How climate change influenced Australia’s unprecedented fires

fires

How climate change influenced Australia’s unprecedented fires

This piece originally appeared on Yale Climate Connections.

By Dana Nuccitelli

Australia’s frightening bushfires, which kicked off an early fire season in September 2019, have already had cataclysmic effects, and the continent is still just in the early months of the southern hemisphere’s summer. The New South Wales Rural Fire Service has described the bushfires as unprecedented in size and scale, having burned more than 46 million acres (18.6 million hectares), killed at least 29 people, and destroyed more than 2,200 homes.*

Parts of Australia have had the worst air quality in the world. The air quality in Sydney has literally been alarming, having set off smoke alarms in buildings throughout the city’s central business district and exceeded hazardous levels for more than 30 days. Military assets have been deployed in response to the fires at a scale not seen since World War II. Researchers estimate that more than a billion animals have been killed. Several species will likely be pushed to extinction.

The conditions and climate change-wildfire connections in Australia have been strikingly similar to those amplifying California’s record 2018 wildfire season, but on a much larger scale. Scientific unknowns remain regarding some of those connections, but others are a straightforward result of physics – more heat creates more wildfire fuel.

The politics and climate policy environment down under, on the other hand, more closely bring to mind those at the national level in the U.S. than to the situation in California.

How climate change exacerbated Australian and Californian fires

Despite widespread conspiracy theories about the bushfires, emerging science continues to find links between global warming and worsening wildfires, with the issue a focus of continuing investigation. As climate scientist Kevin Trenberth explained in a recent interview with videographer Peter Sinclair, global warming directly intensifies wildfires by drying out soil and vegetation, creating more fuel to burn farther and faster. That’s particularly a problem in drought-prone regions like Australia and California.

The Millennium drought in southeastern Australia from 1997 to 2009 was the driest 13-year period on record, according to a report by Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO). The drought was broken by Australia’s two wettest periods on record in 2010 and 2011, but then came yet another intense drought from 2017 to the present. In fact, 2018 and 2019 were Australia’s hottest and driest years on record. On December 18, the continent had its hottest day on record, with an average high temperature of 107.4 degrees F. California experienced a similar “weather whiplash,” swinging from record-breaking drought in 2012–2016 to a very wet rainy season in 2017–2018. That combination generated growth of new plants that were subsequently dried out by record heat, creating fuel for the state’s record 2018 wildfire season.

California’s drought was made worse by a persistent high-pressure system off the coast known as the “Ridiculously Resilient Ridge.” That high-pressure ridge diverted storm systems to California’s north, leading to years of low precipitation. Researchers have suggested that climate change may cause such blocking systems to form more frequently. A 2018 study led by UCLA’s Daniel Swain found that as temperatures continue to rise, California will see a shift to less precipitation in the spring and fall and more in the winter, lengthening the wildfire season.

The situation in Australia is again strikingly similar to that in California. Researchers have shown that global warming is expanding an atmospheric circulation pattern known as the Hadley cell. This circulation is caused by hot air at the equator rising and spreading toward the poles, where it begins to cool and descend, forming high pressure ridges. In Australia, this process creates what’s known as the subtropical ridge, which as CSIRO notes, has become more intense as a result of global warming expanding the Hadley cell circulation. A 2014 study, CSIRO’s David Post and colleagues reported that stronger high-pressure ridges have been decreasing rainfall in southeastern Australia in the autumn and winter. The significance? The lack of rainfall creates more dry fuel for fires and lengthens the bushfire season.

Based on this scientific research, the latest IPCC report found in 2014 that “fire weather is projected to increase in most of southern Australia,” with days experiencing very high and extreme fire danger increasing 5-100% by 2050. And a 2015 CSIRO report concluded, “Extreme fire weather days have increased at 24 out of 38 Australian sites from 1973-2010, due to warmer and drier conditions … [forest fire danger index] increase across southeast Australia is characterized by an extension of the fire season further into spring and autumn … partly driven by temperature increases that are attributable to climate change.”

Australia has among the world’s worst climate policies

According to the Climate Change Performance Index created by environmental groups, Australia is 56th out of 61 countries evaluated. In the category of climate policy, Australia comes in dead last with a score of zero because “experts observe that the newly elected government has continued to worsen performance at both national and international levels.”

In 2014, the Liberal Party (which, confusingly, is politically conservative by U.S. measures) became the first in the world to repeal a carbon tax. Echoing an approach taken by Oklahoma’s U.S. Senator James Inhofe on the floor of the Senate in 2015, Australia’s current Liberal Party Prime Minister Scott Morrison brought a lump of coal to the floor of the Australian House of Representatives in 2017. The country’s climate negotiators were accused of sabotaging the international climate agreement in Madrid in 2019, as they tried to use old “carry-over” carbon credits from the Kyoto Protocol to meet current climate goals.

Australia is the world’s leading exporter of coal and the second-largest producer and exporter of liquid natural gas, and the government recently proposed opening new coal mines and ports in what would be one of the world’s largest fossil fuel expansions. According to a recent report produced by the United Nations Environment Programme, Australia’s fossil fuel extraction-based emissions will nearly double from 2005 to 2030. In November, the Swedish central bank divested from Australian government bonds because of the country’s high emissions. Despite all this, as record bushfires continue to rage, Liberal Party leaders have maintained their position that Australia does not need stronger climate policies.

In short, as the country’s citizens and many visitors get a glimpse at its potentially dystopian future of worsening droughts and bushfires, its political leaders are doing everything they can to increase the fossil fuel extraction and combustion that experts conclude are exacerbating these extreme events. If the Paris climate goals are exceeded, the current record Australian temperatures will become the norm for the country. The public appears increasingly concerned: In a November Guardian Essential poll, 60% of Australian voters said the government should do more to reduce risks posed by the warming climate, and this concern has been clear in U.S. network and cable TV coverage of Australian citizens’ reactions to the fires. But Morrison and his Liberal party nonetheless prevailed in the last federal election in May 2019, and barring an early dissolution, they won’t face re-election until 2022.

Yale Climate Connections Editor’s note: These numbers on impacts of the bush fires increase regularly. A useful resource for keeping track of those changes can be found on this page.

Dana Nuccitelli is an Environmental Scientist who has written about climate change for The Guardian, Skeptical Science, and others. He is a member of CCL’s Economics Policy Network.

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