On 30 September 2021, CONSTRAIN hosted an online workshop on the role of climate model emulators in the Intergovernmental Panel on Climate Change 6th Assessment Report (IPCC AR6).
The workshop highlighted the use of climate model emulators – simple climate models designed to reproduce the behaviour of highly complex Earth System Models (ESMs) without the same demands on computing time and power – in AR6, focusing on the recently-published Working Group I (WGI) report on the physical science basis of climate change.
Many scientists, including from CONSTRAIN, worked to implement the use of climate emulators within WGI. Ultimately, this allowed multiple lines of evidence to be combined, and hundreds of climate projections to be produced, in ways that would have been impossible using more complex ESMs. Moreover, the emulators supported the IPCC’s and CONSTRAIN’s shared aim to produce open science, with accessible and readily available models and data. This approach also facilitated communication, collaborative working, and consistency across the AR6 process.
The workshop presentations focused on some of the many ways in which climate model emulators have contributed to AR6 to date, as well as their upcoming role in the AR6 Working Group III (WGIII) report on climate change mitigation, due in spring 2022.
These included their ability to investigate how global temperatures might change beyond 2100, and to assess future rates of change as well as when we might expect to cross 1.5°C and 2°C warming. The ability of emulators to investigate the role that methane, aerosols and ozone play in climate change, and to project sea level rise, was also highlighted.
The discussion which followed highlighted how emulators also present considerable opportunities to enhance climate research, for example by providing regional as well as global climate projections, as well as to investigate how climate extremes might evolve.
As well as their growing role in major climate science assessments, due to their relative simplicity and accessibility emulators can clearly be a useful tool for improving understanding of climate projections, among both scientists and interested stakeholders. The insights gained from the workshop will now be taken forward by CONSTRAIN and others to refine and promote their use of emulators in both climate science and broader decision-making.
Further information on climate emulators and their use in IPCC AR6 will be available in the CONSTRAIN project’s third ZERO IN Report on near-term warming and our chances of staying within 1.5°C, to be published shortly.