05 Climate models Ladislava Řezníčková, MSc, PhD Content 1. Climate models 2. Emission scenarios 3. Climate change scenarios What is a climate model? • quantitative mathematical description of aspects of the Earth’s climate system based on physical, chemical and biological properties of its components, its interactions and feedback processes • increase our understanding of how the climate system works • simulate past climate fluctuations to help interpret historical and paleo observations • simulate the future climate based on scenarios for emissions of GHGs Purpose of a climate model Climate projections - to better inform decisions of national, regional, and local importance (water resource management, agriculture, transportation, and urban planning) Climate models Climate models The climate system components https://www.energy.gov/science/doe-explainsearth-system-and-climate-models Climate models https://www.gfdl.noaa.gov/climate-modeling/ Weather vs climate models https://blogs.reading.ac.uk/weather-and-climate-at-reading/2022/weather-vs-climate-prediction/ https://www.youtube.com/watch?v=Pn3ZKB1XLiQ Development of climate models https://bookdown.org/floriandierickx/bookdown-demo/climate-data-from-models.html Complexity of climate models https://bookdown.org/floriandierickx/bookdown-demo/climate-data-from-models.html Spatial and Temporal Resolution https://bookdown.org/floriandierickx/bookdown-demo/climate-data-from-models.html Types of climate models 1.Global Climate/Circulation Model (GCM), Earth System Model (ESM) - simulate the climate of the whole world 2.Regional Climate Model (RCM) - simulate the climate only for a part of the world 1.Atmospheric models 2.Coupled models (ocean and atmosphere) 3.Earth System models (couple even more systems) 4.Specific climate models Models with more or less complexity/coupling: EBM – Energy Balance Model http://www.climate.be/textbook/chapter3_node6.xml • analysis of the energy budget of the Earth • basic processes and feedbacks • a large degree of parameterization • zero-dimensional EBMs Parametrization - some processes are not explicitly included in models because of simplifications, lack of knowledge of the mechanisms, or because the spatial resolution of the model is not high enough to include them. They are represented by parameterisations in models. EMIC - Earth Model of Intermediate Complexity http://www.climate.be/textbook/chapter3_node7.html • including the geography of the Earth • grid size 300–1000 km GCM – General Circulation Model grid size 100-200 km more detailed information on a regional scale Multi-model ensemble Earth system model • CMIP6: The Coupled Model Intercomparison Project https://mpimet.mpg.de/en/science/projects/integrated-activities/translate-to-englisch- cmip6-das-gekoppelte-modellvergleichsprojekt Global (GCMs) vs Regional climate models (RCMs) RCMs • use global model outputs as boundary conditions to calculate conditions in limited (smaller) areas with higher spatial resolution • significantly lower reliability. • Climate models are used together with emission scenarios to calculate the probable future climate, so-called climate scenarios/projections. • The climate models describe how the earth's climate functions, while the emission scenarios describe the impact of humans on the environment. • If the climate models are combined with the emission scenarios, it is possible to predict with a certain amount of probability how the climate will be in the future. What are emission scenarios, climate models and climate scenarios/projections? Climate scenarios • possible future of the Earth´s climate • based on its current observed state and different GHG emission scenarios • potential impacts of anthropogenic climate change • climate projections • not a forecast of the future climate • alternative possibilities of how the future can develop MODEL DESCRIPTION OF THE CLIMATE SYSTEM MODEL DESCRIPTION OF WORLD DEVELOPMENT CLIMATE SCENARIO components processess chemistry feedbacks economic activity new technologies population upper estimatelower estimate best estimate • the United Nations body for assessing the science related to climate change, • provides regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation, • currently has 195 members. The Intergovernmental Panel on Climate Change (IPCC) The Intergovernmental Panel on Climate Change (IPCC) The Intergovernmental Panel on Climate Change (IPCC) • First Assessment Report (FAR, 1990), Supplementary Report (1992) • Second Assessment Report (SAR, 1996) • Third Assessment Report (TAR, 2001) • Fourth Assessment Report (AR4, 2007) • Fifth Assessment Report (AR5, 2013-2014) • Sixth Assessment Report (AR6, 2021-2023) Assessment Reports 2021–2023: Sixth Assessment Report (AR6) The Intergovernmental Panel on Climate Change (IPCC) Emissions Scenarios • possible future development of GHG concentrations based on the fulfilment of certain assumptions • First scenarios: IPCC FAR 1990, new for each AR • They include the main demographic, ecological and technological influences on future emissions of GHGs, sulfur compounds, aerosols, etc. • used in: IPCC TAR (2001) IPCC AR4 (2007) • do not take into account any current or future measures to limit GHG emissions Special Report on Emissions Scenarios (SRES), 2000 https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-spm-1.pdf Projected global average surface warming and sea level rise at the and of the 21st century RCP - Representative Concentration Pathways (2011) https://tntcat.iiasa.ac.at/RcpDb/dsd?Action=htmlpage&page=welcome • different climate change scenarios, all of which are considered possible depending on the amount of GHGs emitted in the years to come SSP - Shared Socioeconomic Pathways (2021) https://en.wikipedia.org/wiki/Shared_Socioeconomic_Pathways Predicted atmospheric CO₂ concentrations for different SSPs across the 21st century Assessed projected change in 20-year running mean global surface temperature for five scenarios Climate projections until the end of the 21st century (IPCC, AR6) Climate projections until the end of the 21st century (IPCC, AR6) Changes in global surface temperature for selected 20-year time periods Global surface temperature estimate for SSP1-2.6 and SSP5- 8.5. in 2081–2100 relative to 1995–2014 Climate projections until the end of the 21st century (IPCC, AR6) Climate projections until the end of the 21st century (IPCC, AR6) Seasonal mean precipitation change from SSP1-2.6 and SSP3-7.0 in 2081– 2100 relative to 1995–2014 Climate projections until the end of the 21st century (IPCC, AR6) Scenarios, global warming levels, and patterns of change https://www.youtube.com/watch?v=YIFCSZYU2LM AR6 Synthesis Report: Climate Change 2023 https://www.ipcc.ch/report/ar6/syr/downloads/report/IPCC_AR6_SYR_SPM.pdf The Synthesis Report is based on the content of the three Working Groups Assessment Reports: WGI – The Physical Science Basis, WGII – Impacts, Adaptation and Vulnerability, WGIII – Mitigation of Climate Change, and the three Special Reports: Global Warming of 1.5°C, Climate Change and Land, The Ocean and Cryosphere in a Changing Climate. Thank you for your attention LD