“The papers provide the basis for a much-improved understanding of the likelihood of global warming caused by a build-up of greenhouse gases in the atmosphere, of the possible effects in Australia of changes in climate, and of the measures that can be considered to reduce the emissions of greenhouse gases.”
“If global warming occurs, it is likely to affect many aspects of our lives in the years ahead and to require considerable changes in accepted patterns of behaviour.”
-1989, Bob Hawke, Australia’s 23rd Prime Minister.
Foreword to the report of the First Prime Minister’s Science Council on “Global Climate Change Issues for Australia” held at Parliament House on 6 October 1989.
The threat of climate change was in the periphery in Hawke’s time, but still important enough to him and his Cabinet to hold the first Science Council on this topic.
Now, 30 years later, the world is facing serious consequences with many species, habitats, and humans already changing normal “patterns of behaviour”.
Bob Hawke championed a range of environmental decisions, such as protection of the Franklin River, and giving the Commonwealth powers to protect World Heritage sites, yet was also known for effective economic reforms.
Today we need similarly impactful policy-making and legal reforms to protect the Australian environment from climate change.
These protections need to consider BOTH mitigation – reduction of greenhouse gas emissions – and adaptation – interventions to manage the unavoidable changes due to climate.
Innovative leadership is needed as climate interventions across Australia’s many ecosystems will require approval and cooperation from private landholders, indigenous owners of land and sea country, all levels of government, and be consistent with Australia’s obligations under international law.
Intervention to aid species facing climate impacts
Interventions for individual species include assisted colonisation of threatened species to new locations with future climate conditions that match the environment in their present habitat.
Identifying species that lack the genetic variation and phenotypic plasticity to adapt to warmer or more variable conditions is key for improving the outcomes of these interventions.
Species can also help protect ecosystems — for example planting eucalypt species from warmer populations into currently cooler regions so the genetic diversity in the local population is augmented to increase the chance that the population will cope with a warmer climate.
Actions at an ecosystem or landscape scale will help sustain other species, such as koalas and parrots that feed on the eucalypts.
However, limiting climate change is critical for protecting the large number of species that lack sufficient adaptive capacity to keep up with the rates of change.
Ecosystem interventions can also reduce a non-climate stressor, for example reducing nutrient runoff in waterways that flow into the Great Barrier Reef.
The cooperation of private landowners is needed in many regions of Australia to minimise additional non-climate stressors.
Through state and federal governments zoning of land for new protected areas and nature corridors will allow ecological communities to naturally shift as the climate changes.
In urban and coastal areas, zoning for new developments must also take climate into consideration and provide refuges and pathways for species to move.
It is not just for nature — new developments on low land coastal areas could potentially be costly to communities and the finance sector if the worst scenarios for sea level rise occurs.
Legal challenges from landholders will undoubtedly occur as landowners seek to protect their property interests.
However, environmental, social and economic values in maintaining natural coastal systems will need to be assessed in terms of the common good in coastal Australia.
Large change is coming
Projecting the impact of rising sea levels is driven mostly by climate models that utilise several different future greenhouse gas emissions in their projections.
However, for sea level projections over the next 100 years, these models generally only consider sea level rise due to water expansion through ocean warming.
The potential contribution from ice sheet melting is either omit or considered in only a very rudimentary way which places considerable uncertainty on sea level projections. No model is perfect, but they are still an important tool to guide decision-making.
However, when it comes to interpreting models we must always remember the limitations and assumptions of each model.
Climate models that predict a 1.5℃ increase in annual mean temperature are useful but, they are not designed to estimate short-term temperature extremes where the impacts can be most devastating (e.g. widespread coral bleaching on the Great Barrier Reef).
Over the next decades, we may experience extremes where warming is well above 1.5℃ seasonal climatology conditions.
Unprecedented climate extremes and temperature fluctuations are potentially a bigger threat to ecosystems than increases in annual averages.
Paris target requires ‘negative emissions’
The Paris Agreement seeks to limit global warming to below 2℃ with an aspirational target of 1.5℃ above pre-industrial levels.
To achieve these targets, urgent action is needed to significantly reduce global greenhouse gas emissions.
However, IPCC modelling scenarios suggest that more ambitious mitigation strategies will not, on their own, be enough.
To meet these targets, especially the more aspirational 1.5℃, it will be necessary to produce ‘negative emissions’ by drawing carbon dioxide directly from the atmosphere to store it permanently in terrestrial or ocean sinks.
Land-based proposals include bioenergy with carbon capture and storage and direct air capture technologies.
Prominent ocean-based proposals include ocean fertilization and ocean alkalinity enhancement.
However, most of these proposals are at a very early stage of development and the extent to which they can feasibly be scaled-up to deliver the magnitude of negative emissions for a 1.5℃ target is uncertain.
These proposals present various environmental risks and socio-political challenges and require the development of robust governance mechanisms at local, national and international levels.
Overcoming barriers to action
Legal restrictions for some interventions privilege the rights of private property owners and indigenous peoples.
Any action or the movement of species onto such lands may need to be considered for the greater good of our linked environment and economy.
To make important climate change adaptation and intervention possible we need well-informed and effective policy-making to overcome the barriers for action at both domestic and international levels.
This includes establishing processes to identify the type and scale of interventions to implement.
With every intervention there are a number of legal and ethical considerations – such as which species should be moved and which habitats should be created.
Trials may need to occur in the face of imperfect knowledge, and we will need to ensure that the benefits of acting will outweigh the costs of any negative impacts that might arise.
Ultimately, we can only rely on the best available knowledge and data when it comes to proceeding with interventions.
Developing an adaptation decision-making framework is a difficult task but, the positive outcomes of early action will significantly benefit the natural environment, societal wellbeing and our economy.
Samuel C. Andrew is from the CSIRO’s Land and Water, Alistair Hobday and Richard Matear are from the CSIRO’s Oceans and Atmosphere, Bruce G Thom is Emeritus Professor at The University of Sydney, and Kerryn Brent is from The University of Tasmania.