The first part of this article outlines everything you need to know about the IPCC and its reports (if you didn’t already know it)! The second part of this article provides a 101 summary of the latest IPCC reporting cycle (AR6), highlighting key findings from working group reports.

---

The IPCC & IPCC Reports

The Intergovernmental Panel on Climate Change (IPCC) is the United Nations body for assessing the science related to climate change.

Created in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP), the IPCC provides governments at all levels with scientific information for developing climate policies. This information is derived through regular scientific assessments of the basis of climate change, its risks and impacts as well as potential action for mitigation and adaptation. The IPCC is composed of members of the United Nations or WMO; currently the IPCC has 195 members.

As deadly serious as the IPCC sounds (and is), it is truly inspiring to watch scientists, policymakers and experts from all across the world come together to improve our understanding of the physical world, outlining clear priorities and actions that must be taken to safeguard our future on Earth. With hundreds of authors contributing to each report, repeatedly scoping, reviewing and revising the report to forward the climate agenda; the effort is simply mind-blowing! Read more about the IPCC here.

The IPCC is currently in its 6th cycle of Assessment Report (AR) with the first report dating back to 1990. Several reports are produced in each AR cycle, one by each designated ‘working group’ (WG) made up of scientists from across the world. Reports often build on previous assessments and reports to frame a more updated and complete picture of climate change knowledge.

As the full reports produced by each WG can be very lengthy (thousands of pages long!), the reports are published in several forms to capture the attention of both broader and targeted communities (in order of easiest to most challenging reads):

1. Headline Statements – overview of key findings (only 2-3 pages!)
2. Summary for Policymakers (SPM) – shorter, less technical version of the full report (30-40 pages)
3. Full Report – the full WG report (between 2000-4000 pages!)
4. Technical Summary (TS) – for further scientific detail (close to 100 pages in addition to the full report; often links findings across reports and reporting cycles)

The Assessment Report comprises not only the WG reports and a final synthesis report (which wraps up the key findings of the WG reports), but also additional ‘Special Reports’ prepared in that assessment cycle. Read more on the AR structure here.

---

IPCC 6th Assessment Report (AR6)

The 6th Assessment Report has three working groups, each producing one report. These three reports are followed by the AR6 Synthesis Report. Below is a summary of each WG report with links for further reading:

Working Group I – AR6 Climate Change 2021: The Physical Science Basis

Published: August 2021

Summary: Provides the latest scientific understanding of climate change by examining the physical science of the past, present and future. Includes possible climate futures through scenarios, climate models and projections; details of known and unknown factors key to interpreting our current knowledge of climate science.

Some key takeaway points:

• Unequivocal that human influence has warmed the ocean, land and atmosphere; climate change is human induced.
• Evidence of observed changes in extremes (such as heatwaves, heavy precipitation , droughts and tropical cyclones) linked to human influence has strengthened since the Fifth Assessment Report (AR5).
• Continued global warming is projected to exceed 1.5C and 2C warming by the end of the 21st century (year 2100) unless deep reductions in carbon dioxide and other greenhouse gasses are made in coming decades.
• Found a 1.09C increase in global surface temperature in 2011-2020 from 1850-1900. This estimated increase is due to further global warming since 2003-2012.  
• Considering all scenarios assessed, there is at least a 50% chance that global warming will exceed 1.5C warming in the near-team (by 2040).
• Limiting human-induced global warming (to a specific level) requires reaching at least net zero carbon dioxide emissions, along with strong reductions in other greenhouse gas emissions.

Read more: AR6 WG I Headline Statements

Working Group II – AR6 Climate Change 2022: Impacts, Adaptations and Vulnerability

Published: February 2022 

Summary: Reviews the impacts of climate change on ecosystems, biodiversity and human communities at regional and global scales. Also reviews in detail the vulnerabilities, capacities and natural limits of Earth and human societies to adapt to climate change. 

Some key takeaway points:

• Vulnerability of ecosystems and people to climate change differs substantially among and within regions, driven by patterns of intersecting socio-economic development, unsustainable ocean and land use, inequity, marginalization, historical and ongoing patterns of inequity such as colonialism, and governance. 
• Approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change. A high proportion of species is vulnerable to climate change; human and ecosystem vulnerability are interdependent.
• Some development and adaptation efforts have reduced vulnerability, though across sectors and regions, the most vulnerable people and systems are disproportionately affected.
• Safeguarding biodiversity and ecosystems is fundamental to climate resilient development, in light of the threats climate change poses to them and their roles in adaptation and mitigation
• It is unequivocal that climate change has already disrupted human and natural systems. Societal choices and actions implemented in the next decade determine the extent to which medium- and long-term pathways will deliver higher or lower climate resilient development.

Read more: AR6 WG II Headline Statements

A snapshot of the report’s findings at regional levels is provided here: Fact Sheets

Working Group III – Climate Change 2022: Mitigation of Climate Change

Published: April 2022 

Summary: Examines global emission sources and details developments in emission reduction and mitigation efforts. Provides an update on national climate change pledges and its impact on long-term emission goals.

Some key takeaway points:

• Average annual GHG emissions during 2010-2019 were higher than in any previous decade, but the rate of growth of GHG emissions between 2010 and 2019 was lower than that between 2000 and 2009.
• The 10% of households with the highest per capita emissions contribute a disproportionately large share of global household GHG emissions. At least 18 countries have sustained GHG emission reductions for longer than 10 years.
• Global GHG emissions in 2030 associated with the implementation of nationally determined contributions (NDCs) announced prior to COP26 would make it likely that warming will exceed 1.5°C during the 21st century. Limiting warming to below 2°C would then rely on a rapid acceleration of mitigation efforts after 2030. 
• Global GHG emissions are projected to peak between 2020 and 2025 in global modeled pathways that limit warming to 1.5°C (with no or limited overshoot) and in those that limit warming to 2°C. These models assume immediate action.
• Global net zero CO2 emissions are reached in the early 2050s in modeled pathways that limit warming to 1.5°C with no or limited overshoot, and around the early 2070s in modeled pathways that limit warming to 2°C. Many of these pathways continue to net negative CO2 emissions after the point of net zero.
• Many regulatory and economic instruments have already been deployed successfully.There are mitigation options which are feasible to deploy at scale in the near term (by 2040). International cooperation is a critical enabler for achieving ambitious climate change mitigation goals.

Read more: AR6 WG III Headline Statements

AR6 Synthesis Report – Synthesis Report of the Sixth Assessment Report

To be published: September 2022

Interpreting and Appreciating AR6

The AR6 is an impressive body of work that is instrumental to guiding and driving global climate action. As with any piece of scientific research, there are certain assumptions, caveats and limitations to the findings of the work, which have been clearly highlighted throughout the reports (e.g., careful phrasing of sentences and use of confidence levels). While our understanding of the world is ever-changing and growing, these reports represent mankind’s best effort to unravel, analyze and overcome the complex challenges and implications of climate change as we know it. 

This article is based on the IPCC 6th Assessment Reports. All information and figures cited in this article can be found through the in-text links provided. Cover image sourced from the Royal Society.

---