Plan A was a global treaty that would limit emissions of greenhouse gases (GHGs) to acceptable levels in line with our scientific understanding. A collective limit or budget might then have been divided equitably between countries. Developed countries would help finance developing countries in their adaptation plans and transitions to clean technologies.

A similar approach had been used successfully to reduce the chlorofluorocarbons (CFCs) that were, until the 1980s, the mainstay of refrigeration, but which were causing fatal damage to the ozone layer.

The UN Framework Convention on Climate Change (UNFCCC) was agreed in 1992 and entered into force in 1994. It has 197 Parties. Its objective is set out in Article 2, as follows:

‘The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve … stabilization of greenhouse gas

concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

However in the 22 years that have followed global GHG emissions have continued to rise at an accelerating rate. The 1997 Kyoto Protocol set binding limits for developed Country Parties, but was not ratified by the US and did not set limits for developing countries. In 2009 in Copenhagen political divisions between Parties appeared so intractable, and the outcome so unsatisfactory, that the UNFCCC process was in danger of implosion.  From that low ebb the 2015 Paris Agreement can be considered a diplomatic triumph.

The success, however, has come at a price:

  • The Ultimate UNFCCC Objective is not mentioned, let alone quantified;
  • A global carbon-budget is not mentioned, let alone quantified;
  • So the Agreement provides no clear foundation even for a discussion of international budget-sharing arrangements;
  • Collectively the Nationally Determined Commitments (NDCs) declared are too little too late to achieve the objective;
  • It is not possible to relate NDCs to future temperature change until ‘after the fact’, by which time we will have become circumstantially locked into the ‘too little too late’ scenario (as already augured in projections for the aggregated impact of present NDCs).

As it stands, the political process under the UNFCCC leaves the planet on course for warming of 3 to 4 degrees Celsius, an outcome that would pose an unprecedented threat to human civilisation and life on earth. It is misleading to describe such an outcome as a triumph.

However UNFCCC and the Paris Agreement must be interpreted in light of the general principles of international law that demand a science-based, equitable approach to the use of natural resources (including the atmosphere and the oceans). The weaknesses of the Paris Agreement can and should be addressed through the courts.

The clock is ticking: it is time for Plan B