High-level discussion of international climate science priorities

The World Climate Research Programme (WCRP) was established in 1980 after the first United Nations conference on climate to improve scientific knowledge of the climate, to use that knowledge to “quantify climate variability and predictability, and to identify and prevent possible human-induced climate changes that could affect the well-being of humankind”. WCRP now is sponsored by three parent organizations, notably the World Meteorological Organization (WMO), the International Science Council (ISC), and the Intergovernmental Oceanographic Commission (IOC) of UNESCO.

Over its lifetime, WCRP has made enormous contributions to advancing climate science. Notably, WCRP provided the scientific basis that led to the unequivocal agreement by the Intergovernmental Panel on Climate Change (IPCC) and eventually the Conference of Parties (COPs) that humans impact climate and that they have already led to a warming of the Earth’s climate by close to 1.5 °C (2010 – 2024 compared to 1850 – 1900), primarily through the release of climatically active atmospheric constituents – mostly fossil CO₂.

A significant improvement of the understanding of the coupled climate system goes back to WCRP’s internationally coordinated efforts in helping establish a comprehensive observing system and building increasingly complete and accurate climate modelling tools capable of delivering climate change projections over the 21^st century, considering various greenhouse gas emission scenarios.

Understanding climate processes and quantifying climate variability and changes required the establishment of various core research projects dealing with the atmosphere, the ocean, the cryosphere, and land surface processes, as well as their interactions. At the same time, seasonal, multi-year and regional prediction capabilities had to be developed in close collaboration with the weather and oceanographic communities. Largely through WCRP’s efforts, it is now possible to monitor, simulate and project global and regional climate and to provide climate information for use by governments for policy making, decision-making, and in support of a wide range of practical end-user applications.

Over the next decade, WCRP continues to develop new understanding of climate change processes and will develop an understanding of how they interact with society at global and regional scales. It will build upon the expertise of its longer-term scientific communities focussing on the energy, water and carbon cycles in the oceans, the cryosphere, the atmosphere, as well as on Earth system modelling and observations at global and regional scales.

Climate observations and numerical models will always be the fundamental tools for WCRP’s research. Information from both will be used in an integrated way using modern methods of data assimilation and analysis, attribution, historical and paleo-climate simulation, process studies, seasonal to interannual climate prediction, future climate projections, and regional downscaling. WCRP’s Coupled Model Intercomparison Project (CMIP) continues to provide the scenario runs assessed by the IPCC. The Coordinated Regional Downscaling Experiment (CORDEX) used by e.g., the climateinformation.org portal provides climate information and guidance for adaptation and mitigation activities.

In addition, WCRP has introduced six Lighthouse Activities, all intended to be bold and ambitious, large-scale time-limited projects, established to make rapid progress towards achieving urgent scientific goals. The current WCRP Light House activities are presented in Figure 1, including Digital Earths, which links to EU’s Destination Earth flagship initiative.

Figure 1. The WCRP Lighthouse Activities

Through these activities, WCRP will be better able to inform decisions on climate risk management and advance support of climate services; address the needs of the growing public and private sector (e.g., business, financial services sector etc.) demand for scientific advances in the understanding and predictability of global and regional climate change and variability and its impacts. Being a key international player in the development of science-based climate information analysis, synthesis and assessments that are needed to underpin vulnerability and adaptation strategies, the WCRP will support climate research determining processes responsible for the existence of regional climate hotspots. This line of research advances support of climate services, and mitigates the risk associated with extreme climate events.

Beyond existing activities, WCRP will fill gaps in our knowledge of the climate system, involving regionally relevant information down to the urban scale, compound extremes and event attribution, overshoot, tipping points, and air quality benefits of mitigation. Changing patterns of extreme weather (such as storms and heat waves) and climate-related events (such as droughts) can affect public health, national security, the economy, infrastructure, and other essential systems. Extreme events can interact and build on each other, creating multiple stressors that make it difficult to plan and improve preparedness. So called tipping points occur when Earth system changes become irreversible, leading to large-scale shifts in the Earth system that can have significant impacts on society. Identifying high-risk events and tipping points is critical to informing risk management strategies and is undertaken by e.g. WCRP’s Safe Landing Climates Lighthouse Activity.

Through the international coordination of a Global Precipitation Experiment (GPEX), WCRP will address major science gaps in the field of precipitation. Related activities will help accelerate advances in precipitation knowledge and prediction at different temporal and spatial scales, to enhance public access to relevant datasets, and to benefit society, by coordinating national and international activities. This will include African, Latin American and potentially European components of GPEX, of which the EU Commission and others could play a significant role. Eventually this will evolve into WCRPs decade of water which will deal with water in an end-to-end sense.

While adaptation is important to manage climate change impacts that we cannot avoid, only strong and rapid climate mitigation, reaching net zero emissions in the coming decades, can keep global warming below 1.5 degrees. It becomes increasingly unlikely that society can make this transition in time to avoid exceeding the Paris temperature goals. The question of whether climate intervention technologies should be considered as part of a mitigation strategy has been raised, noting the inherent risks this may involve for the future evolution of the climate system. The current state of understanding of Solar Radiation Modification is by far insufficient for supporting informed decisions. WCRP has set out on documenting current research gaps and to define new efforts in this respect, to be addressed with other international research programmes and partners. The subject of budgets and cycles of energy, water and carbon and their integrated interconnections, has been a major focus of discussions within WCRP. While research into energy and water coupling is strong and obvious over all timescales, carbon is also tightly coupled to the energy and water cycles across all time and space scales and therefore it is essential for WCRP to explore this cross-cutting theme. This coupling between energy, water and carbon also includes the fluxes between the oceans, atmosphere, and land. A limited duration task team has been set up within WCRP and is working on producing a strategy as to how research into coupled energy, water and carbon cycles, across all timescales and across land, atmosphere and ocean domains of the Earth system can be best coordinated and facilitated as a cross-cutting theme across the WCRP – in a way that is co-owned by all core projects and shares the interdisciplinary expertise that exists not only across WCRP but also with other partners such as the Global Climate Observing System (GCOS).