Net-zero by 2050 not enough, Australia’s leading climate scientists say

The Australian Greens MPs

Leader of the Australian Greens, Adam Bandt MP, has commended Australia’s leading climate scientists for their courage in warning that both Liberal and Labor’s climate policies are dangerously inadequate.

Three of Australia’s leading specialists on climate change – Professor Will Steffen, Professor Lesley Hughes, and Dr Pep Cannadell – have today warned that Australia needs to hit net-zero carbon emissions before 2050, including significant reductions in the next ten years, if we’re to keep global warming well below 2 degrees and honour the Paris Agreement.

Professor Will Steffen was the scientific expert advising Labor on the carbon price as part of the Multi-Party Climate Change Committee.

As stated by Leader of the Australian Greens, Adam Bandt MP:

“The verdict is in. Australia’s top scientists have said that the Liberals’ climate targets won’t stop runaway global warming but nor will Labor’s ‘net zero by 2050’.

“The scientists back the Greens in demanding real action by 2030 and a plan for coal, because otherwise it will be too late.”

“We need critical action in the next decade if we’re to protect ourselves and the planet from the worst impacts of global warming.

“At current rates, we risk hitting 1.5 degrees of warming by 2030. That’s just ten years from now.

“Beyond that, we’ll start hitting tipping points that will make it harder, if not impossible, to keep climate change under control.

“By the end of this decade, scientists fear we could see the collapse of ice shelfs in Antarctica that would lead to 3-4 metres of sea level rise, all in my children’s lifetime.

“This disastrous summer of fires happened at just one degree of warming and things stand to get worse. This should be a wake-up call that we need action now, not in decades to come. We don’t have any time to waste.”

Selected comments from Will Steffen’s article for The Conversation:

Perhaps the most robust way to assess whether a proposed climate action is strong enough to meet a temperature target is to apply the “carbon budget” approach. A carbon budget is the cumulative amount of carbon dioxide the world can emit to stay within a desired temperature target.

Once the budget is spent (in other words, the carbon dioxide is emitted), the world must have achieved net-zero emissions if the temperature target is to be met. […]

The Intergovernmental Panel on Climate Change (IPCC) estimates that from 2020, the remaining 1.5℃ carbon budget is about 130 GtC (billion tonnes of carbon dioxide). This is based on a 66% probability that limiting further emissions to this level will keep warming below the 1.5℃threshold.

Current global emissions are about 11.5 GtC per year. So at this rate, the budget would be blown in just 11 years. […]

This is where the “net-zero emissions by 2050” target fails. Even if the world met this target, and reduced emissions evenly over 30 years, cumulative global emissions would be about 170 GtC by 2050. That is well over the 130 GtC budget needed to limit warming to 1.5℃. […]

So, what would an effective climate action plan look like? In my view, the central actions should be:

  • cut domestic emissions by 50% by 2030
  • move the net-zero target date forward to 2045, or, preferably 2040
  • ban new fossil fuel developments of any kind, for either export or domestic use

For background – what’s the difference in outcomes between 1.5 and 2 degrees?

From: Climate Council -The Difference Between 1.5 and 2 Degrees Warming

  • Loss of plant species – 2x worse
  • Loss of insect species – 3x worse
  • Further decline of coral reefs – from 70-90% gone to 99-100% gone
  • Days of extreme heat – 2.6x worse
  • Instances of total sea ice melt in the Arctic – 10x worse

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