Since 1990 and the publication of the First Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), tens of thousands of scientists have come together to deliver the latest scientific evidence that the Earth’s climate is changing and that the majority of the observed change is due to human activity. Never before have so many scientists been willing to coordinate and dedicate their resources to address a global issue of such huge societal and economic relevance. The statistics are staggering. For the IPCC Fifth Assessment Report, the community generated 2 petabytes of climate simulation data, and over 850 scientists from 55 countries reviewed over 9 200 published papers on physical climate science. It was on the basis of this report that over 190 countries signed up, in Paris in 2015, to limit global warming to 2oC and, if possible, 1.5oC.
What is far less well known is that none of this would have been possible without the World Climate Research Programme (WCRP). The design, coordination and dissemination of the climate change scenarios that underpin the IPCC assessments was guided by the WCRP. Its activities have had a massive impact on climate change science, and has enabled a huge community of scientists to engage with the IPCC process.
The WCRP was established in 1980 under the joint sponsorship of WMO and the International Council for Science Unions (ICSU). In 1993, the Intergovernmental Oceanographic Commission (IOC) of UNESCO also became a sponsor. Since its inception, WCRP has focused on cutting-edge physical climate science. Its mission is to determine to what extent climate can be predicted, and the extent of man’s influence on climate.
WCRP does not fund research directly, but plays a unique role in facilitating and integrating climate research in areas where international coordination enables scientific advances that would not happen otherwise. It functions by engaging with, and gaining the commitment of, the international climate science community to its programme of work, and in turn ensuring that participants derive benefit from engaging in WCRP activities. Community engagement in WCRP is broad and strong, and the WCRP is recognized and valued for providing opportunities to work collaboratively to the greater benefit of the science. By bringing together international endeavours, WCRP provides massive gearing from national research funding. For example, the IPCC Sixth Assessment Report, due to be published in 2020, will draw on over US$4 billion worth of nationally-funded research.
The WCRP sponsors commissioned a major review of the programme as it approaches its 40th anniversary to ascertain its effectiveness in addressing 21st century demands for climate information on all time and spacial scales. Published in September 2018, this review makes a series of recommendations for how WCRP and its sponsors should plan its future and ensure that fundamental climate research continues to thrive and serve the needs of society.
More than ever, WCRP is needed
With the Paris Agreement, it might be tempting to conclude that climate research has provided the answers – the world is warming and that it is due to us – and that all is needed now are the technological advances to deal with the sources and effects of that warming. On the contrary, the review argues that core, underpinning climate science, which WCRP helps to deliver, is needed more than ever before. Society’s pressing need for solutions to the impacts of climate change (Paris Agreement), to mitigate disaster risk and improve resilience to disasters (Sendai Agreement), and to sustainable development for the planet (UN Sustainable Development Goals) heighten the importance of the climate research coordinated by WCRP.
Today, we live in a global economy, relying on international trade, efficient transport systems and resilient and reliable provision of food, energy and water. All these systems are vulnerable to adverse weather and climate. The additional pressure of climate change creates a new set of circumstances and poses new challenges. Over the coming century, exposure to the risks caused by a varying and changing climate will be compounded by rising population levels, increasing urbanization and the requirement to provide food, water and energy to the world’s people. We need to build more resilient nations, better prepared for weather and climate risks. We need to help governments and businesses make wise choices for future investment in adaptation. We need to guide the implementation of mitigation policies to avoid dangerous climate change. Without a strong foundation in climate science none of these challenges can be addressed in a robust, cost-effective and durable way.
Seamless weather-to-climate approach needed
Climate science has evolved substantially since WCRP was created. Advances in fundamental science, in observing the climate system and in complex simulations, combined with the exploitation of cutting-edge technologies, such as satellites and supercomputers, have revolutionized our understanding of the weather and climate we experience. These advances have enabled us to forecast future weather and climate behaviour with ever-increasing skill. Climate science now engages many different disciplines beyond meteorology –oceanography, chemistry, biology and many more. Climate models no longer consider just the physical climate system but increasingly include Earth system processes, such as the carbon cycle.
At the same time, the need for climate information on all space and time scales has led to the recognition that weather science is fundamental to climate science, that the same fundamental meteorology underpins them both. More seamless thinking across weather forecasting and climate prediction will be increasingly important. After all, we know that the biggest impacts of climate change will be felt through high impact weather, such as floods, storm surges and heatwaves. Much closer cooperation, therefore, is needed between the two communities, with greater alignment of their fundamental research, model development and prediction activities.
Traditionally, the WCRP has structured its activities around its four core projects each focusing on a fundamental element of the Earth System – atmosphere, land, ocean and ice (cryosphere). These served the community well, leading to some ground-breaking advances such as understanding the chemistry and dynamics of the ozone hole, the capability to observe, understand and predict El Nino, and assessing the contribution of glacier and ice-sheet melting to sea-level rise. However, the review concluded that the structure and remit of these projects may no longer be appropriate in an era in which more holistic Earth System and seamless weather-to-climate science approaches are needed. Today society requires science and services from the global to the local scale.
Core mission unchanged
The initial mission of the WCRP – to determine to what extent climate can be predicted, and the extent of man’s influence on climate – should remain the core pillars for the future WCRP. These pillars will need to take a holistic view of the climate system, bringing together the separate components of the climate system, and considering the synergistic relationship between weather, climate variability and climate change.
In answering the first question – to what extent can climate be predicted? – we now know that there are many drivers of climate variability on monthly to decadal timescales, beyond just the oceans, and including the sun and other components of the climate system. Finding predictable signals means that we need to include all these in our prediction systems and learn how each interacts with the whole system to reinforce or weaken predictability. The atmosphere and ocean are both dynamical fluids which can transmit signals from one part of the system to many other remote locations, around the globe. Known as teleconnections and modes of variability, unravelling the subtle climate dynamics associated with them remains challenging, but progress will be essential for understanding the changing volatility of our weather and climate as the planet warms.
The second core pillar addresses the extent of man’s influence on climate and asks some fundamental questions about climate sensitivity and how our understanding of it will evolve as we introduce new Earth System feedbacks, such as the carbon and nitrogen cycles, and melting permafrost. As the frequency of extreme weather and climate events seems to be growing year on year, there are inevitable questions about the influence of climate change. The provision of robust attribution for specific events is still in its infancy. The science is challenging, yet progress will be essential to guide investments in adaptation and building more resilient societies. And of course, WCRP must continue to play a pivotal role in IPCC by coordinating the design, delivery and assessment of climate scenarios. It will draw on the latest science and modelling capabilities to guide adaptation and mitigation policies and to underpin international agreements on emission reductions.
WCRP will need to ensure that it is underpinned by a third pillar on fundamental research on Earth system processes across timescales to achieve its core mission. For example, it should crosscut from the fast scales of organized cumulus convection to the slow scales of dynamic vegetation and melting ice-sheets. At the core of this activity is the recognition that understanding processes at fine scales, through observations, field experiments and simulation, is essential for developing parametrizations at the larger scale. It will ensure that climate and Earth system models are deliver reliable and robust simulations, predictions and scenarios. It is here that links with the weather science and forecasting community will be immensely valuable. They struggle with many of the same scientific and modelling problems, but have the advantage of being able to test models in a forecast environment.
These three enduring core pillars are designed to nurture long-term expertise and capabilities. At the same time, it will be essential that WCRP urgently address key scientific problems with explicit societal relevance, due to their specific impacts or as policy drivers, through international cooperation. To this end, WCRP will support a set of high-profile, but time-limited, crosscutting research projects. Potential examples include:
- Regional Sea Level Rise, Coastal Impacts and Cities
- Weather and Climate Extremes, now and in the future
- Water Cycle and the Food Baskets of the World
- Fate of the Antarctic and Greenland Icesheets.
These will enable WCRP to maintain a vibrant research portfolio, to engage with a broader cohort of scientists, and to enthuse and foster the next generation of science leaders.
Driving science forward
The review is very clear that the strength of WCRP must continue to lie in its focus on the fundamental, underpinning science. It is not its role to deliver end products and services. That would risk diluting its focus. It should, however, continue to maintain an active dialogue with the users and stakeholders of its science. This will deliver multiple benefits. WCRP will be able to articulate the value of its core science for addressing societal needs, and give users access to the latest scientific developments so that they can shape their services accordingly.
The scale of the enterprise that is now required may pose the greatest risk for the future WCRP, and for the climate science community in general. Modelling is a fundamental tool for delivering climate science, and yet model development continues to be hard work to prioritize and energize with research funders. Climate models have always been very compute-intensive. Over the decades, the availability of computing power has dictated the level of sophistication of the models and the type of simulations that can therefore be performed. There are few sciences where progress can be so closely linked to the increases in supercomputing power.
A major push is required in model development with the new agendas of seamlessness across weather, climate and Earth system science, of high resolution, fully coupled, Earth system modelling, and the advent of exascale computing. This implies building a new generation of codes. WCRP can play a vital role in supporting the community by driving the science for next generation Earth system modelling forward and by providing a forum for engaging with the vendors on the design of exascale machines to the benefit of all.
In summary, the review commended WCRP for its long and vital contribution to international climate research. However, together with its sponsors it must now plan its future in order to ensure that fundamental climate research continues to thrive and serve the needs of society as it tackles 21st century challenges. Acting as the recognized, international and collective voice for climate science, WCRP plays a critical advocacy role, interacting strategically with research funders and governments to ensure that society has access to the best possible scientific evidence. With the emergence of holistic Earth system modelling, of seamless weather and climate science, of the increasing skill and reliability of climate prediction, and growing requirement for an increasing range of climate projections from the global to the local to guide resilience, adaptation and mitigation actions, WCRP is needed more than ever before.