All about the IPCC report on climate change

On October 8, 2018, the IPCC (Intergovernmental Panel on Climate Change) published its special report entitled "Global Warming of 1.5°C". This 400-page report, which was based on 6,000 studies, was commissioned by the governments during the Paris negotiations on the climate in 2015. It was released ahead of COP24 in Katowice, Poland, in December 2018.

A report in response to the COP21 goals

In December 2015, the signing of the Paris Agreement (COP21) made it possible to set the objective of limiting the global rise in land temperatures to 2°C by 2100, and even to 1.5°C if possible. It is in light of this ambitious goal that the IPCC has published this new report. The report examines the steps that must be taken to successfully limit the rise in global temperature this century to 1.5°C.

COP21 (December 2015)

191 States have committed to public policies to limit the rise in temperatures by 2100:

to below 2°C,
by achieving net zero greenhouse gas emissions.

We need to act urgently

The IPCC experts estimate that global warming of 1.5°C will be reached sooner than expected, between 2030 and 2052. The challenge is therefore to contain this rise, or reverse it if it is exceeded, to ensure that the global temperature does not increase even further by 2100.
The report highlights the many positive impacts of achieving this goal of 1.5°C compared to 2°C:

by 2100, sea level rise would be 10 cm lower,
the likelihood of a sea ice-free Arctic Ocean would only be one per century, as opposed to at least one per decade,
coral reefs would decline by 70 to 90% with a temperature rise of 1.5°C, in comparison to a loss of 99% otherwise.

"One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes."
Panmao Zhai, Co-Chair of IPCC Working Group I

In practice, the IPCC has performed two different analyses. The first involves the formulation of four model pathways that would limit the global temperature rise to 1.5°C by 2100. The second is based on a review of the 85 pathways scientifically identified by the IPCC that would make it possible to achieve this objective.

All the IPCC scenarios require more nuclear power

The four pathways (P1-P4) examined by the IPCC show the importance of studying different societal approaches. Pathway P3 in particular is based on the continuation of technological and societal development as observed historically. The use of nuclear power increases in all four pathways in relation to 2010, by between 59 and 106% by 2030 and by between 98 and 501% by 2050. Pathway P3 also shows the most notable rise in nuclear generation (+501%) by 2050. This means that, if current trends continue, compliance with climate objectives will require a six-fold increase in global nuclear capabilities.

Lastly, it should be noted that the four IPCC model pathways lead to negative emissions from 2050.

To achieve the goal of limiting the temperature rise to 1.5°C by 2100, the four IPCC model pathways conclude that nuclear generation must increase by:
+59-106% by 2030
+98-501% by 2050
+501% by 2050 for pathway P3

"If current trends continue, compliance with climate objectives will require a six-fold increase in global nuclear capabilities."

Analysis of the scientific scenarios

The IPCC has also studied 85 pathways that would limit global warming to 1.5°C by 2100. The median value for nuclear generation more than doubles between 2020 and 2050 (increasing from 10.84 EJ* to 22.64 EJ*) in these scenarios. Its share in the global energy mix remains significant, at almost 9% in 2050.

To achieve the goal of limiting the temperature rise to 1.5°C by 2100, the study of 85 scientific pathways concludes that nuclear power generation must more than double between 2020 and 2050: 10.84 EJ* to 22.64 EJ*
*1 EJ (exajoule) = 1018 J
The IPCC specifies, in relation to its analysis, that "there are large differences in nuclear power between models and across pathways. One of the reasons for this variation is that the future deployment of nuclear can be constrained by societal preferences assumed in narratives underlying the pathways."

IPCC observations regarding nuclear power

In its report, the IPCC recalls that "in the 1960s and 1970s, France implemented a programme to rapidly get 80% of its power from nuclear in about 25 years, but the current time lag between the decision date and the commissioning of plants is observed to be 10-19 years".

The report also specifies that the current deployment pace of nuclear energy is "constrained by social acceptability in many countries" due to concerns regarding the risk of accidents and radioactive waste management.

"Though comparative risk assessment shows health risks are low per unit of electricity production, and land requirement is lower than that of other power sources, the political processes triggered by societal concerns depend on the country-specific means of managing the political debates around technological choices and their environmental impacts," adds the IPCC report.