Understanding the history of the 1.5°C target: From "science first" to "politics first"

Since its beginnings in the 1980s and 1990s, science has played a crucial role in defining the climate question. Similarly, climate policy has always been inherently “scientized”. But the times, they are a'changing.


By Monica Bjermeland


From 1988 onwards, the Intergovernmental Panel on Climate Change (IPCC) has orchestrated consensus through its various enormous reports of climate science.

1988 is also the year when NASA scientist James E. Hanson held his famous speech to the US Senate, proclaiming that global warming had begun.

What many may have forgotten, is that President Gayoom of the Maldives gave a similar speech to the UN, about the threat of sea-level rise due to climate change, already the year before; in 1987.

Man's action over many centuries have transmuted the natural order of his environment to the point where the whole world is ensnared in the consequences. PRESIDENT MAUMOON ABDUL GAYOOM, 1987

Gayoom’s call to arms came from a concern for the “front line states” of climate change; the small island developing states. The Pacific with its thousands of islands is highly dependent on the ocean and its resources for basic survival – severe storm surges and flooding have threatened its peoples and societies for over 30 years, a situation getting worse by the day.

Today, this grim reality also concerns less vulnerable areas. Rememember the extreme temperatures we had this summer? Hurricane Florence? Tyfone Mangkhut?

Scientific consensus does not trigger sufficient climate action. Old news, for sure, but nevertheless still relevant. Most of us agree that climate change is real, science has us convinced, and yet political action does not follow. This dire insight is partly what led to the establishment of a temperature target in the UN climate summit in Copenhagen in 2009, often referred to as the “failure summit”.

A move of power is underway and this was becoming clear already in 2009. Policy was beginning to inform science, rather than the other way around.

In a book chapter in Globalising the Climate (2018), science writer cum climate scholar Hèléne Guillemot, shows how even temperature targets themselves have gone from being science-driven, as the 2°C target, stemming from Copenhagen, to being policy-driven, as the current 1.5°C target established in Paris in 2015 arguably is.

As a quick reminder, Article 2 in the Paris Agreement sets out to

(hold) the increase in the global temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change

Does it follow, then, that 1.5°C is an “evidence-based” climate objective?

Climate scientists themselves are reluctant to temperature goals. In 2009, “a survey by the British newspaper The Guardian showed that 85% of climate scientists did not believe it would be possible to limit warming to 2°.”

Guillemot sees the emergence of the even more ambitious 1.5° target in 2015 and the resulting strengthening of disagreements among scientists as a further politicization of the climate domain.

“While this mention of a 1.5°C target in the agreement was almost unanimously welcomed by state delegations and NGOs”, writes Guillemot in “The necessary and inaccessible 1.5°C objective”, “initially it surprised, and even shocked, many climate scientists”.

Even so, climate scientists have now been asked to make sense of it by way of research. In early October, a report summarizing research on the 1.5° target is to be published in South Korea by the IPCC. A leaked draft of this major UN report – the most important climate science report of 2018 – shows growing certainty that even 2°C, recently shorthand for a ‘safe’ amount of planetary warming, would be a dangerous step for humanity, and - as always - particularly dangerous for the most vulnerable among us.

The making of this special report is controversial. According to Guillemot, the climate science community has faced a threefold challenge in producing it: “first, there are few studies on the 1.5°C target and the deadline very tight to produce more; second, the 1.5°C target has major diplomatic implications, so the report will be subjected to scrupulous political examination by all parties; and thirdly and above all, many researchers find working on the 1.5°C target problematic.”

This move from “science first” to “politics first” in international climate governance has issued more power to the world's most vulnerable people and places.

Moreover, based on the 104 countries who have ratified the Paris Agreement - and their nationally determined contributions - we are, in fact, on a 90 percent certain track to exceed even 2°C by 2100.

So, although the placing of a 1.5°C ambition is a major victory for vulnerable countries who have worked hard for more aggressive climate ambitions since the 1980s, heavy vested interests are still stalling climate action.

Climate researchers, Guillemot concludes, faces an unprecedented task of having to produce a report on a target they know is unattainable, to satisfy a political agenda.

On a more positive note, this move from “science first” to “politics first” in international climate governance has already issued more power to the world's most vulnerable people and places. In the Paris Agreement, human rights language entered climate change discourse.

Driving this power balance shift stand people whose existence is already ruthlessly under threat; indigenous peoples who own little land but who maintain 80 percent of the planet’s biodiversity; people from small island states being driven from their homes today, in a one-degree warmer world.

As the voices below reveal, evidence-based policy-making in the field of climate change is not so straightforward as it may seem. 


Two hundred countries are now under mounting pressure to finalize the Paris Agreement's Rulebook. The priority of climate scientists cannot longer be, as Guillemot argues, to inform the negotiators of these countries and the wider public "on the scope of the problem but to respond to a more diverse and fragmented set of scientific and political questions.”

Willingly, we let certain countries in our common world go extinct. How can we?

In this article, you will find a portrait of the hailed but inefficient 1.5°C target from Paris, interviews with its most eager proponents, and a commentary on the shift in global climate governance from science to politics.
The 1.5°C target’s rise to fame is built on years of careful groundwork by people who share a profound precarity to the adverse effects of climate change.

This story is their – soon to be our – story.
— Monica Bjermeland