Australia's climate will move into unpredictable territory if global warming reaches 2 degrees. Photo: Glenn Campbell
As the world endures a third straight year of record-breaking heat, a new study has given fresh insight into what global warming is likely to mean for Australians if it is not curbed...
Using new methodology, Germany-based researchers Climate Analytics found the difference between 1.5 and 2 degrees of warming – the two goals included in the Paris climate deal – would be much greater in terms of extreme events and disasters than previously believed.
Climate change (and how to tackle it) is largely responsible for the highest turnover of Prime Ministers in Australia since 1945. Animation by Matt Davidson.
Already, at about 1 degree warmer than pre-industrial times, parts of the world are experiencing more frequent and intense extreme events – heatwaves, unusual dry spells, dumping rainfall, massive coral bleaching.
The report says the upper end of current climate extremes would be "the new normal" at 1.5 degrees warming - which could be just 10 to 20 years away under the current trajectory.
At 2 degrees, the picture is much less clear – the climate system would move into uncharted territory.
In southern Australia, the report suggests:
- Heatwaves would be on average 13 days longer at 1.5 degrees, and 20 days longer at 2 degrees.
- Dry spells would be 3.5 days longer at 1.5 degrees, and six days at 2 degrees.
- Water availability through run-off after rain would be down 7 per cent and 13 per cent.
- Intense rain storms would be either 2 or nearly 3 per cent heavier, depending on the temperature increase.
For northern Australia, the change in heat is much more dramatic - heatwaves would be on average 37 days longer at 1.5 degrees, and 52 days longer at 2 degrees. Water availability would be reduced, but not by as much as in southern states.
Monthly global temperatures anomaly.
Commissioned by the Climate Institute research and lobby group and reviewed by Australian scientists, the report says one of the greatest risks would be to human health during extended heatwaves.
It says agricultural productivity would be cut in southern Australia and there would be increased risk of bushfires.
Climate Analytics chief executive Bill Hare, a physicist with 25 years' experience in climate science, said the scale of the difference in life under 1.5 and 2 degrees warming was surprising.
"This reinforces the evidence of the damage that will be done if we don't manage to avoid the 2-degree limit. It might be the difference between the extinction and survival of some parts of the Great Barrier Reef," Dr Hare said.
"Unambiguously, heatwaves are already occurring longer than they did in the past in many regions, with great effect on agriculture and human livelihoods. And we're seeing an increase in precipitations intensity, some of which is more extreme than some would have expected."
He said the projections in the study were drawn from "complex energy system models that describe the real world".
"It's really now a matter of whether we can take action fast enough to get emissions down fast enough," he said.
Under the deal struck in Paris in December, nearly 200 countries including Australia agreed to aim to stabilise global warming well below 2 degrees above pre-industrial levels, and less if possible.
Despite this, the Climate Analytics report suggests national targets to cut emissions submitted at the talks would only limit warming to about 3 degrees. Several countries – including Australia – have been assessed as not having policies that can deliver even those commitments.
Climate Institute chief John Connor said the new research illustrated in scientific and economic terms why Australia urgently needed to introduce a long-term national agenda to deal with climate change.
He said a promised review of climate policies next year needed to set a pathway to zero emissions, give business certainty to invest in clean energy and move the issue from the fringe so that it was factored into all relevant decision-making.
"Achieving emission reduction targets will require transformation," Mr Connor said. "Not achieving them will require even greater transformation as we struggle to cope with growing climate impacts."
original story HERE
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