The most urgent action is the shift to renewable energy. We cannot continue burning fossil fuels. All arguments that this is not realistic, that oil, gas and coal are a necessary part of the energy mix or could only be phased out in the long run, or John Key's assertion that New Zealand's offshore oil and gas explorations would be minuscule compared to Saudi Arabia's, are cheap excuses. They avoid the central question of whether the market advantages that fossil fuels enjoy can be tolerated any longer.
Viable options for dismantling those advantages include stopping subsidies for fossil fuels (estimated by the International Energy Agency at nearly $900 billion a year), a global carbon budget with national allocations, carbon pricing or an effective emissions-trading system.
However, any of these options require an understanding that the atmosphere is not an asset freely available to anyone, but a common good for all in need of uncompromising protection by those who govern on our behalf.
At present, the atmosphere resembles a wild, uncontrolled rubbish dump. Polluters are free to sink their carbons into the atmosphere simply because they can. From an economic perspective, this is an enormous incentive to ever increase the production - and consumption - of oil, gas and coal, especially as long as they are so advantaged over renewables.
To reverse this absurdity, costs for fossil fuels need to go up, so renewables can become competitive. Legally, the closing down of the "rubbish dump" can be achieved by recognising the atmosphere as a global commons or a common heritage of humankind. Practically, this involves an automatic charge for any excessive use - no negotiations needed.
The justification underpinning any climate action is critical. To this end, the Paris Agreement preamble mentions climate justice and the "intrinsic relationship" that climate change actions have with sustainable development and eradication of poverty. It refers to human rights, the rights of indigenous peoples, migrants and children and notes "the importance of ensuring the integrity of all ecosystems ... recognised by some cultures as Mother Earth".
These statements are not just sentiments, but reflect existing law and should be the sole basis for thinking about climate change. As long as our political leaders do not accept this, the Paris Agreement will remain an empty promise.
Professor Klaus Bosselmann, director of the New Zealand centre for environmental law at the University of Auckland, was an observer at the climate negotiations in Paris.