The Intergovernmental Panel on Climate Change’s (IPCC) Sixth Assessment Report, Climate Change 2021 – The Physical Science Basis, was published on Monday 9 August 2021.
The Intergovernmental Panel on Climate Change is the United Nations body for assessing the science related to climate change.
Many hundreds of scientists from around the world contributed to this report, which provides an assessment and synthesis of peer-reviewed literature on climate science.
Five CSIRO scientists were part of Australia’s 14-person author group.
It includes information on the rates, causes and likely future trajectories of global warming and other changes in the climate system.
What are the findings of the report?
The report provides information about climate change across the globe. It contains more regional information than any previous IPCC assessment.
The report’s summary document (known as the Summary for Policymakers) distils the global findings into 14 high level statements across four topic areas:
- The current state of the climate
- Our possible climate futures
- Climate information for risk assessment and regional adaptation
- Limiting climate change.
Global findings that are relevant to Australia include:
- Large-scale indicators of climate change in the atmosphere, ocean, and cryosphere are reaching levels, and changing at rates, unseen in centuries to many thousands of years.
- It is virtually certain that the frequency and intensity of hot extremes and the intensity and duration of heatwaves have increased across most land regions since 1950.
- Marine heatwaves have become more frequent in the 20th century, human influence has very likely contributed to 84–90 per cent of them since at least 2006.
- The frequency and intensity of heavy precipitation events have increased over most land regions with good observational coverage, and human influence is likely the main driver of the increases.
- Human influence has contributed to drought in particular during the dry season over most land areas due to increase in atmospheric evaporative demand.
Regional factsheets have been produced by the IPCC, including a factsheet on the Australasian region.
The IPCC’s findings relevant to the Australian region are consistent with the State of the Climate 2020 report published by CSIRO and the Bureau of Meteorology.
How did CSIRO contribute to the IPCC report?
Five CSIRO scientists were involved in the authorship and editing of the report.
They contributed to areas including global carbon cycles, oceans and sea level change, climate change projections and regional impacts of climate change.
Specifically, this is related to the Atlas of Global and Regional Climate Projections and chapters 5, 9 and 12.
Peer-reviewed science by CSIRO scientists has also been considered as part of the report.
CSIRO scientists are contributing to other parts of the IPCC’s Sixth Assessment Report, including the volume on Impacts, Adaptation and Vulnerability, which is currently scheduled for publication in February 2022.
CSIRO scientists work closely with research and academic partners to deliver climate, ocean and atmospheric research to a broad community of end users across many sectors of Australian industry and government. Find out more about CSIRO’s climate change research.
Where can I access Climate Change 2021: The Physical Science Basis?
The full report, Summary for Policymakers document, regional factsheets and other resources can be accessed at https://www.ipcc.ch/assessment-report/ar6/