The IPCC Assessment Report Explained

The Origin of the IPCC

What is often regarded as the world’s largest peer-reviewed process, has only been in operation for 35 years. In 1988, the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) established the Intergovernmental Panel on Climate Change (IPCC). In the last 35 years of its operation, the IPCC has been tasked with the responsibility of assembling reviews and recommendations regarding the science of climate change, its social and economic impacts, as well as possible responses to climate change. 

While the work of the IPCC can be attributed to many scientists, the panel is the result of 197 governments that sought more information on the state of the global climate. The IPCC released its first report in 1990 with the help of 250 scientists. Since its debut report the contributing community has grown significantly.

Today, there are thousands of dedicated scientists within the IPCC who volunteer their time and expertise to the IPCC by authoring and reviewing work published by the organization. The panel is composed of three working groups and one task force.

Working Group I focuses on The Physical Science Basis of Climate Change and Working Group II focuses on Climate Change Impacts, Adaptation and Vulnerability. Meanwhile, Working Group III handles Mitigation of Climate Change. All three working groups create separate assessments on the climate that are released every 6-7 years. At the end of the cycle, the groups publish their separate reports that together make up the IPCC Assessment Report.

The Sixth Assessment Cycle

The Sixth Assessment Report (AR6) is the latest report published by the IPCC and given its separate contributions by the three Working Groups, each segment  was released at a different time. The entire report was available to the public in April 2022 and seven months later the Synthesis Report was published to summarize the findings within all three components of the Sixth Assessment Report. By evaluating the climate, its impacts, and mitigation options, the AR6 serves as a resource for global climate negotiations and policymaking.

Responsibilities of AR6 Working Group I

Working Group I (WGI) assesses the physical scientific basis of the climate system and climate change. This is done by evaluating Earth’s climate in past, present, and future contexts. WGI focuses on topics such as greenhouse gasses and aerosols in the atmosphere; temperature changes, precipitation patterns, sea levels, the carbon cycle, and climate sensitivity. Essentially, WGI studies the science behind our climate and how humans are impacting it.

When the IPCC releases its synthesis report, each working group publishes a report that specifically addresses its focal topic. As such, the report published by WGI covers the most up-to-date understanding of the Earth’s climate system. A total of 234 authors from 64 countries contributed to the most recent report and met on several occasions in the years leading up to its publication. In the 2021 report, WGI examines the role of human influence on climate change and its knowledge on the climate future.

Responsibilities of AR6 Working Group II

Working Group II (WGII) examines the impacts, adaptations, and vulnerability as related to climate change. More specifically, WGII looks at how climate affects the vulnerability of socio-economic and natural systems. Both positive and negative consequences are considered and options are explored to adapt to these impacts. The reports published by Working Group II analyzes how society and Earth’s ecosystems will be impacted by extreme climate conditions. The consequences of climate are evaluated at the global and regional level. Two co-chairs and eight vice-chairs lead WGII with help from a Technical Support Unit located in Germany and South Africa.

Responsibilities of AR6 Working Group III

Working Group III (WGIII) dives into options for climate change mitigation. The group studies how greenhouse gas emissions may either be limited or prevented altogether. Climate mitigation involves any action that can slow  climate change by reducing the rate of greenhouse gas emissions. Because of this, there are multiple technologies and methods to address climate change that Working Group III must analyze to assess the effectiveness of reducing emissions. GHG emissions can originate from several sources like agriculture, industry, forestry, transportation, and waste management. WGIII can be regarded as the solution-oriented group in the IPCC. It’s their responsibility to explore all possible options for addressing and solving the climate crisis.

With the multiple possible methods for climate mitigation, WGIII must take a neutral stance and conduct an unbiased assessment of each without promoting any one method. The evaluation covers “technical feasibility, cost, and the enabling environments that would allow measures to be taken up.” There are two co-chairs, Jim Skea and PR Shukla, and seven vice-chairs.

BECCS as Mentioned in Working Group III

Within the existing 6th assessment report, WGIII has provided its findings on Bioenergy with Carbon Capture and Storage (BECCS) and its potential for climate mitigation. 

The technology used for BECCS has been utilized for over 50 years and the most recent WGIII report found carbon removal with BECCS should scale to between 30-780 billion tonnes globally within the century to remain below the 1.5° climate target. 

It has also determined the approximate storage capacity with BECCS.“The technical geological CO2 storage capacity is estimated to be on the order of 1000 GtCO2, which is more than the CO2 storage requirements through 2100 to limit global warming to 1.5°C.”

With this in consideration, BECCS at scale will have ample capacity to store CO2. Once CO2 is stored in geological reservoirs via BECCS, carbon is locked away permanently on geologic timescales,  in comparison to carbon removal methods through vegetation and soil management, both of which can be undone by human or natural disturbances.

Why the IPCC Matters

Since the initial launch of the IPCC, the panel has released six assessment reports. All of which are highly anticipated, being that the reports help inform policy making on an international level. The IPCC has the credibility and influence to determine how the world responds to climate change. The research conducted by each Working Group informs the world’s leaders and governments, which determines how communities across the globe can better prepare for and adapt to expected changes in the Earth’s climate.