These scientists were absolutely correct to distance themselves from the Climate Change Authority’s main report. The main report does not go far enough and would put Australia at the bottom of the pile in terms of ambition, below all other developed countries and below many developing ones. Calculations of equitable contributions to meet climate targets have been performed by Malte Meinshausen from the University of Melbourne. See https://www.mitigation-contributions.org/. These show that Australia needs to make around 50 per cent cuts in emissions on 2005 levels by 2030, twice its current commitment.

The Climate Change Authority's report does not address further emissions reductions targets. In not doing so the Authority is acting contrary to the scientific evidence and contrary to the public interest.

With the increase in the global average temperature already nearing 1.5℃ above its preindustrial level, delaying very strong actions to reduce emissions, as the dissenters point out, will lead to an increase of greater than 2℃ over the next few decades; it has only taken from 2000 to the present to go from about 1℃ to 1.5℃.

And warming is not all that is happening. Large amounts of ice are now being lost each year from the Antarctic and Greenland ice sheets and the rate of loss will surely go up, further accelerating the rise in sea level. Precipitation is more and more occurring in heavy amounts, leading to flooding, while at the same time the warmer temperatures lead to faster drying of the soils between the rains. The notion that only slowly reducing fossil-fuel based CO2 emissions and can still meet the goals of the Paris Agreement is just not true - every nation needs to be doing much more than it has committed to do, not less.

The dissenting report by Climate Change Authority board members Professors Hamilton and Karoly illustrates just how wide the difference is in informed views on the issue of climate change policy. It also begs the question of what the role of independent statutory bodies should be in this debate. Should the CCA give advice that is calibrated to political circumstance, or advice that is predominantly guided by science and economic fundamentals?

The Climate Change Authority has been known for strongly principled advice for ambitious climate policy, such as its recommendations for a carbon budget. Last week’s report on a recommended climate policy toolkit is much more pragmatic. Its recommendations are what many see as politically feasible in Australia now.

That pragmatism means a piecemeal approach. The report lacks a vision for the longer-term policy framework needed to get Australia on track to a low-carbon economy. It frames climate change action mostly as a cost, rather than as an opportunity for economic renewal.

The CCA’s intent clearly is to help policy progress in the medium term. But it risks locking-in a policy suite that will be costly or less effective. And if the CCA’s recommendations are misconstrued as being ambitious, we could end up with policy that falls far short of these recommendations.

We recently published this paper http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149406
 
It presents a global energy use model which has accurately tracked global energy use for the last 60 years (See figure 1).

The calculations are based on the global population, energy use per person and economic growth.
If we continue down the forecast population growth rate, average energy use per person and average economic growth rates modelled over the last 60 years, we may burn:

1. all the C that we can and stay below 1.5℃  by 2020 (See figure 3A)
2. all the C that we can and stay below 2℃  by 2030 (See figure 3A)

 
As the Earth absorbs about 50 per cent of global emissions this means that we need to reach 50 per cent emissions reductions at these time points.
 
The model accounts for all people (not just the wealthy) having average economic growth rates. Failure to do so would essentially mean that we condemn the 50 per cent of the global population living on $2.50 per day to long term poverty.

Australia has a wealth of solar energy and space.  The debate is not just about cost, but also significant opportunities.
 
I should also point out that, globally, about 20 per cent of energy is used in the form of electricity and 80 per cent as fuels. So to reduce emissions below 50 per cent we urgently need renewable fuel solutions.

A day after Father's Day, I cannot help but fully support Karoly and Hamilton in writing a report on climate change that dissents from the official government rendering.  Their dissenting argument has been supported by the majority of scientists for years and had to be re-stated yet again when the Abbott government set the 28 per cent target leading up to the Paris agreement.  

By maintaining a soft rate now in favour of a steeper rate from 2030 onwards does one thing - it shunts the entire problem, with far greater pain, into the future.  This is no longer an issue of international equity but one more issue of inter-generational equity in Australia - just chalk it up with youth unemployment, HECS debts, impossible housing costs and an economic system that disavows the existence, let alone needs, of children and their carers. 

Younger Mums and Dads in Australia are genuinely worried and have been for a long time.  Children have no voice.  Neither have democratic clout.  Whereas for another conspicuous generation, the policy-makers now will likely be dead or pensioned by the time our children have to deal with the consequences.

The government, whatever government is in, simply cannot have their cake and eat it too.  If you argue on one hand that we can't afford to adapt fast enough now lest it hamper our present consumption and growth, then how can you justify our children having to adjust even faster down the track, when consumption and growth will be more challenged by 1. larger populations, 2. degraded resources; 3. annual wildfires and bigger natural disasters, 4. as yet unknown political and climate parameters like possible tipping points.

The level of mass denial among some Australians has become staggering.  We've known about the problem for decades, allowed it to continue simmering in the background whilst increasing, not decreasing, carbon-intensive consumption.  Book another overseas holiday and leave it for the grandchildren to sort out! 

We must either make an effort to tackle the problem we created or get out of the way so others can.  Dragging our feet on an international agreement when we're one of the wealthiest nations in the world is not only a slap in the face to the rest of the world but also to our children. They all deserve better.

As highlighted by continuing increases in global temperatures and serious impacts such as the bleaching of the GBR this year, substantially more ambitious emission reductions than are currently Government policy are required to achieve the Targets agreed to in Paris.  The current Government targets are clearly inadequate.  Targets commensurate with the urgency and seriousness of climate change are required now.

Nobody is claiming that we know everything about climate change but to deny its existence is ridiculous.  Carbon dioxide is a known heat-trapping gas and its concentration has nearly doubled in the atmosphere since the beginning of the industrial age.  That the Earth will become warmer is not speculation or conjecture but simple physics.

That is not to deny that we face large uncertainties ahead: How much higher will CO2 concentrations rise?  What will be their impacts on climate cycles and precipitation at local scales?  What will be the biological consequences for heat-sensitive species such as coral reefs and cool-adapted species living on mountaintops and colder realms of the Earth?  How much more frequent will killer heat waves or droughts become?

Ultimately one realises that standing by and doing nothing about climate change is a lot like playing Russian Roulette—except that the gun is pointed not only at our own heads but also at the heads of our children and grandchildren, who will have to bear the brunt of our planet-polluting ways.