The Intergovernmental Panel on Climate Change (IPCC)

The Intergovernmental Panel on Climate Change (IPCC) is charged with assessing the most up to date scientific, technical and socio-economic research on climate change.

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Introduction

The IPCC provides regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation. Its primary objective is to provide governments at all levels with scientific information that they can use to develop climate policies. IPCC reports are therefore a key input into international climate change negotiations. IPCC reports are also used by a variety of other users, e.g. researchers, students, schools, businesses, non-governmental organizations, and the general public.

Sixth Assessment Report (2021 and 2022)

The IPCC’s Sixth Assessment Report (AR6) is being released in stages between August 2021 and September 2022.

Working group I: Climate Change 2021: The Physical Science Basis

In August 2021 the IPCC released the first part of the Sixth Assessment Report, Climate Change 2021: The Physical Science Basis, the Working Group I contribution to the Sixth Assessment Report.

Watch the video trailer for this report:
IPCC Sixth Assessment Report - Climate Change 2021: The Physical Science Basis (Trailer)
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Depending how much detail you need, the IPCC offers the report distilled into Headline Statements, a Summary for Policymakers and a Technical Summary. It is also available on the IPCC website in full (~1300 pages). 

Key findings from AR6 Working Group I

As with previous reports, the key message in this report is that widespread and rapid changes in the global climate system are due to human influence. The planet has warmed 1.1°C since 1850 and anthropogenic greenhouse gas emissions are the leading cause. 

Human influence has warmed the climate at a rate that is unprecedented in at least the last 2000 years (image credit: IPCC SPM.1):

Credit: IPCC

The report sets out a series of possible future scenarios, called Shared Socioeconomic Pathways – narratives that describe broad socioeconomic trends linked to differing greenhouse gas emissions. In contrast, the IPCC Fifth Assessment Report described Representative Concentration Pathways, or RCPs (you might like to read this explainer to understand the difference). 

The AR6 Working Group I report shows that future emissions will cause future additional warming, with total warming dominated by past and future CO2 emissions (image credit: IPCC SPM.10):

The report states that human activities affect all the major climate system components, with some responding over decades and others over centuries – including global surface temperature, changes in extreme weather (e.g. heavy rain and droughts), Arctic sea ice depletion, sea level and ocean acidity. 

For a visual summary of the report including the above impacts and relevant graphics, you may wish to download the slide pack for IPCC AR6 Working Group I: The Physical Science Basis.

Working Group II: Impacts, Adaptation and Vulnerability (February 2022)

This report covers:

  • Co-benefits, risks and co-costs of mitigation and adaptation, including interactions and trade-offs, technological and financial challenges and options.
  • Ethics and equity: climate change, sustainable development, gender, poverty eradication, livelihoods, and food security.
  • Perception of risks and benefits of climate change, adaptation and mitigation options, and societal responses, including psychological and sociological aspects.
  • Climate engineering, greenhouse gas removal, and associated feedbacks and impacts.
  • Regional and sectorial climate information.
  • Epistemology and different forms of climate related knowledge and data, including indigenous and practice-based knowledge.

Working Group III: Climate Change 2022: Mitigation of Climate Change (March 2022)

This report covers:

  • Socio-economic scenarios, modelling and transitions at the global, regional, national and local scales including integrated assessment approaches.
  • Energy systems including supply and energy demand sectors (e.g., industry, transport, buildings). Mitigation responses in agriculture, forestry, land use and waste.
  • Consumption patterns, human behaviour and greenhouse gas emissions, including economic, psychological, sociological and cultural aspects.
  • Policies, agreements and instruments at the international, national and subnational levels, including those at the city level.
  • Technology innovation, transfer and deployment.
  • Financial aspects of response options.

AR6 Synthesis Report (due September 2022)

Publication of the AR6 Synthesis Report will be the last stage in the IPCC’s Sixth Assessment cycle. It will follow publication of the three Working Group reports, as well as three Special Reports and a refinement to the IPCC methodology report.

The AR6 Synthesis Report will “synthesise and integrate materials contained within the Assessment Reports and Special Reports” and “should be written in a non-technical style suitable for policymakers and address a broad range of policy-relevant but policy-neutral questions approved by the Panel”. 

Fifth Assessment Report

The IPCC’s Fifth Assessment Report (AR5) was released in stages over 2013 and 2014, culminating in the AR5 Synthesis Report: Climate Change 2014. 

Special reports

In addition to its full Assessment Reports, the IPCC regularly releases technical papers, special reports and methodology reports (e.g. standard methodologies for national greenhouse gas emission inventories) for use by Parties to the United Nations Framework Convention on Climate Change.

Upcoming and recent special reports include:

About the IPCC

The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). It is charged with assessing the most up-to-date scientific, technical and socioeconomic research on climate change. IPCC reports synthesise evidence and analyses published either in peer-reviewed journals or other credible sources.

Approximately once every six years since 1988, the IPCC produces a full assessment of the current state of scientific knowledge on climate change and what it means for us. These major assessment reports have been published in 1990, 1995, 2001, 2007, 2013 and, most recently, the first part of the Sixth Assessment Report was released in August 2021 (see above). 

The IPCC has developed procedures for the preparation, review and approval of its assessment reports aimed at guarding their objectivity and ensuring all relevant information is considered. Report preparation and review involves large numbers of experts from most countries of the world.

New Zealand and NIWA participation

New Zealand participates actively in the IPCC. University and Crown Research Institute scientists routinely contribute as authors and reviewers of Assessment Reports, Special Reports and Methodological Guidelines. 

NIWA’s Dr Olaf Morgenstern was a lead author of chapter 3 of the Working Group I part of the IPCC’s Sixth Assessment Report, Climate Change 2021: The Physical Science Basis released in August 2021. Chapter 3 is about using global climate models to answer the question of whether, to what extent, and by what mechanism humans are causing trends across many different aspects of the climate system, including in the atmosphere, ocean, land, and ice domains. 

NIWA Contacts