highlight differences between recent extreme drought events and those in earlier centuries. For example, the Millennium Drought was larger in area and longer than any other drought in southern Australia over the last 400 years.

Our reconstruction also shows that the most intense droughts described in the historical records – the Settlement Drought (1790-93), Sturt’s Drought (1809–30), and the Goyder Line Drought (1861–66) – were limited to specific regions. The Settlement Drought appears to have affected only Australia’s eastern regions, whereas the Goyder Line Drought, which occurred north of the northernmost limit of arable lands in Southern Australia, primarily impacted central Australia and the far north.




Read more:
Friday essay: recovering a narrative of place – stories in the time of climate change


These historical droughts varied widely in the area they covered, highlighting at a continental scale the spatial diversity of drought. This spatial variability has also recently been demonstrated for eastern Australia.

The ConversationOur multi-century rainfall reconstruction complements the recent Climate Change in Australia report on future climate. By providing a clearer window into climates of the past online, we can better see how extremes of rainfall may affect Australia in the future.

Mandy Freund, PhD student, University of Melbourne; Ben Henley, Research Fellow in Climate and Water Resources, University of Melbourne; Kathryn Allen, Academic, Ecosystem and Forest Sciences, University of Melbourne, and Patrick Baker, ARC Future Fellow and Professor of Silviculture and Forest Ecology, University of Melbourne

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

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Royal National Park – Honeymooner’s Track (2 April 2013)


This is a video that I have put together from some of the photos and videos I took on my recent trip to Royal National Park during my NSW South Coast Trip from the 2-7 April 2013. I’ll be posting more videos of the trip as I put them together.

Australia: Warrumbungle National Park – Life Returning


The link below is to an article and photo gallery that reports on the Warrumbungle National Park after the recent major bushfire that swept through the park.

For more visit:
http://www.australiangeographic.com.au/journal/bushfires-ravage-the-warrumbungles.htm

Nuclear Power: Mini Reactors a Possibility


Despite the nuclear problems in Japan following the recent earthquake and tsunami disaster there, consideration still needs to be given to nuclear power as a possible green energy source – certainly I believe that this technology warrants more investigation. The article below raises the possibility of mini-nuclear reactors as being a possible and safer answer to our energy needs.

For more visit:
http://www.good.is/post/small-modular-nuclear-plants-a-cheap-risk-free-solution/

 

Koalas: Trees the Key to Growing Populations


A recent report on Koala populations has concluded that more trees are the key to growing populations and spreading habitats. Hardly sounds surprising does it – the article is linked to below.

For more visit:
http://sydney.edu.au/news/84.html?newsstoryid=6826

 

Tasmania: Ocean Warming is Happening


According to a recent report ocean warming is happening off the east coast of Tasmania. The consequences of such warming includes the decline of important kelp forests, fish distribution and changes in fish habitats, and a growing population of destructive sea urchins.

For more visit:
http://www2.utas.edu.au/tools/recent-news/news/cascade-of-climate-change

 

Check In: Day 3 of Holiday


Today was spent chiefly at Dorrigo National Park, where I spent nearly 5 hours on a bushwalk through the wilderness surrounding the Never Never Picnic Area. This is a spectacular area within the Dorrigo National Park. I could quite easily have spent far more time there trekking up both Sassafras Creek and Rosewood Creek. These are some wild streams that cut there way through the heart of the national park. Given all of the recent rain in the region, they were truly at their best today.

The new camera got a work out today, but I am not completely sold on it – though as a camera for panoramic photos it is fantastic and well worth buying for that function alone. The photo I have included with this post is of Rosewood Creek directly above Coachwood Falls. It is a brilliant place and very wild indeed.

I did pick up several leeches throughout the day, with one attaching itself to me just below the left knee. It wasn’t found for some time and had a good feed and I a good bleed after it was removed. Several more were found in my socks but they weren’t able to force their way through.

I’ll be working on the various photos and videos over the next week or so and putting together various packages for the website, Flickr, YouTube, the Blog, etc. There are some really terrific photos and videos among them. Hopefully today’s shot will whet the appetite for the rest of them.