UKESM 1 Year Extension
Lead Research Organisation:
NATIONAL OCEANOGRAPHY CENTRE
Department Name: Science and Technology
Abstract
Global climate change is one of the leading environmental threats facing mankind. To develop appropriate mitigation and adaptation strategies requires accurate projections of the future state of the Earth's climate. To address this, we develop Global Climate Models (GCMs) that describe the main physical processes in the coupled climate system. These models are integrated forwards in simulated time, from a pre-industrial period to present-day, forced by observed estimates of key greenhouse gases, aerosols and land-use. The models are then continued into the future forced by a range of greenhouse gas, aerosol and land-use scenarios. Each of the model future climates can then compared to the simulated present-day climates. This analysis results in an ensemble of climate change estimates that can be used to assess the socio-economic and ecological impacts of the simulated changes and aid in the development of mitigation and adaptation policies.
GCMs have been further developed into Earth system models (ESMs), as we did in the UKESM LTSM, where UKESM1 was developed from the physical model, HadGEM3-GC3.1. A key difference between ESMs and GCMs is the former include an interactive description of the global carbon cycle supporting analysis of both physical climate change and potential changes in the efficacy by which anthropgenic emitted CO2 is taken up by natural carbon resevoirs. A reduction in the uptake efficiency of Earth's natural carbon reservoirs may result in a larger fraction of emitted carbon dioxide remaining in the atmosphere to warm the planet. Accurate estimates of the future evolution of both the global climate system and the carbon cycle are therefore crucial for getting a clear picture of the future risks humanity faces, as well as for developing mitigation actions (that typically target modifying the efficacy of carbon uptake) to keep global warming to acceptable levels.
To address this need we developed the 1st UK Earth system model (UKESM1) and ran it for a large suite of experiments in the 6th Coupled Model Intercomparison Project (CMIP6). UKESM1 is the most advanced Earth system model in the world today and as well as a coupled physical climate model also includes interactive treatment of (i) the global carbon cycle and vegetation, (ii) atmospheric chemistry and aerosols and (iii) models for the Greenland and Antarctic ice sheets. We have run a large (19 member) ensemble of historical simulations with UKESM1 (1850 to 2015) and extended a number of these into the future (2015 to 2100) following 7 different future emission pathways from CMIP6 scenarioMIP. In this extension we propose a deatiled analysis of the UKESM1 histroical ensemble and the suite of scenarioMIP projections. Our aims are (i) to better understand what drives observed historcal Earth system change and ask how well UKESM1 represents these changes, (ii) with the knowledge from (i), analyse simulated Earth systen change in the UKESM1 scenarioMIP ensemble, combining this with the CMIP6 multi-model ensemble, to document the range of simulated changes across the coupled Earth system over the coming century. Two primary emphases in this analysis will be; (a) to document and contrast regional changes at different levels of global mean warming (e.g. 2C or 3C) and (b) where possible, to constrain the various coupled feedbacks simulated by UKESM1 that drive the changes we see. In addition to these two science goals, we will also continue to provide support to the large UK UKESM user and model devleopment community and plan to hold two consultation workshops with (i) UK climate policymakers and (ii) UK climate impacts researchers. In thse workshops we will present our findings on predicted future Earth system change and begin a two-way dialogue on how UK Earth system modelling can best serve the needs of these two groups, developing future collaborations based on mutual understanding of each groups needs and goals.
GCMs have been further developed into Earth system models (ESMs), as we did in the UKESM LTSM, where UKESM1 was developed from the physical model, HadGEM3-GC3.1. A key difference between ESMs and GCMs is the former include an interactive description of the global carbon cycle supporting analysis of both physical climate change and potential changes in the efficacy by which anthropgenic emitted CO2 is taken up by natural carbon resevoirs. A reduction in the uptake efficiency of Earth's natural carbon reservoirs may result in a larger fraction of emitted carbon dioxide remaining in the atmosphere to warm the planet. Accurate estimates of the future evolution of both the global climate system and the carbon cycle are therefore crucial for getting a clear picture of the future risks humanity faces, as well as for developing mitigation actions (that typically target modifying the efficacy of carbon uptake) to keep global warming to acceptable levels.
To address this need we developed the 1st UK Earth system model (UKESM1) and ran it for a large suite of experiments in the 6th Coupled Model Intercomparison Project (CMIP6). UKESM1 is the most advanced Earth system model in the world today and as well as a coupled physical climate model also includes interactive treatment of (i) the global carbon cycle and vegetation, (ii) atmospheric chemistry and aerosols and (iii) models for the Greenland and Antarctic ice sheets. We have run a large (19 member) ensemble of historical simulations with UKESM1 (1850 to 2015) and extended a number of these into the future (2015 to 2100) following 7 different future emission pathways from CMIP6 scenarioMIP. In this extension we propose a deatiled analysis of the UKESM1 histroical ensemble and the suite of scenarioMIP projections. Our aims are (i) to better understand what drives observed historcal Earth system change and ask how well UKESM1 represents these changes, (ii) with the knowledge from (i), analyse simulated Earth systen change in the UKESM1 scenarioMIP ensemble, combining this with the CMIP6 multi-model ensemble, to document the range of simulated changes across the coupled Earth system over the coming century. Two primary emphases in this analysis will be; (a) to document and contrast regional changes at different levels of global mean warming (e.g. 2C or 3C) and (b) where possible, to constrain the various coupled feedbacks simulated by UKESM1 that drive the changes we see. In addition to these two science goals, we will also continue to provide support to the large UK UKESM user and model devleopment community and plan to hold two consultation workshops with (i) UK climate policymakers and (ii) UK climate impacts researchers. In thse workshops we will present our findings on predicted future Earth system change and begin a two-way dialogue on how UK Earth system modelling can best serve the needs of these two groups, developing future collaborations based on mutual understanding of each groups needs and goals.
Publications
Bock J
(2021)
Evaluation of ocean dimethylsulfide concentration and emission in CMIP6 models
in Biogeosciences
Brown P
(2021)
Circulation-driven variability of Atlantic anthropogenic carbon transports and uptake
in Nature Geoscience
De Mora L
(2023)
Scenario choice impacts carbon allocation projection at global warming levels
in Earth System Dynamics
Jacobs Z
(2021)
Key climate change stressors of marine ecosystems along the path of the East African coastal current
in Ocean & Coastal Management
Mulcahy J
(2023)
UKESM1.1: development and evaluation of an updated configuration of the UK Earth System Model
in Geoscientific Model Development
Planchat A
(2023)
The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle
in Biogeosciences
Vaittinada Ayar P
(2022)
Contrasting projections of the ENSO-driven CO 2 flux variability in the equatorial Pacific under high-warming scenario
in Earth System Dynamics
Woodward S
(2022)
The simulation of mineral dust in the United Kingdom Earth System Model UKESM1
in Atmospheric Chemistry and Physics
Description | The ocean plays a key role in modulating the climate of the Earth system (ES). At the present time it is also a major sink both for the carbon dioxide (CO2) released by human activities and for the excess heat driven by the resulting atmospheric greenhouse effect. Understanding the ocean's role in these processes is critical for model projections of future change and its potential impacts on human societies. A necessary first step in assessing the credibility of such future projections is an evaluation of their performance against the present state of the ocean. We used a range of observational fields to validate the physical and biogeochemical performance of the ocean component of UKESM1. Analysis focuses on the realism of the ocean's physical state and circulation, its key elemental cycles, and its marine productivity. UKESM1 generally performs well across a broad spectrum of properties, but it exhibits a number of notable biases. Physically, these include a global warm bias inherited from model spin-up, excess northern sea ice but insufficient southern sea ice and sluggish interior circulation. Biogeochemical biases found include shallow remineralization of sinking organic matter, excessive iron stress in regions such as the equatorial Pacific, and generally lower surface alkalinity that results in decreased surface and interior dissolved inorganic carbon (DIC) concentrations. The mechanisms driving these biases are explored to identify consequences for the behaviour of UKESM1 under future climate change scenarios and avenues for model improvement. Finally, across key biogeochemical properties, UKESM1 improves in performance relative to its CMIP5 precursor and performs well alongside its fellow members of the CMIP6 ensemble. |
Exploitation Route | Model output is publicly available |
Sectors | Environment |
URL | https://gmd.copernicus.org/articles/14/3437/2021/ |
Description | The WGI contribution to the Sixth Assessment Report published in August 2021 addresses the most up-to-date physical understanding of the climate system and climate change, bringing together the latest advances in climate science. At the core of this report is an ensemble of the global climate projections conducted within the framework of the Coupled Model Intercomparison Project (CMIP6), and delivered by the world-leading Earth system modelling groups. The UK contribution to CMIP6 is UKESM1, a collaborative development of UKMO and NERC centres. In this partnership, NOC played a leading role in developing and supporting the marine biogeochemical component of UKESM1, as well as to model spin-up and analysis (Yool et al., 2020; Yool et al. 2021). Through the parallel Joint Marine Modelling Programme (JMMP), NOC also develops and supports the physical ocean component underpinning UKESM1. UKESM1 projections are referenced in the IPCC AR6 WGI report more than 100 times, including in 29 Figures and 7 tables. 8 papers involving UKESM1 authors are cited in the report, with 5 involving NOC coauthors. |
First Year Of Impact | 2021 |
Sector | Energy,Environment,Government, Democracy and Justice |
Impact Types | Societal Economic Policy & public services |
Description | Contribution to teh IPCC WGI report |
Geographic Reach | Multiple continents/international |
Policy Influence Type | Citation in systematic reviews |
Impact | The WGI contribution to the Sixth Assessment Report published in August 2021 addresses the most up-to-date physical understanding of the climate system and climate change, bringing together the latest advances in climate science. The report aims at policymakers working in the area of global climate change mitigation and adaptation. At the core of this report is an ensemble of the global climate projections conducted within the framework of the Coupled Model Intercomparison Project (CMIP6), and delivered by the world-leading Earth system modelling groups. The UK contribution to CMIP6 is UKESM1, a collaborative development of UKMO and NERC centres. |
URL | https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Citation.pdf |
Description | Contribution to the IPCC report WG2 (Climate Change 2022: Impacts, Adaptation and Vulnerability. Working Group II Contribution to the IPCC Sixth Assessment Report) |
Geographic Reach | Multiple continents/international |
Policy Influence Type | Citation in systematic reviews |
Impact | Climate Change 2022: Impacts, Adaptation and Vulnerability The Working Group II contribution to the IPCC Sixth Assessment Report assesses the impacts of climate change, looking at ecosystems, biodiversity, and human communities at global and regional levels. It also reviews vulnerabilities and the capacities and limits of the natural world and human societies to adapt to climate change. Chapter 3: Oceans and Coastal Ecosystems and their Services: A.Yool served as a contributing author. The key MEDUSA publications were cited 11 times. MEDUSA's benthic submodel was used as a key evidence for the future of the benthic biomass. Figure 3.21j,k,l, from the WG2 report was re-drawn from Yool et al., 2017 |
URL | https://www.ipcc.ch/report/ar6/wg2/ |
Description | TerraFIRMA: Future Impacts Risks and Mitigation Actions |
Amount | £9,402,982 (GBP) |
Funding ID | NE/W004895/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 03/2022 |
End | 03/2027 |
Title | UK Earth System Model |
Description | UKESM1 (Sellar 2019) is a state-of-the-art Earth system model that consists of the following component models: The physical global climate model HadGEM3-GC3.1 (Williams 2018, Kuhlbrodt 2019), itself composed of the Unified Model atmosphere, NEMO ocean model and CICE sea ice model. Atmospheric Chemistry: UKCA interactive stratospheric-tropospheric chemistry model (Morgenstern 2009, O'Connor 2014, Archibald 2019). Atmospheric aerosols: UKCA-GLOMAP-mode stratosphere-tropospheric aerosol scheme (Mann 2014, Mulcahy 2020). Ocean biogeochemistry: MEDUSA2 intermediate complexity plankton ecosystem model Yool 2013). Terrestrial biogeochemistry: TRIFFID vegetation dynamics prognostic soil and vegetation carbon with nitrogen limitation (Clark 2011, Wiltshire 2020) Ice sheets: BISICLES land ice sheets for Antarctica & Greenland (Cornforth 2013, Smith 2020).Model components are coupled together using the OASIS3-MCT coupler (Craig 2017) |
Type Of Material | Computer model/algorithm |
Year Produced | 2019 |
Provided To Others? | Yes |
Impact | Scientific papers based on UKESM1 simulations form an important contribution to the Intergovernmental Panel on Climate Change (IPCC) - 6th Assessment Report (AR6). The IPCC provides policymakers with regular scientific assessments on climate change, its implications and potential future risks, as well putting forward adaptation and mitigation options. UKESM1 enables analysis of potential future changes in both the physical climate system (such as rainfall, temperature and storms) while also allowing analysis of changes in the Earth's biogeochemical systems, such as marine biology, forests and atmospheric gases, all within a single interacting model. UKESM1 historical and future projections have been analysed to understand the impacts on, for example, storm surges and coastal flooding, fisheries, agriculture and wind potential over discrete regions, such as the Arctic, the North Atlantic-Europe (with ACSIS) and the Southern Ocean/Antarctica (with ORCHESTRA), as well with respect to key regional phenomena, such as global monsoons and the El Nino-Southern Oscillation. |
URL | https://ukesm.ac.uk/portfolio-item/the-release-of-ukesm1-update/ |