The Intergovernmental Panel on Climate Change (IPCC) is a body established in 1988 under the framework of the United Nations to assess climate change science. The IPCC’s primary objective is to provide governments around the world with correct and current scientific information related to climate change that can be utilized to develop climate change policies. This scientific information is generally presented by the IPCC through a series of reports. Every 5-7 years the IPCC begins a new assessment cycle, during which 4 reports are created and published about different aspects of climate change. Since 1990, the IPCC has completed 5 assessment cycles and is currently in the 6^th cycle. The IPCC’s next series of reports will be published in late 2022.

The fifth assessment cycle, published in 2014, brought to light new information and growing concerns related to climate change that had not been previously expressed. For example, the IPCC confirmed that more than half of the increase in global warming, ocean warming, disappearance of ice, and impacts to the global water cycle actually results from anthropogenic forcings, which is a greater percentage than the fourth assessment cycle had found. The 2014 report also highlighted new issues that had not previously been emphasized, such as the impacts on biodiversity, the increase in extreme weather events, and socioeconomic impacts on disadvantaged communities. Furthermore, the 2014 reports place a heavier emphasis on the need for immediate mitigation. Without immediate mitigation, there is a risk that the impacts of climate change will not be able to be slowed. Overall, the overarching risks of accelerated climate change outweighs the possible negative impacts countries face from implementing mitigation options. The anticipated 2022 report will likely emphasize this point even further.

The Reports

The 4 reports published in each assessment cycle include the following: the Synthesis report; the Mitigation of Climate Change report; the Impacts, Adaptation, and Vulnerability report; and, the Physical Science Basis report. In addition to the reports created during assessment cycles, special reports are also created in-between the assessment cycles on other climate change topics.

The IPCC does not conduct its own research for the reports which it publishes. The Panel works with scientists and policy-makers to identify areas of agreement and areas where there are gaps in the scientific knowledge of climate change. The IPCC collaborates with experts who are organized into three working groups and a task force to create the assessment cycle reports and special reports.

A brief description of the contents of each assessment cycle report is provided below.

The Physical Science Basis

This report is written by Working Group I. The report provides a full scientific and technical assessment of a variety of topics related to climate change on both global and regional scales, such as greenhouse gases, changing temperatures and weather, glaciers and ice sheets, and sea level change. In addition, this report provides important information directly related to policy creation. For example, the working group provides an assessment of the amount of carbon emissions that would allow countries to reach their climate targets, as well as the interactions between land, air, and the climate.

Impacts, Adaptation and Vulnerability

This report is written by Working Group II. It assesses the impacts of climate change on natural and human systems, including their limits and potential to adapt to a changing climate.

Mitigation of Climate Change

This report is written by Working Group III. It provides an assessment of the available options for mitigating climate change through preventing further emissions of greenhouse gases. This report also identifies methods that can be used to reduce the current atmospheric concentrations of greenhouse gases. Options for mitigation are technological, economic, or institutional in nature. For each option, a cost-benefit analysis is provided, as well as the potential risks and opportunities highlighted. Therefore, the Mitigation of Climate Change report effectively provides decision-makers with different pathways that may be taken to reach climate policy goals.

Synthesis Report

This report is written based on the three working group reports above, as well as any existing special reports. It is the final report released in an assessment cycle and is meant to provide decision-makers with an overview of the current state of knowledge on climate change science and what changes have occurred since the previous assessment cycle. It consists of a short, 10-page summary for policy and decision-makers, as well as a longer 50-page report that is more comprehensive.

Task Force on National Greenhouse Gas Inventories

The Task Force on National Greenhouse Gas Inventories acts separately from the working groups. It has worked in the development of globally accepted methods and software for calculating and reporting greenhouse gas emissions and has published reports through the IPCC to encourage the widespread adoption of their methods and software.