The Canberra fires of 2003: a pine planataion on the edge of the Brindebella Ranges ignites
Credit: SMH
By midday on that hot, summer Saturday in Canberra, smoke from the largest bushfires in the history of the surrounding Australian Capital Territory had eclipsed the Sun. Firefighters were battling flames along a 35 km front.
It was 18 January 2003, and few people were overly concerned. Summer is, after all, fire season in the bush, and Canberra, in the southeastern inland of the country, is often called the bush capital. Bushfires are as much a part of Australia's summer as barbecues and Christmas holidays on the beach.
Although low-intensity fires fed by grass and scrub had been steadily advancing on Canberra's sprawling outer suburbs over the years, they seemed to pose little danger to life, limb or property.
But a two-year drought had primed the region around the nation's capital for something bigger. At about 1.30 in the afternoon, wind-fanned flames leapt to the tops of the native eucalypts and imported pines, igniting them. From there, the fires virtually exploded.
Modest ground fires became high-intensity blazes with temperatures exceeding 1,000°C - almost hot enough to melt copper. Eyewitnesses described plasma-like balls of fire detaching from the fire front and blowing forward to ignite everything in their paths. Flames towered 30 metres above the trees, and the wildfire grew so hot that it generated a wind that reached 240 km/h. Cars and trailers were blown around. Trees more than a metre in diameter were uprooted and hurled atop houses, and full-grown pines were snapped in half.
Fire crews had no time to evacuate. The firefighters huddled beneath their vehicles while fire-induced winds blew in windshields and tore off doors. John Ryan, a commander of the New South Wales Rural Fire Service, later told Adelaide's The Advertiser newspaper: "There were birds falling out of the sky as we were overrun by the firestorm." Some firefighters reported that wild animals whose fur was smouldering also hid beneath the trucks, their fear of the fire outweighing their fear of humans.
Describing the scene later, Peter Roth, Ryan's deputy, told reporters, "It was more like a fire hurricane than a firestorm". He added, "I said to the chief, 'If we don't see you again, it's been nice knowing you' ".
Roth and Ryan survived, but others were not so lucky. The fires ultimately killed four people, destroyed more than 500 homes, and reduced nearly two-thirds of the Australian Capital Territory to ash. The losses included the Australian National University's giant optical telescopes at the Mount Stromlo Observatory, just west of Canberra - completely destroyed, their metal domes and telescope mountings melted.
As with many natural disasters, the fires were capricious. Farther outside town than Mount Stromlo, flames stopped just metres from the radio dishes of NASA's Deep Space Communications Complex at nearby Tidbinbilla, vital for maintaining contact with dozens of spacecraft, including the Mars rovers, Spirit and Opportunity.
Losing the complex would have been a serious setback for the U.S. space agency, potentially causing a communications blackout for eight hours a day. Yet even as they spared the NASA site, the fires burned more than 99 per cent of the 55 km2 Tidbinbilla Nature Reserve, just 5 km away. The reserve was also home to dozens of koalas, only one of which, although horribly burned, survived.
The fires of 2003, and the ones that struck the Eyre Peninsula of South Australia in January 2005, where nine people died and some 800 km2 of bush was incinerated - were not totally unexpected; much of Australia is hot and dry, and the continent has been like this for millennia.
But Australia may be becoming even hotter and drier and, by all historical comparisons, the intensity of the recent fires is epic. A deep drought has continued for the past decade. Dams serving the city of Canberra and nearby areas have been as low as 35 per cent full. Canberra has recovered steadily since the fire of 2003, but every Australian knows the risk of devastating fires each summer remains high.
A number of climate experts have begun to ask whether the current drought and the recent fire seasons, which have been considered exceptional, are actually the new commonplace.
Answering that question requires consideration of familiar global atmospheric phenomena. The weather system known as El Niño, for instance, has had major effects on Australia's climate for thousands of years. The effects of global warming, atmospheric pollution, and water shortages - for which humanity may bear substantial responsibility - must also be factored in. And even if climatologists can sort out the causes of Australia's suffering, can anything be done to reverse their effects? The answers are not necessarily encouraging.
Conditions in Australia today seem unlike anything on record. Early written accounts, archaeological data, tree rings, cores of ocean sediments, and other indicators are all beginning to paint a picture of the history and prehistory of Australia's climate.
According to David A. Jones, a climatologist at the Bureau of Meteorology in Melbourne, Australia's climate is rapidly warming, and the warming trend is compounding the drought. Another climatologist, Timothy P. Barnett of the Scripps Institution of Oceanography in San Diego, California, agrees. He points out that the centre of Australia - what Australians love to call the 'red centre' - appears to be getting hotter and drier more quickly than the edges of the continent. Such preferential heating, he says, is evidence of a prolonged, permanent climate shift.
And it's not just Australia. Droughts are becoming distressingly common across many of the world's less-watered regions. New research shows that the percentage of the Earth's land area undergoing serious drought has doubled in the past 30 years, according to data presented at a meeting of the American Meteorological Society in January 2005. Aiguo Dai and his colleagues of the U.S. National Centre for Atmospheric Research in Boulder, Colorado, said that almost half the change is due to rising temperatures rather than decreases in rainfall or snowfall. "Global climate models predict increased drying over most land areas during their warm season, as carbon dioxide and other greenhouse gases increase," Dai told reporters. "Our analyses suggest that this drying may have already begun."
Climate experts at the U.S. National Oceanic and Atmospheric Administration envision such a preponderance of prolonged, severe, geographically wide-ranging events in the future that they have coined the term 'mega-drought' to describe them.
From his studies of historical climate patterns recorded in tree rings, Thomas W. Swetnam of the University of Arizona in Tucson - a former firefighter with the U.S. Forest Service - sees a clear link between the worst droughts and the worst fire years. And there are good reasons to think that El Niño, a big factor in Australia's droughts, is becoming more powerful.
For three or four years out of five, on average, ocean temperatures stray very little from their mean. But in that fifth year - the interval itself is a rough one - the sea surface and atmosphere in the tropical regions of the western Pacific Ocean warm dramatically. The warm water and air masses move eastward across the equatorial region, until they reach the west coast of the Americas.
Because it arrives around Christmas, the warm currents and air masses are known as El Niño, literally 'the [Christ] child'. El Niños usually last between one and two years, and cause wet conditions off Peru and in the U.S. southwest. In Australia, an El Niño causes drought, as high-pressure cells, or air masses, develop over the northern half of Australia and create persistent warm, dry conditions.
After an interval of three to seven years, an opposite phenomenon, dubbed La Niña, 'the girl', takes hold, which lasts a similar length of time to El Niño. In La Niña years, Australia becomes wetter.
The cycling between the two extremes encourages the evolution of fire-dominated ecosystems. In wet years, grasses, trees and other vegetation grow abundantly, producing large amounts of fuel to burn during dry periods. The ashes from the fires serve as fertiliser for a new round of explosive growth during the next wet phase.
The precise mechanism driving an El Niño year is complex and still not fully understood, and the cycles are not entirely predictable. But in the late 1980s Neville Nicholls, a climatologist at Australia's Bureau of Meteorology, pointed out that the pressure difference between highs over Darwin, in the Northern Territory, and lows over the island of Tahiti has been a good historical indicator of whether an El Niño was either underway or about to begin.
That difference, Nicholls suggested, could serve to forecast future Australian droughts; the more negative the index, the greater the likelihood of a drought. Now known as the Southern Oscillation Index, it has become so widely accepted that it is misused for short-term forecasting: the index is often part of television weather reports.
Climatologists are still seeking the answers to two big questions. Firstly, what drives the frequency of the switches from hot, dry El Niño years to moist La Niña ones over the centuries? And secondly, what causes the varying intensities of the events? Longer cycles, in which one or the other extreme predominates, apparently exist; explaining those would go a long way to predicting whether, say, one wet year after a five-year drought signals only temporary relief or marks the beginning of multi-year wet period.
There is, of course, a third question. Why are the extremes becoming more extreme? Why are the wet phases becoming wetter, and the warmer phases becoming drier and more beset by fire? Global warming seems a prime suspect. "Among scientists, there's no real question about whether global warming exists," says Barnett. "The only questions are more a matter of how much and how fast, and what its specific impacts are in a given area.
The debate about global warming is over, at least among rational people."
According to the Intergovernmental Panel on Climate Change - a respected group of leading scientists established by the World Meteorological Organisation and the United Nations Environment Program - the past decade included five of the hottest years since accurate meteorological records began to be kept in the 19th century.
Worldwide, September 2005 was the warmest month on record, according to the U.S. National Oceanic and Atmospheric Administration. And 2005 will be the second or third warmest year on record globally, Britain's national weather service said in October.
"Whether it is second or third depends on how Siberia reacts between now and the end of the year," said Wayne Elliott, a spokesman the Met Office. "1998 was the warmest ever, 2005 is looking at being second. It will be another very warm year generally, which is in line with global climate-change research."
Based on British measurements of temperatures on land and sea going back to 1861, the world's second hottest year was 2002, followed by 2003, 2004 and 2001. It's not merely a scientific curiosity: this year, Portugal and Spain have experienced their worst droughts ever as well as crippling wildfires; while further east, floods and torrential rain drenched Switzerland, Germany, Austria, Bulgaria and Romania. It's more evidence that global warming is caused, at least in part, by human activities.
The story by now is a familiar one, but it is no less urgent for that. When certain gases - carbon dioxide, water vapour, methane, chlorofluorocarbons, and others - are released into the atmosphere, they act like the glass panes of a greenhouse. Visible light can pass through them, but radiant heat from the Earth's surface cannot flow back as readily into space.
Since the Industrial Revolution, the greenhouse gases in the atmosphere have had their heat-retaining properties enhanced by a 30 per cent increase in atmospheric carbon dioxide. Carbon dioxide levels are now higher than they have been at any other time in the past 420,000 years. The resultant warming is thought to be a factor in the further desiccation of areas that are already dry.
Australia's normal climate variability makes it difficult to be specific about which effects are attributable to global warming - not that theses are easily itemised even in far less complicated systems. Global warming, despite its name, is not merely a uniform rise in global temperature. The retained heat can lead to quite paradoxical outcomes. Some global-warming models, for instance, predict a massive cooling in northern Europe, as changes in the salinity of Atlantic sea water - resulting from the melting of polar ice - shut down the Gulf Stream.
An additional, complicating factor in the case of Australia is the effect of aerosols - fine droplets of water, or particles of dust, soot, pollen, and the like, which can remain suspended in the atmosphere for weeks at a time or longer. Beate G. Liepert, a climatologist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, studied the effects of atmospheric aerosols in combination with global warming.
With a computer model developed by Johann Feichter and Erich Roeckner at the Max Planck Institute for Meteorology in Hamburg, Germany, and Ulrike Lohmann of the Swiss Federal Institute of Technology in Zurich, Liepert found that atmospheric aerosols make Australia drier. Aerosols, like greenhouse gases, contribute to global warming. The warmer the atmosphere, the more water it can hold. And in general, if water is locked up in the atmosphere, global rainfall is reduced, including the rainfall over Australia. So as El Niño brings dry times, aerosols make Australia's climate even drier.
Intriguingly, Liepert discovered that the effects of aerosols, like those of global warming, are uneven: they do not weaken India's monsoon system, for instance. In fact, she predicts the combined effect of greenhouse gases and more aerosols in the atmosphere would make the Indian monsoon wetter, even as it makes Australia drier.
In spite of such progress in understanding the system, much work remains to be done. "We've only known about El Niño for the past 20 years," says Swetnam, "and only better understood it in the past 10." And, he adds, there are other weather cycles that climatologists are only beginning to recognise.
For example, some researchers believe the frequency and strength of El Niño and La Niña episodes are influenced by something called the Pacific Decadal Oscillation (PDO), which occurs in the North Pacific Ocean. Unlike the tropical Pacific's El Niños and La Niñas, which last for relatively short periods, PDO's two alternatives - 'positive' and 'negative' - each last 20 to 30 years.
During a positive PDO, the waters in the central north Pacific are cool, and the waters along the west coast of North America are warm. The converse is true with the negative phase. During the past century, PDO was in its positive phase from 1925 to 1946 and again from 1977 to 1997. The frequency of El Niño episodes increased during the later period and two of the strongest El Niño episodes on record occurred in 1982-83 and 1997-98.
However David Jones also emphasises the uncertainties. No one knows, he says, whether 90 per cent or 10 per cent of the changes in rainfall are the result of human-induced climate change. Yet he says, "It is now fairly clear that the current large and complex patterns of climate change are the result of aerosol changes, ozone change and greenhouse-gas changes, with a component of natural variability thrown in for good measure".
Whether or not humanity in general is exacerbating global warming and thus intensifying the droughts that plague the Australian continent - the driest after Antarctica - it's clear Australians themselves are contributing to their water shortage. The country's most economically important river system, the Murray-Darling, which drains much of Queensland and New South Wales, is drier now than it has been at any time in recorded history, its feeble flow the result of drought and voluminous withdrawals for farms, cities and reservoirs.
Some Australians further narrow the culprit to 'Big Irrigation': three water-intensive crops - cotton, rice and sugar - together account for about a third of the country's agricultural water consumption. The Murray-Darling basin's rice farms collectively use almost as much water as all of Australia's 20 million people, and some argue that Australian farmers should grow less thirsty produce. At any rate, tying up more and more water in water-intensive agriculture makes the rest of the place drier and more prone to burning.
But are global warming, increased drought, and recent human activity really the most important factors in making Australia increasingly prone to fire? Some ecologists have argued, on the contrary, that Australia is fire-prone chiefly because Australia's Aborigines made it so. In books such as The Future Eaters by moted biologist Tim Flannery, former director of the South Australian Museum in Adelaide, and The Burning Bush by Stephen Pyne, an environmental historian at Arizona State University in Tempe, USA, the idea is advanced that Aboriginal practices in place for tens of thousands of years were what really transformed the land into a fire-dependent ecosystem.
According to the hypothesis, Aborigines practised relentless, widespread burning in Australia for millennia - to drive game, clear land, forge pathways, and encourage new growth. The frequent burning would have eliminated shade-loving plants and favoured fire-loving, Sun-worshiping eucalypts.
The latter have developed specialised, enlarged woody growths called lignotubers, which can store nutrients and water in the earth, out of the reach of fire. If a tree is destroyed by fire, the lignotubers can send up new shoots almost immediately. In addition, the layered bark of the eucalypt forms a protective shield, which burns off in successive layers like the heat shield of a spaceship on re-entry. So, the argument goes, over many aeons, a self-reinforcing, dynamic process emerged: people burned the land, eucalypts thrived, people burned some more.
The hypothesis has two major practical implications for today's Australia: modern agriculture, by eliminating fire from its toolbox, has inadvertently increased the risk of massive fires by allowing fuel to accumulate through the years. Thus, to reduce the risk of large fires, smaller ones should frequently be set.
In favour of the hypothesis, some Aborigines are known to have practised "fire-stick farming" in some regions - purposeful, periodic clearing of large areas to manipulate the land for their own purposes. But opponents of the hypothesis counter that ascribing the evolution of a fire-prone ecology solely to the hand of fire-wielding humans is too simplistic.
Re-examining the early written records of the first European explorers in Australia, Rod J. Fensham of the Queensland Herbarium in Toowong found that although Aboriginal burning was prevalent along Queensland's coast, it was infrequent inland. Most of the early accounts of Aboriginal fire use, moreover, were written during a tumultuous era. Aborigines were losing their land, becoming exposed to new diseases, and running into conflicts with Europeans. The fires the explorers saw may not have been set to manage the land, but rather to protect Aborigines from European intruders, or perhaps signal the newcomers' presence to others.
Recently Scott Mooney, a palaeoecologist at the University of New South Wales in Sydney, studied charcoal in lake sediments at Jibbon Lagoon in the Royal National Park, just south of the city. He showed that concentrations of charcoal were lower before the arrival of Europeans in Australia, in 1788, than they were afterward.
Furthermore, Mooney found, the number of fires increased dramatically after 1930. He asserts his evidence proves that Aboriginal people did not conduct regular burns in the land now encompassed by the park. In addition he notes that his studies in the nearby Blue Mountains have shown links over the past 14,000 years between fires and previous episodes of climate change; the Aboriginal contribution the fires was marginal.
The problem with many popular accounts, Mooney contends, is that they simplistically assume that all Aborigines lived the same kinds of lives. "The last Aboriginal people to live traditional lifestyles," he notes, "lived in desert communities in Western Australia and the Northern Territory, and they did use fire. But to apply this to all landscapes and to all Aboriginal groups in Australia is ridiculous."
In a final twist, Neville Nicholls turns the argument that Aboriginal practices created a fire-prone Australia on its head. In a 2002 paper, Nicholls suggested that Australia's highly variable, drastic climate swings may have made permanent agriculture less attractive to Australia's hunter-gatherers. Rather than changing the landscape with fire to suit their needs, the Aborigines, Nicholls argues, were forced to remain hunter-gatherers by their climate's drastic swings and the fires it caused.
If so, then even today climate change is far more important in regulating the frequency and intensity of wildfires than people are. Setting regular, low-intensity ground fires can burn off excess fuel and diminish the frequency of explosive fires. Such fire-management practices certainly may help save individual homes, sheep stations, and businesses. But fire management alone cannot address Australia's long-term bushfire problems, for the simple reason that such burns can do nothing to ameliorate the climate.
If the hot, dry, fire-prone climate of Australia moulded the lifestyle and behaviour of Aborigines, then modern Australians, too, may have to adopt a lifestyle more in keeping with a hot, dry ecosystem. That means growing crops that are less water intensive and developing technologies that consume less water and produce less greenhouse gas. People may have to rely on rooftop water-collecting tanks, which were once common in the outback. In place of air conditioners, they may have to use shaded porches; in place of fossil fuels, solar panels; in place of lush English gardens, plants suited to a dry environment.
The more arid regions of the United States, and many countries, including Portugal and Spain, may be glimpsing a part of their own future in Australia, a future in which water restrictions, drought, and more intense, longer-lasting, and deadlier fire seasons become a way of life.
Governments would be prudent to start planning now for worst-case scenarios, especially in areas settled in wetter times: where water was once plentiful, it may become scarcer.
How 20 million people on the world's largest island and driest liveable continent cope with changes to their environment could well be a harbinger for what is to come elsewhere. It will either be a success story for the rest of the world to emulate, or a cautionary tale to warn others. "We're in the hottest decades in history," Thomas Swetnam declares. "It's gonna get warmer, it's gonna burn better and we're gonna see more fires."
Dan Drollette is a science writer and photographer in New York who fell in love with Australia on his first visit on a Fulbright fellowship in 1995.
