How a 2°C rise will change the face of WA
Katherine Fleming
Two degrees. It doesn't sound like much but if - or, as some scientists say, when - WA gets
that much warmer it will look different. If temperatures rise and the South West continues to dry,
farming belts will likely move south, forests will struggle, some animals will be pushed towards
extinction and the weather in Perth and Sunbury could be more like Geraldton's. Temperatures
are projected to rise in Australia 0.6-1.5°C by 2030. and 2.2-5°C by 2070 if greenhouse gas
emissions continue to grow. But regardless of our actions, a 2°c warming in the long term was
already 'locked in', Andrew Ash, director of GSIRO's Climate Adaptation National Research
Flagship, said. The United Nations' Inter-governmental Panel on Climate Change's predictions
for. Australia include more frequent and intense heatwaves and fires, as well as floods,
landslides, droughts and storm surges, as well as less snow and frost
Biodiversity
The triangular area between Shark Bay and Esperance is Australia's only global biodiversity 'hot
spot'. It was also 'one of the canaries in the coalmine for climate change', World Wildlife Fund
WA director Paul Gamblin said. The IPCC noted: 'Many narrow-ranged endemic species will be
vulnerable to extinction with relatively small warning.' A heatwave last year resulted in the mass
death of more than 100 endangered Carnaby's cockatoos near Hopetoun. Modelling showed
mainland quokkas, which prefer cool, wet conditions, would attempt to move south but run
out of room by 2070, under the most extreme temperature scenario. Some species would
benefit and others would adapt, Colin Yates, manager of the Department of Environment and
Conservation's. biodiversity and climate char1ge unit, said. But others could die out and habitat
destruction would make it difficult for those that needed to migrate. WA's iconic forests were
also vulnerable, Dr Yates said...'We don't know how quickly those might become under threat,'
he said. Marine ecosystems were at imminent risk of the worst spate of extinctions in millions
of years from threats including climate change and overfishing, the International Programme on
the State of the Ocean reported.
Health
As well as direct physical injuries and fatalities from extreme weather events, hotter and drier
conditions could have potentially 'catastrophic consequences' for melanoma rates as people
spend more time outdoors, a Department of Health report on global warming says. Scientists
say global warming would be felt through an increase in hot days, with days above 35°C
projected to increase from 28 to 67 by 2070, if emissions aren't reduced. The most vulnerable
to health problems from climate change, including heat-related deaths, include the elderly and
young, the disabled, homeless or sick. Jim Dodds, the department's director of environmental
health, said it had focused on extreme weather events but was increasingly looking at air
quality, including more potential for smog and bushfires. A jump in mosquito numbers after high
tides in Peel this year gave a glimpse of potential conditions with higher sea levels. 'Climate
change will give us sea level rises and areas will be inundated and some of those will be closer
to existing populations than they currently are,' he said. Mr Dodds said water availability and
quality were also likely to be a major concern, including use of recycled water and more chance
of contamination in stagnant pools or warmer water.
Agriculture
Farming belts in the South West may shift south-west by 30-50 km by 2030 under the
worst-case scenarios, according to the Department of Agriculture. While higher carbon dioxide
levels could fuel more crop and pasture growth,· those benefits would reduce as temperatures
continued to rise. Wheat production could decline by 8 per cent by 2030 and 12 per cent by
2050, with similar declines in sheep meat. The department predicted the area where farmers
could grow grain crops would contract and there would be fewer sheep in the Wheatbelt. The
challenge of more fly strikes and lice and the need to cart and store water would make farming
more difficult. In the Kimberley, farmers may need to consider moving into other industries, such
as ecotourism and biofuel trees. Dr Ash said there were also opportunities. In the traditionally wet
southern part of WA, less rainfall might open up more areas to cropping. About half of the 15 per
cent drop in rainfall in the South West since the 1970s has been attributed to climate change.
Planning
Under a 1.1 m sea level rise, between 20,000 and 30,000 WA homes would be at risk of
inundation, according to the Federal Department of Climate Change and Energy Efficiency.
It would also threaten roads and railways. The Climate Commission recently reported seas
were rising more quickly off WA than elsewhere in Australia and a national rise of 0.5-1 m was
plausible by 2100. Higher sea levels and storm surges would become a major planning issue,
Dr Ash said. 'The immediate prognosis is not too bad but we need to plan in order to not put
people in harm's way,' he said. 'Roads or bridges or dams we want to last for 100 years need
to be built for tomorrow's climate.' The Town of Cottesloe gave the go-ahead for development
of a 100-year plan for the beachfront. The City of South Perth is investigating future
flood-prone areas and planning to raise river walls. David Ness, from the National Climate
Change Adaptation Research Facility, examined planning for Sunbury, using Geraldton's
weather as a guide.
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