The hearings will attempt to instruct countries on how to protect the environment from the impacts of greenhouse gases, and what obligations they may have if they fail to do so.
The ICJ is hearing pleadings in response to a UN General Assembly request last year for an opinion on "the obligations of States in respect of climate change." Advisory opinions of the ICJ are non-binding but are legally and politically persuasive.
The Australian argument relied heavily upon existing multi-lateral agreements such as the Paris agreement and that, in effect, this and other treaties displaces all other international law.
Central to case before the ICJ is the customary obligation of prevention. On this, Australia argued that the rule of prevention does not apply to harm caused by greenhouse gas emissions. According to Australia's pleading, emissions cannot meet the conventional test that harm must involve a direct and proximate harm from an identifiable source spreading from one state to another, such as pollution flowing through a river from one state to another. Further, the harm from greenhouse gas emissions is from the cumulative build up; historic emissions from multiple state and countless individual actors. Harm is widespread and not localised.
The Australian government also argued that there was no international agreed or consistent view of how to apply the rule of prevention in the context of greenhouse gas emissions.
States have not been able to agree on how to apply the rule of prevention in multi-lateral forums such as the United Nations Framework Convention on Climate Chante (UNFCCC). As such, the international court should not try to extend the rule of prevention to greenhouse gas emissions.
Finally, Australia argued if the rule of prevention does apply; compliance with UNFCCC and the Paris agreement already meet any prevention requirements.
"The fact the UN General Assembly asked the ICJ last year for an opinion on the obligations of states in respect of climate change, is proof that a significant number of nation states are not satisfied with current multi-lateral agreements and are seeking a legal opinion, unconstrained by obligations to protect national interests that bind negotiators at forums such as the UNFCCC", said Leanne Minshull, Strategic Director of the Australia Institute.
"Listening to the oral pleadings of Australia and it's consistent referral to existing multilateral agreements, it felt as though they were saying to the court - relax we already have this under control. Whether it's Australians facing a climate fuelled cost of living crisis, or a Pacific islander watching their country be washed away - ordinary people understand, we don't have this under control.
"As an Australian, I would have liked to hear our government plead a case that looked for global solutions rather than rely on sophistry to limit our legal obligations to ourselves and others."
