IPCC to release the Synthesis Report of its Fifth Assessment

The Intergovernmental Panel on Climate Change (IPCC) prepares to finalize the last piece of its Fifth Assessment Report (AR5) cycle, a full update of the state of knowledge on climate change from the previous Assessment Report released in 2007.

The Synthesis Report (codename: SYR) is going to be considered from 27 to 31 of October in Copenhagen, and made public on the 2 November. It integrates key messages from the three recent working group reports: the physical science basis (WGI, released in September 2013), impacts, adaptation, and vulnerability (WGII, released in March 2014), and mitigation of climate change (WGIII, released in April 2014).

Participating governments in consultation with the authors are going to adopt the document through a “section-by-section” discussion, while the Summary for Policymakers will be approved line-by-line within the IPCC’s endorsment procedures. The process guarantees that the Assessment Report is acknowledged as a shared result bewteen “those who will use the report – the governments – and those who write it – the scientists”.

The AR5 final release takes on additional importance as it will come just before the COP20 international conference, opening on the 1st of December in Lima, where global leaders will discuss the foundation of a new climate deal expected in 2015.

“This Synthesis Report, integrating the findings of the three working group contributions to the IPCC’s Fifth Assessment Report and two special reports, will provide policymakers with a scientific foundation to tackle the challenge of climate change. It would help governments and other stakeholders work together at various levels, including a new international agreement to limit climate change,” said IPCC Chairman Rajendra K. Pachauri in an official statement (pdf).

Here a summary of the three working groups’ contribuitions to AR5:

Working Group I reports on the physical science of climate change. The WGI contribution states that there is a 95 percent probability that human activity has been the dominant driver of warming since the mid-20th century. The report elaborates on evaluations of climate science research into atmospheric and ocean changes, sea-level rise, climate drivers, GHG concentrations and new future scenarios.

Working Group II considers the vulnerability and exposure of human and natural systems to climate change. Their contribution to AR5 reports the risk of death and disrupted livelihoods caused by sea level rise and coast inundation, food security, flooding in urban areas, insufficient access to drinking and irrigation water, loss of terrestrial and marine ecosystems, disease and death due to extreme heat, and it gives insight on adaptation measures and options.

Working Group III assesses mitigation policies and technologies. WGIII established that global GHG emissions must be reduced by 40-70 percent compared with 2010 levels by 2050 to limit the increase in global mean temperature to 2°C. There are a wide array of technological measures and behaviour changes available to achieve this. Economic mitigation costs are estimated at 0.06 percent of annual consumption growth over the 21st century. This mitigation effort must come from all sectors and cannot be effective if individual agents seek to advance their own interests.


(Photo credit: IPCC/Flickr)