Burning Hot Issues Arise From Australia's Worst Drought

In Australia, the first drought where the influence of human-induced global warming may be discernable has just occurred. Hotter droughts mean more risks. Risks to fragile ecologies and human environments.

During 2002 and early 2003, Australia experienced arguably its worst drought since reliable records began in 1910. Over huge areas of the continent, rainfall was similar to three or four of the previous most severe droughts. So why are the climatologists at Monash University and the Bureau of Meteorology describing it as the worst? The reason is that temperatures in 2002 were significantly higher than in other drought years, at least since 1950. Prolonged higher temperatures caused a marked increase in evaporation rates, drying of soils and stress on crops, animals and vegetation. The gross value of farm production is forecast to fall by around 20 per cent for 2002-03

The drought was linked to El Niño - most Australian droughts are - a phenomenon that is part of natural climate variability. We expect, on average, warmer day-time temperatures and slightly cooler night-time temperatures during droughts because of the clear skies. But the 2002 maximum temperatures are the warmest of any year since 1950 and unusually warm when compared to the five major droughts since 1950 - facts consistent with an influence of global warming.

The higher maximum temperatures and drier conditions also created greater bushfire danger than in previous droughts. During January 2003, huge areas of Australia's alpine national parks were burned and Australia's national capital, Canberra, lost over 500 houses to firestorms erupting from adjacent forests.

Australia's ecology is simultaneously robust and fragile. Robust to drought and fires, it has been shaped by these forces over thousands of years. But its fragility can also be seen in species at risk of extinction and in examples of ecological niches being transformed over very short spaces of time. In the 19th century, open treed grasslands in parts of eastern Australia were transformed into thick woody scrubby country within a decade when a combination of forces occurred - extinction of small marsupials, severe drought causing de-stocking followed by widespread flooding. Millions of seedlings, previously kept in check by marsupials and periodic grass burning by aborigines, became established. During the 2002-03 high risk fire season, wildlife experts fear that rare wildlife species will be burned to extinction, and some of them claim that our sub-optimal management of fire-prone forests is partly to blame.

And in recent times (ecologically) new forces are at play. There has never been a population of 20 million humans in Australia before. Nor has the landscape ever been used in the past to feed 20 million Australians and maybe 3 times that number of people elsewhere. Communities and families build and live close to significant fire risk areas. A debate has been flaring and subsiding for many decades on how best to manage forested and other fire-prone areas. Public policy on fire management is influenced by a less than complete understanding of the robustness and fragility of the ecologies, by fears of litigation from both action and inaction, and by the influence of divergent lobby groups. And now our droughts seem to be hotter and therefore riskier.

When the "worst" drought happens and a bad bushfire season flares, debates also flare. The debate has already flared over leaving native forests in their "natural" state or managing them with a program of fuel (mostly ground litter) reduction. The debate has already begun over whether it is the enhanced Greenhouse effect or just natural climate variability that has made the 2002-03 drought so hot. If, however, droughts are hotter and riskier, past wisdoms may need some rethinking, past practices may need some adjustment:

• Fire management strategies of the past may no longer mesh with the changing nature of Australian droughts and the increasing fragility of some ecologies, and may need fine-tuning.
• Housing standards in fire-prone areas may need to be given the same authority as standards for tropical cyclone areas.
• Previous views that the cost was too high for the small gain expected from Australia signing the Kyoto protocol, may need to be adjusted in the light (heat) of increasing costs of not signing (bearing in mind that much of the benefits are likely to be long-term).

Each group involved with these burning hot issues is under a different set of pressures - individuals rebuilding to house the family, local communities wishing to maintain some control in shaping their community and environment, ecologists and climatologists required to give expert opinion based on best available assessments, elected representatives asked to find quick fixes, legislators and regulators balancing individual freedom vs community rights. The challenge is to mould those divergent views, competing pressures and growing bodies of knowledge into solutions that are appropriate to the scale and scope of the problem.

This is precisely the same challenge for any environmental issue anywhere in the world - matching the scale and scope of the problem to appropriately scaled, appropriately flexible and effective responses.

Mary Voice
mvoice@bigpond.net.au