The climate agreement signed in Paris on 12 December 2015 constitutes a significant milestone for protecting humanity from dangerous climate change. Climate scientists and economists, and many world’s leaders have been urging such large scale action for years. The extraordinarily efficient role played by Foreign Affairs Minister Laurent Fabius and other negotiators in Paris led to a commitment between 195 countries to maintain global warming below 2°C. Even though there was no clear plan to limit future CO2 emissions below 1,000 gigaton (emissions required to hold the 2° C target), the agreement initiated a new international dynamic that makes climate change a central theme for future economic, social, and cultural development and for environmental sustainability.
What then is our responsibility now that the agreements have been made? The scientific community has to provide objective scientific information that will facilitate climate smart solutions, and leads to sound priorities for the investment of the 100 billion dollars that have been committed in Paris. Actions towards deep decarbonization require a new way by which society conducts business, develops urban areas, manages land, produces energy, and organizes transportation. All these changes will require new transdisciplinary approaches and an intensified dialogue between different communities: scientists, engineers, industrialists, policy-makers, and other stakeholders. Climate services, which have been established in many countries of the world to provide authoritative climate information, should evolve towards development of innovative ideas and translate into climate-smart investments. In other words, climate services will have to increasingly provide usable information rather than just useful science.
Even though the emphasis today is on the implementation of effective solutions, the need for fundamental science remains vital, and will require high intellectual and financial investments. The World Climate Research Program (WCRP) has identified several relevant grand challenges that will address societally relevant questions. One involves the formulation of processes that determine how atmospheric circulation affects the climate sensitivity calculated in climate models. Another challenge is to acquire a better predictive understanding of extreme events that have large impacts on the economy and people’s lives. The prediction of regional sea-level change and its impact on coastal areas is another question that will be addressed because of its large impacts on populations that live near the ocean. Another challenge is to enhance our understanding of the processes that lead to massive melting of polar ice, and of the related impact on the global environment. A better understanding of the biogeochemical influence of the ocean and land on the carbon cycle remains an urgent question. Finally, many decision-makers in different sectors of the economy express high interest in seasonal-to-decadal climate predictions, which remains a difficult problem because it requires a better understanding of the complex internal dynamics of the climate system. All the fundamental issues should remain on the agenda of the scientific community in the coming years.
—Guy Brasseur, Editor, Earth’s Future; email: [email protected]