The core logic of these agreements is captured in the introductory text of the Trans-Pacific Partnership (TPP): "to establish a predictable legal and commercial framework for trade and investment ..." In these agreements, the right of investors to a light-handed, "business as usual" regulatory environment is paramount. Considerations like climate change, health and human rights are given either low priority or ignored altogether.
In more than 6000 pages of legal text in the TPP, climate change is not mentioned once. On the other hand, entire chapters are devoted to minimising "technical barriers to trade" and ensuring "regulatory coherence". These chapters consist of a range of rules that would turn the move to zero carbon into a legal minefield.
In addition, investors such as fossil fuel companies would be given broad powers to directly sue governments in off-shore tribunals for unfavourable changes in policy under investor-state dispute settlement provisions.
Awarding these powers to the fossil fuel industry is a direct affront to the Paris agreement. Given that trillions of dollars' worth of fossil fuel reserves must remain in the ground - investor-state dispute settlement clauses are a disaster waiting to happen.
Even now, their threat is very real. In Germany, changes to coal-fired power plant standards evoked a US$1.5 billion case initiated by an energy company claiming a violation of their right to "fair and equitable treatment".
Similarly, in Canada, a moratorium on hydraulic fracturing (fracking) under a major river brought a US$120 million case from a US oil and gas firm based on the claim that it violated their "legitimate expectation of a stable business and legal environment".
Despite New Zealanders being assured there would be safeguards against these provisions in the TPPA the final text reveals these are marginal at best. Ratifying the agreement would therefore spring-load the investor-state dispute settlement enforcement mechanism.
Powerful, polluting multinationals would become poised and ready to launch claims the moment we begin to get serious about reducing our emissions.
The NZ climate change ambassador has dismissed the idea that the TPPA would obstruct future action on climate change. However, this view is directly at odds with the European Union Parliament that recently proposed a specific legal "carve out" in a similar investment agreement, aiming to ensure that investors would not be able to sue governments for policies designed to reduce carbon emissions.
The Paris agreement carries symbolic power and is a small pivot towards a stable and health-sustaining climate, but its legal force must be interpreted alongside parallel international agreements that are expressly designed to lock the steering wheel on reforms. If ratified, agreements with strong enforcement mechanisms such as the TPPA could effectively trump the weakly binding Paris agreement. It should be the other way around.
• Dr Joshua Freeman is a consultant clinical microbiologist and an executive member of OraTaiao, the NZ Climate and Health Council.
• Dr Hayley Bennet is a public health medicine specialist and national co-ordinator for OraTaiao.