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‘The Critical Decade’: expert views on the Climate Commission’s first report

Act now or risk our way of life, Climate Commission says. AAP

The Critical Decade” for climate change action is upon us.

The Climate Commission’s first report, released today, says unless Australia takes action before 2020, our way of life is at threat.

“The risks have never been clearer and the case for action has never been more urgent,” its authors argue.

We asked Australia’s climate science experts to review the report’s findings. Some of these comments are courtesy the Australian Science Media Centre.

Professor David Karoly, School of Earth Sciences, University of Melbourne

This report from the Climate Commission is a synthesis of the latest scientific evidence on climate change and its impacts on Australia.

It has been independently reviewed by leading climate scientists from CSIRO, the Bureau of Meteorology and universities in Australia.

Its conclusions and key messages are clear; they are the same as those reached recently by the US National Academy of Science, and by all other major scientific academies around the world:

  • The global climate system has warmed over the last hundred years.

  • Most of this warming is due to increases of greenhouse gases in the atmosphere due to human activity.

  • This warming is already having adverse impacts in Australia and around the world, with increases in hot extremes and increases in sea level.

  • Decisions made this decade will largely determine the extent of warming experienced over the next two generations.

A decision not to take action to substantially reduce greenhouse gas emissions is a decision to make the problem worse, a decision to cause more hot extremes and to increase sea levels even further.

Professor Steven Sherwood, Physical Meteorology and Atmospheric Climate Dynamics at the Climate Change Research Centre, University of New South Wales

The science in the report is familiar from other reports such as the Copenhagen Diagnosis and recent CSIRO report, and again highlights the urgency of starting to turn away from our emissions-growth trajectory as soon as possible if we want to avoid potentially disruptive climate changes.

One thing I liked in this report was its emphasis on ocean acidification, a consequence of carbon dioxide build-up that is almost as scary as climate change but has not received nearly as much attention.

It is a much harder consequence for critics to question than global warming, since ocean acidification is relatively more straightforward.

There is also a good discussion of the difference between rate and timetable thinking vs. budget thinking when it comes to emissions.

Rate and timetable thinking has dominated political discussions so far, but budget thinking is more appropriate to the physics of the problem and probably easier for people to grasp.

Professor Ove Hoegh-Guldberg, Director of the Global Change Institute, University of Queensland

The report is a comprehensive synthesis of our current understanding of climate change and its impacts, based on solid evidence-based, peer-reviewed science. It is this type of document that should guide politicians and compel them to act.

It is vitally important that responsible governments everywhere face up to the urgency of the situation we face with respect to climate change, and to act on the recommendations of their experts.

They must listen to the experts, devise meaningful responses and act immediately on this important issue.

Prof Will Steffen and the Climate Commission have provided a very clear description of science behind climate change and its impacts.

The evidence produced within the report has been published in the peer-reviewed literature and collated by bodies such as the Intergovernmental Panel on Climate Change.

The latter produces regular rigorous and, albeit conservative, scientific consensus reports on the science behind climate change, its impacts and the solutions.

The report collates information that underpins our current concern about natural ecosystems such as the Great Barrier Reef. This particular ecosystem is under threat from warming sea temperatures and steadily acidifying oceans.

If these conditions continue, the competitive advantage that reef-building corals enjoy on reefs such as the Great Barrier Reef will tip in favour of less charismatic organisms such as seaweeds and other non-calcifying organisms.

This has serious implications for industries such as tourism and fisheries which bring in over $6 billion each year to the Australian economy, and employ over 60,000 people.

The threat to ecosystems such as the Great Barrier Reef is real and growing. If we continue along the current business-as-usual pathway, we will soon be at concentrations of carbon dioxide and sea temperatures which we know are harmful to corals and the reef systems they build.

At the current rate at which we are emitting carbon dioxide (over 2 ppm per year) we will arrive at these conditions by 2050.

This has serious ramifications for coral dominated ecosystems such as the Great Barrier Reef, which will transition into non-coral dominated states that will last centuries.

The result will be the ecological extinction of the world’s largest reef system along with hundreds of thousands of species that depend on coral reefs for their existence. This will put a serious threat to sustainable industries such as tourism and fisheries upon which many Australian families depend.

The situation with coral reefs is only part of the story. Other Australian world heritage listed sites such as Kakadu and the Daintree are threatened by rapid anthropogenic climate change.

In the case of Kakadu, acceleration of sea level rise will soon see large areas of Kakadu inundated with sea water. That will mean the end of the world’s largest freshwater swamp and the associated bird habitat.

At the same time, increasing temperatures will mean the cloud layer that bathes forests at the top of the Daintree ranges will no longer do so, causing rapid drying of those forests and the loss of huge amounts of Australia’s precious and unique terrestrial biodiversity.

Australia is extremely vulnerable to climate change and should be leading international effort to rapidly reduce emissions from the burning of fossil fuels and land-use change.

Unfortunately, we have a bad track record in terms of our carbon footprint and our role as the leading exporter of coal.

If the carbon dioxide emissions from coal cannot be sequestered safely, one has to question the logic of Australia promoting its use internationally given our vulnerability to climate change.

More on this story at “Fix climate by 2020 or face huge costs”.

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