Eyes on Earth Episode 27 - Australian Wildfires
The continent of Australia experienced some of the most devastating wildfires in its history in late 2019 and early 2020. Remote sensing scientists in Australia, who collaborate closely with EROS, relied on satellites like Landsat to help assess and monitor the damage. In this episode of Eyes on Earth, we hear from one of our Australian partners on the value of satellite imagery before, during, and after a wildfire, and we explore how cross-hemisphere partnerships improve our understanding of disasters around the globe.
Hello everyone. Welcome to this episode of Eyes on Earth. Our podcast focuses on our ever-changing planet, and on the people here at EROS and across the globe who use remote sensing to monitor and study the health of Earth. Iím your host, Steve Young.
Australiaís historic fires, the Black Summer fire, raged from September 2019 into February of 2020, and werenít fully extinguished until this past March.
According to government and media reports, the fires were estimated to have burned 18.6 million hectares, or 46 million acres. In comparison, the 2018 California wildfires consumed 2 million acres. The 2019 Amazon rainforest wildfires burned 2.2 million acres of land.
The numbers reported in the media on the impact in Australia are staggering: 5,900 buildings, including 2,779 homes were destroyed. Thirty-four people died. An estimated 1 billion animals were killed, driving some endangered species to the brink of extinction. According to the Global Fire Emissions Database, funded in part by NASA, the fires emitted an estimated 400 million tons of carbon dioxide into the atmosphere, pushing country-level estimates for all of 2019 in Australia to a satellite-era record of 900 million tons of carbon dioxide.
Joining us today to talk about this incredible and historic event, and the role that Earth-observing systems like Landsat played in helping Australia deal with those fires, is Simon Oliver. Mr. Oliver is the National Earth and Marine Observations (NEMO) Director of Operations and Production for Geoscience Australia, which is Australia's pre-eminent public sector geoscience organization.
Also with us is Steve Labahn, the Landsat International Ground Station Network Manager for the U.S. Geological Survey.
So, letís start with you, Steve. Tell us about this longstanding connection between the USGS and Geoscience Australia that ended up with Landsat and other Earth-observing platforms being so helpful during Australiaís recent fires.
So, since about 1979, the USGS has been working with Geoscience Australia. They operate a ground station in central Australia in a city called Alice Springs. That ground station is part of our global Landsat International Cooperator Network. And Geoscience Australia has really been instrumental in exhibiting leadership across our entire network of providing vital ground station services for, currently, operational Landsat 7 and 8 missions today, as well as looking to the future with Landsat 9. And, having this ground station has enabled data acquisition and product generation in near real time over Australia, which has greatly assisted the response to these natural disasters, such as these fires.
Simon, give us a perspective on the magnitude of these fires, at least as they compare to previous wildfires in your country.
As youíve mentioned, Steve, these fires were extraordinary on a number of fronts ñ particularly with respect to the massive amount of country burnt, the impacts on wildlife, and the persistent and wide-spread hazardous air quality that affected people across the southern parts of Australia over a number of months. Australiaís worst bushfire on record, at least in terms of loss of life, occurred on the seventh of February in 2009 in the state of Victoria in the countryís southeast. This fire is commonly referred to as the Black Saturday bushfire and claimed 173 lives, compared to the 34 lives lost in the recent fires. Black Saturday also destroyed around 2,000 homes compared to the 2,800 homes in the most recent fires. The 2009 fires burnt through around half a million hectares of country. In comparison, the recent fires burnt through 18.6 million hectares, so around 40 times more than in 2009. The Bushfires Royal Commission which the government set up in the aftermath of the Black Saturday fires, determined a total cost of around $4.4 billion for that event. Estimates of costs from most the recent fires are expected to exceed that number. So, in terms of the magnitude of the recent fires, they claimed fewer lives than the earlier Black Saturday fires, but burnt out a much, much larger area and had far more significant and widespread impact on wildlife. Extremely hot, dry conditions, underpinned by years of reduced rainfall and a severe drought, really set the scene for this summerís unprecedented fires.
I referred earlier to a satellite-era record of 900 million tons of carbon dioxide estimated to have been emitted into the atmosphere in Australia in all of 2019. How do satellites help to measure that?
So, broadly speaking, there are two approaches. Direct methods, which look at the atmospheric chemistry and quantify atmospheric concentration of greenhouse gases such as carbon dioxide and methane. And then there are indirect methods, such as estimating ground conditions like vegetation type, fuel loads, area burnt, and fire intensity information from satellite sensor data such as that provided by Landsat 8 or Sentinel-2, and feeding that information into an ecosystem model to quantify emissions. Australia uses satellite data for carbon accounting using a quite advanced ecosystem model known as FullCAM, or the Full Carbon Accounting Model. The model requires inputs from quite a few spatial datasets, but most important in this is the land cover change data derived from Landsat time series data from 1972 onwards.
I understand that satellite data can be extremely helpful in assessing fuel loads in forests, as well as informing forest managers as they consider such things as prescribed burns to mitigate the extent of future wildfires? Is or has Australia done this?
Yes, in fact, several universities are working on this issue, in conjunction with the emergency services, to provide information of this kind. To date there is an operational grassland curing product, which uses NASAís MODIS data, and this is routinely delivered through the Australian Bureau of Meteorology. This product provides information on grassland fuel dryness and hence its volatility. In addition, new services are becoming available from the Australian National University using MODIS to provide fuel moisture more generally, which in turn informs fuel volatility. At Geoscience Australia we are currently investigating the implementation of this particular product using Sentinel-2 satellite data.
Do you get what you need from existing Earth-observing systems, or do you see a point where Australia would launch its own satellite, in particular to monitor the countryís landscapes?
Well, the need for Australian missions has not been decided by government, but the Australian National University has been in the news lately regarding their bushfire monitoring satellite development. It will be exciting to see this progress. Australia has very strong data integration and analysis capabilities and makes great use of existing systems such as Landsat, and there are always improvement programs underway. However, the examination of the use of Earth observing satellite data for bushfire risk mitigation has shown that there is definitely an appetite for more frequent revisit, higher resolution, faster and more reliable data deliveryóall of which could be improved by Australian missions. Hypothetically, an Australian mission could take many forms, from wholly Australian to a contribution to another nationís program. Whatever form it might take, Australia would be intent on ensuring it fits into the global operational Earth observation system, to make a meaningful upstream contribution back to those nations that have supported Australia for so long.
Can you use Earth-observing data to assist in air quality forecasts? And if so, how were those forecasts used?
Air quality isnít typically of concern to Australians, but the bushfires changed that somewhat. In particular, ground-based air quality monitoring stations were used to great effect to notify the populations of hazardous conditions, especially with respect to particulate pollution, and to enable residents to take precautionary measures. In Sydney, the city's air quality exceeded ëhazardousí levels on numerous occasions. Many households purchased air purifiers, kept their houses sealed, and were advised by authorities to minimize outdoor activity. Weather forecasters in Australia utilize Earth observation data as a key input to their modeling and prediction. In combination with ground based and satellite-based aerosol detection, authorities were able to provide forecasts of smoke movement.
What happens as far as carbon sequestration goes after so much forest is lost? Does satellite information help inform that conversation?
Yes it does. Landsat data is used to monitor post-fire regrowth by the National Inventory Team here in Australia. Theyíve done detailed modeling of emissions from the recent bushfires and will be publishing a factsheet on that very soon. Landsat and other satellite data sources are used to study decadal trends in vegetation around the globe to support modeling of carbon fluxes to the atmosphere. Australiaís National Inventory Team, for example, pioneered this effort in the last two decades by putting together a record of forest-cover changes from thousands of individual Landsat scenes from 1972 onwards. The changes in forest area determined through these studies can then be used to model changes in biomass using the FullCAM model, which predicts the growth of individual forest stands for instance.
How will Landsat and other Earth-observing systems be used to help Australia recover from this disaster?
Landsat, in particular, is an invaluable resources to enable our understanding of vegetation dynamics and the environment in general in Australia. Weíll make use of the long-term archive to measure the current state, compare with earlier years and then track recovery into the future. We use a number of products created by Australian universities in this way, especially to monitor changes in land cover and vegetation canopy cover. These will be essential going forward, to be able to understand the impact of the fires and then monitor the recovery of the environment
Weíve been talking to Simon OLIVER, the National Earth and Marine Operations Director of Operations and Production for Geoscience Australia, about his countryís historic wildfire season. Also joining us for the conversation has been Steve LABAHN, the Landsat International Ground Station Network Manager for the USGS.
We hope you come back for the next episode of Eyes on Earth. This podcast is a product of the U.S. Geological Survey, Department of the Interior. Thanks for joining us.