Australian beaches have been disappearing faster and with more permanence, no question; the causes are not so simple and neither are the legal consequences.

If the seas reclaim your front yard — or your whole house — who can you sue? It's a question lawyers are going to be addressing more urgently, as coastlines are radically redrawn.

There's this eternal truth: coasts erode. If you build on the shoreline, sooner or later you'll be in the drink, even if that takes a millennium or two. No law will compensate you for Mother Nature's revenge.

Direct human intervention — such as dredging of shipping channels, seawalls, artificial harbours — impacts on coastal ecology in dramatic and often unpredicted ways. Mackay, McEwens Beach and Stockton are clear examples.

Then there's the link between coastal recession generally and climate change, of which the most obvious relevant impact is rising sea levels but which has multiple interlocking consequences including run-off and vegetation loss.

The combination of these factors will do a judge's head in, trying to apportion legal responsibility when somebody's property has slipped beneath the waves. At this stage, the law is a long way from figuring that out.

Where are we currently at, legally?

Under Australian law, the notionally easiest paths to compensation are by claims of negligence or nuisance. That means proving that someone (the defendant) owes a duty to the affected property owners and has failed in that duty, either by act or omission.

The more obvious the cause of the loss, the more simple the legal case will be. If the government, council or a private company built a seawall that caused the neighbouring beach to disappear and take everyone's beach shacks with it, then those owners may have a theoretically straightforward case for damages. It's never that simple, however, because the defendant can point to the inherent complexity of coastal erosion, including the effects of climate change, for which it is not responsible. The beach might have been terminal anyway.

The United States has seen a raft of civil actions against oil and gas companies like Exxon Mobil and Chevron, suing for nuisance, negligence or trespass on the basis of their alleged failure to limit the volume of fossil fuels they have pumped into the atmosphere, and its impact on communities and private property.

The role of government

A more obvious defendant on the climate change front might be the federal government. The UN's Human Rights Committee recently delivered a landmark ruling, confirming the critical role of governments in stopping rising sea levels. It said that "without robust national and international efforts, the effects of climate change ... may expose individuals to a violation of their rights" to life and to be free from degrading treatment, for example by having access to safe drinking water. This was in the context of a claim by Kiribati citizens for asylum (Kiribati being one of the first nations that will go under as the oceans rise).

The argument is that national governments have legal responsibility for the liveability of our environment, and may become liable for the consequences of climate change if they negligently fail to take steps to mitigate its effects.

Civil claims against governments and corporations have had limited success so far, often being dismissed because of the impossibility of directly linking the defendant's conduct to the physical cause of the loss. An academic called Douglas Kysar put the problem clearly: climate change is "a collective-action problem so pervasive and so complicated as to render at once both all of us and none of us responsible". The courts don't like that kind of uncertainty.

A two-way street

In one sense, there's a good argument that the law needs to urgently adapt in response to the fact of climate change and the consequences of failure to deal with it. This would require a far more flexible understanding of causation and legal liability.

On the other hand, the increasing obviousness of the effects of climate change cuts both ways. The law has always applied a principle called voluntary assumption of risk; if you build your house under water, don't be surprised (and don't blame anyone else) when it leaks. We all know the beaches are under threat. Mitigation of risk is, like climate change itself, the responsibility of no single person or institution. Basically, don't buy beachfront land.

There are other, more exotic possibilities for litigation in Australia, as yet untried. One is the constitutionally protected right to compensation when your property is compulsorily acquired by the federal government. Sooner or later someone will have a crack at claiming that the government's climate policies involve, through the inevitability of their consequences, the acquisition of coastal property by allowing it to disappear. Kind of a conscious choice: the price of keeping fossil fuel industry jobs being paid by coastal property owners who lose their land. Novel argument, but worth a try.

The other field is human rights, including the right to not be arbitrarily deprived of property. Europe, the US and Latin America have seen cases against governments that engage the interplay between human rights violations and environmental law. In Australia, the problem with following suit is that we have no enshrined human rights, so all those international conventions we've signed up to aren't actually part of our law. We'll need a bill of rights before this becomes a real prospect.

The one thing we can say for sure is that, as more beaches disappear, more litigation will follow.

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