Open data shows lightning, not arson, was the likely cause of most Victorian bushfires last summer

Tracy Nearmy/AAP

Dianne Cook, Monash University

As last summer’s horrific bushfires raged, so too did debate about what caused them. Despite the prolonged drought and ever worsening climate change, some people sought to blame the fires largely on arson.

Federal Coalition MPs were among those pushing the arsonist claim. And on Twitter, a fierce hashtag war broke out: “#ClimateEmergency” vs “#ArsonEmergency”.

Fire authorities rejected the arson claims, saying most fires were thought to be caused by lightning.

We dug into open data resources to learn more about the causes of last summer’s bushfires in Victoria, and further test the arson claim. Our analysis suggests 82% of the fires can be attributed to lightning, 14% to accidents and 1% to burning off. Only 4% can be attributed to arson.

Lightning, not arson, caused most Victorian bushfires last summer.
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What we did

We started with hotspots data taken from the Himawari-8 satellite, which shows heat source locations over time and space, in almost real time. We omitted hotspots unlikely to be bushfires, and used a type of data mining called “spatiotemporal clustering” – where time dimension is introduced to geographic data – to estimate ignition time and location.

We supplemented this with data from other sources: temperature, moisture, rainfall, wind, sun exposure, fuel load, as well as distance to camp sites, roads and Country Fire Authority (CFA) stations.

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Read more:
Bushfires, bots and arson claims: Australia flung in the global disinformation spotlight

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Victoria’s Department of Environment, Land, Water and Planning (DELWP) holds historical data on bushfire ignition from 2000 to the 2018-19 summer. The forensic research required to determine fire cause is laborious, and remotely sensed data from satellites may be useful and more immediate.

By training our model on the historical data, we can more immediately predict causes of last summer’s fires detected from satellite data. (Note: even though we were analysing events in the past, we use the term “predict” because authorities have not released official data.)

DELWP’s data attributes 41% of fires to lightning, 17% to arson, 34% to accidents and 7% to hazard reduction or back burning which escaped containment lines (which our analysis refers to as burning off).

Causes of fires from 2000-2019. Lightning is most common cause. The number of fires is increasing, and this is mostly due to accidents.
Own work

To make predictions for the 2019-20 bushfires, we needed an accurate model for causes in the historical data. We trained the model to predict one of four causes – lightning, accident, arson, burning off – using a machine learning algorithm.

The model performed well on the historical data: 75% overall accuracy, 90% accurate on lightning, 78% for accidents, and 54% for arson (which was mostly confused with accident, as would make sense).

The most important contributors to distinguishing between lightning and arson (or accident) ignition were distance to CFA stations, roads and camp sites, and average wind speed.

As might be expected, smaller distances to CFA stations, roads and camp sites, and higher than average winds, meant the fire was most likely the result of arson or accident. In the case of longer distances, where bush would have been largely inaccessible to the public, lightning was predicted to be the cause.

Spatial distribution of causes of fires from 2000-2019, and predictions for 2019-2020 season.
Own work

What we found

Our model predicted that 82% of Victoria’s fires in the summer of 2019-2020 were due to lightning. Most fires were located in densely vegetated areas inaccessible by road – similar to the historical locations. (The percentage is double that in the historical data, though, probably because the satellite hotspot data can see fire ignitions in locations inaccessible to fire experts).

All fires in February 2020 were predicted to be due to lightning. Accident and arson were commonly predicted causes in March, and early in the season. Reassuringly, ignition due to burning off was predicted primarily in October 2019, prior to the fire restrictions.

Spatio-temporal distribution of cause predictions for 2019-2020 season. Reassuringly, fires due to burning off primarily occurred in October, prior to fire restrictions. February fires were all predicted to be due to lightning.
Own work

Quicker fire ignition information

Our analysis used open-data and open-source software, and could be applied to fires elsewhere in Australia.

This analysis shows how we can quickly predict causes of bushfires, using satellite data combined with other information. It could reduce the work of fire forensics teams, and provide more complete fire ignition data in future.

The code used for the analysis can be found here. Explore the historical fire data, predictions for 2019-2020 fires, and a fire risk map for Victoria using this app.

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This analysis is based on thesis research by Monash University Honours student Weihao Li. She was supervised by the author, and former Principal Inventive Scientist at AT&T Labs Research, Emily Dodwell. The Australian Centre of Excellence for Mathematical and Statistical Frontiers supported Emily’s travel to Australia to start this project. The full analysis is available here.

Dianne Cook, Professor of Business Analytics, Monash University

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

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The Northern Lights

Explainer: what causes algal blooms, and how we can stop them

Michele Burford, Griffith University

Outbreaks of algae have killed up to a million fish in the Murray Darling Basin over the last two weeks. The phenomena of “algae blooms”, when the population of algae in a river rapidly grows and dies, can be devastating to local wildlife, ecosystems and people. But what are algae blooms? What causes them, and can we prevent them?

Microscopic algae are fundamental to life on earth. These tiny plants provide the fuel that drives marine and freshwater foodwebs, and via photosynthesis, they gobble up carbon dioxide to help counteract emissions, and provide us with oxygen to breathe. Besides rivers, streams, lakes, estuaries and the coast, they can also be found in diverse environments such as snow, soil, and in corals.

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Are toxic algal blooms the new normal for Australia’s major rivers?

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But when humans channel agricultural run-off, sewerage and stormwater discharge into waterways, we dramatically increase the amount of nutrients such as nitrogen and phosphorus. This creates an imbalance, because some microscopic algae are supremely effective at mopping up nutrients and can grow very quickly, dividing up to once a day and quickly overtaking other species. The result is an algal bloom.

Cyanobacteria (blue-green algae) under a microscope.
Author provided

So why don’t we have algal blooms all the time? This is because algae don’t just require nutrients to grow. Like any plant, factors such as temperature and light availability are also important in determining how quickly algae grow and whether they form blooms. Blooms also need slow moving or still water to become established.

In Australia, our algal blooms are typically in freshwaters. The main group of algae responsible for this are known as blue-green algae, or more accurately, cyanobacteria. They regularly bloom in warmer weather in our reservoirs, lakes and slow flowing rivers. In 2016, for example, 1,700km of the Murray River was affected by an algal bloom.

There are many ways they impact the environment and economy. Some algal blooms are toxic, requiring expensive water treatment and – in extreme cases – shutdown of water supplies. This isn’t just a problem in Australia. In 2014, some 500,000 people in the US were left without drinking water due to a toxic algal bloom in Lake Erie.

The toxins can also affect domestic animals, such as dogs, when they drink contaminated water, and limit use of lakes and rivers for swimming, boating and fishing. Even when algal blooms are not toxic, they unbalance the food web, reducing the number of species of animals and plants.

They can also reduce oxygen levels at night, as they switch from photosynthesis (producing oxygen) during the day, to a process called respiration at night where they use oxygen. Low oxygen can stress and even kill fish and other animals if they cannot escape this.

At some point, algal blooms crash when conditions become unsuitable. The resulting dead algae break down, providing an ideal food source for bacteria. This is when waters can become smelly, often with a rotten egg smell. As the bacteria multiply, they suck the oxygen out of the water. At this point, oxygen levels become low both day and night.

If the area of low oxygen is extensive, such as a whole lake or many kilometres of a river system, fish and other animals may not be able to escape to more suitable oxygen levels, and major fish deaths typically occur.

In other areas of the world, algal blooms have caused such severe oxygen conditions that thousands of square kilometres of ocean around the world are now known as dead zones, where no animals can live. These vast dead zones are not something we ever want to see in Australia.

So what can be done about blooms?

There are a wide range of treatments that can be used to control blooms, for example, aerating the water, and adding clays and chemicals, but the catch is they are very expensive on a large scale.

Ideally, the problem should be tackled at the source. This means reducing nutrient loads to our waterways. There has already been progress on this in our cities where sewage treatment plants have been upgraded to reduce nutrient loads to waterways. But tackling nutrients coming from agriculture – erosion, fertilisers, animal waste – is much more challenging and expensive because of the vast areas involved. So this remains work in progress.

It’s also very difficult to predict when blooms will occur; despite being simple plants, algae have an amazing range of strategies to grow and survive. But as we learn more about their complexity our ability to model and predict blooms will improve. This is crucial to managing risks to water supplies and preventing major environmental effects, such as fish deaths.

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Read more:
Toxin linked to motor neuron disease found in Australian algal blooms

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Ultimately there are no quick fixes to algal blooms. Given the pressure we put on our waterways, they are here to stay. In fact they are likely to increase due to increasing temperatures and more extreme conditions, such as droughts. We know what we need to do to reduce the scale and likelihood of blooms: the challenge is devoting the resources to achieve it.

Michele Burford, Professor – Australian Rivers Institute, and Dean – Research Infrastructure, Griffith University

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

Asia: Dams to Cause Environmental Disaster – Mekong River

The link below is to an article reporting on the construction of some 78 dams along the Mekong River system in south-east Asia, raising major concerns for the health of the river system and its fish population.

For more visit:
http://www.scidev.net/en/agriculture-and-environment/news/dams-a-potential-catastrophe-for-mekong-fisheries.html

Chile – Patagonia: Wilderness Threatened by Massive Dam

The Patagonian wilderness is truly an amazing place. I have never been there, but have been fascinated by it for years. It captures my imagination and wonder anytime I see pictures or footage of it. Now I have discovered that this wilderness is under threat.

The article below reports on plans to construct a massive dam that has the potential to cause massive destruction of the Patagonian wilderness. It would seem that the planned dam is incredibly foolish and will destroy a large section of one of the world’s last remaining wild places.

For more visit:
http://www.washingtonpost.com/world/chile-favors-7-billion-hydroelectric-dams-on-remote-patagonian-rivers-despite-opposition/2011/05/09/AFcA2aaG_story.html

 

Climate Change: Further Evidence

Further evidence has emerged for climate change with King Crabs now moving into the warming waters of Antarctica. The appearance of these crabs in Antarctic waters is cause for real concern as they pose a serious threat to endemic species in this area.

For more on this story visit:
http://www.treehugger.com/files/2011/03/king-crabs-invade-antarctica-40-million-years.php

The Smithsonian Institute

The Smithsonian Institute is an important research center located in the United States. It consists of 19 museums, 9 research centres and the national zoo of the United States. It is extremely important in the international cause of conservation.

For more visit the website at:

http://www.si.edu/

The Fox Has Reached Tasmania

An investigation into possible fox populations in Tasmania has concluded that there are indeed foxes in Tasmania. It is thought that the fox population is currently small, yet the fact that the fox has now reached Tasmania is a major cause for concern. Some 24 plus native species will come under immediate pressure due to the fox now being active throughout the state. Evidence is now overwhelming that foxes are in Tasmania.

An eradication program will continue in its attempt to remove the growing fox problem in Tasmania.