Turning up the heat: how the diplomatic push for 1.5℃ unfolded in Paris

The inclusion of a 1.5℃ temperature limit in the new Paris climate agreement was a major victory for the poorest countries and island nations who came to Paris saying they wanted the world to act.

By placing the 1.5℃ limit alongside the legally binding goal to hold global temperatures “well below 2℃ above pre-industrial levels”, the deal offered hope to the many who had begun to despair about the prospects of an ambitious enough global climate agreement ever being reached.

As an adviser to the government of one of these vulnerable countries – St Lucia – I had the privilege of being at the epicentre of the Paris Agreement negotiations.

The inclusion of 1.5℃ surprised many governments and well-placed observers, given that in the run-up to the summit, preparations seemed fixed only on securing a 2℃ limit. But in truth, the scientific and diplomatic push for a stronger agreement had been going on for years, if not decades.

Backing the science

The formal 1.5℃ target is based on progressive improvements over 25 years in the science of understanding of the risks of climate change, and on the economics and technology of cutting greenhouse emissions. This huge body of work has now been translated into an international law that seeks to put a safe “speed limit” on the global climate.

For much of the time, the world was considering what has come to be seen as a more dangerous speed limit. The 2℃ goal emerged from the European Union in 1996 after ministers considered the outcome of the Intergovernmental Panel on Climate Change’s 1995 Second Assessment Report, and it was ultimately enshrined in the 2009 Copenhagen Accord. But this ignored the fact that by 2009, more than 100 vulnerable countries, alarmed about the projected impacts for 2℃ described in the IPCC’s Fourth Assessment Report – not to mention the impacts they were already beginning to see and feel – had already begun calling for an alternative 1.5℃ limit.

Taking the target to Paris

In Paris, despite the objections (from Saudi Arabia in particular), many more governments beyond the small islands and least developed countries began to join the call for 1.5°C to be included in the purpose of the agreement. By halfway through the summit, some 114 governments had backed the new, more ambitious target.

The reaction of negotiators from many of the big countries and groupings was one of surprise and, in some cases, shock that this issue had even come up. It shouldn’t have been that shocking really – the small island states and least-developed countries had been prominently inserting this goal into the draft text ever since the pre-Paris negotiations began, back in Durban in 2011. Yet negotiators from many of the big groups pushed back.

Nor could the scientific recognition that 2℃ was no longer a safe “guardrail” have been a surprise, given that a UNFCCC report had already reached this conclusion back in June. Yet, still the bigger emitters expressed surprise and shock at the idea of the purpose of the agreement reflecting the 1.5°C limit.

It quickly became clear to anyone paying attention that the inclusion of 1.5℃ in the agreement was a “red line” for many countries. Barbados' environment minister Denis Lowe expressed it in almost Shakespearean terms, saying that he had not come to Paris seeking a sympathy vote – and that failing to include 1.5℃ in a meaningful, non-token way would be tantamount to a rejection of his people’s right to exist.

Barbados: too nice to lose. Veronidae/Wikimedia Commons, CC BY-SA

Country after country argued that they were already feeling the heat with 1℃ warming to date, and that by 1.5℃ they would be suffering extreme damage and risk, and that even this target would represent a significant compromise.

Luckily, the French organisers of the summit had been paying attention. They knew they would have to find a meaningful way to accommodate the 1.5℃ goal if they wanted to have any hope of clinching an agreement.

A difficult challenge

Of course the Paris Agreement is much more than the 1.5℃ limit, but the limit is a fundamental guide to how the agreement should be implemented, and a signal of the urgency with which nations must address climate change.

To limit warming below 1.5℃ by 2100, the best available science indicates that the world needs to reach zero greenhouse emissions between 2060 and 2080, or between 2080 and 2100 for a 2℃ limit. These time frames are now written into the long-term goal in Article 4 of the agreement, which commits countries collectively to reach zero global greenhouse emissions in the second half of the century.

The rate of global reductions, and hence the time at which zero global emissions are achieved, are to be “in accordance” with the best available science, an obvious, but hard-fought clause to ensure that regular scientific assessments play a role in defining when and how zero emissions need to be achieved.

Some observers and governments were concerned that the inclusion of a temperature limit could obstruct inclusion in the agreement of a time frame for deep 2050 emission reductions and for reaching zero emissions. From where I sat, it is hard to see how this could ever have been achieved without there being a temperature goal in the purpose of the agreement, as otherwise there are many parties who would have argued that there was no basis for setting any particular time frame.

Many would have preferred a reference to “decarbonisation” in the long-term goal, even at the expense of the temperature goal. However, there was deep opposition to this term, particularly among oil-exporting countries. Indeed, this allergy extended to nearly any term that mentioned the word “carbon”.

Five-yearly ambition cycle is critical

Some have expressed concerns that the Paris Agreement does not contain a concrete roadmap for how the necessary emission reductions will be achieved, and how effort is to be shared between countries with very different levels of economic development. But how could it, beyond prescribing the five-yearly reviews that will push each country to strengthen its ambition?

There are those who have questioned, or even denied, the feasibility of limiting warming to 2℃, let alone 1.5℃. But these are more expressions of personal political judgements rather than a description of what the science tells us is possible. One is entitled to be pessimistic about whether politicians will take the action needed to limit warming below 2℃, given the lack of progress to date. However, such pessimism is not a scientific opinion and should never be dressed up as such.

The Paris Agreement is historic and it should be no surprise that the challenges ahead in achieving its purpose will dominate the 21st century – as would its failure due to the damages, impacts, ecological and human dislocation that would be caused by just a few degrees of warming. The initial climate pledges submitted by governments are far from sufficient: without rapid improvement we are indeed heading for around 3℃ of warming.

The hard-fought ambition mechanism in the agreement establishes a common five-year global political moment, starting in 2020. If used effectively this will create the sustained political pressure to progressively improve each country’s climate pledges, gradually winding back global emissions towards zero on a time frame consistent with the the 1.5℃ limit.

No one, however, should underestimate the gravity and scale of the task ahead. The Paris deal has set the rules and fired the starting gun in the race to save the planet from climate change. How we run that race is now up to us.