Predictability of weather and climate

Abstract:

There is an urgent need for countries to transition their national food and land-use systems toward food and nutritional security, climate stability, and environmental integrity. How can countries satisfy their demands while jointly delivering the required transformative change to achieve global sustainability targets? Here, we present a collaborative approach developed with the FABLE—Food, Agriculture, Biodiversity, Land, and Energy—Consortium to reconcile both global and national elements for developing national food and land-use system pathways. This approach includes three key features: (1) global targets, (2) country-driven multi-objective pathways, and (3) multiple iterations of pathway refinement informed by both national and international impacts. This approach strengthens policy coherence and highlights where greater national and international ambition is needed to achieve global goals (e.g., the SDGs). We discuss how this could be used to support future climate and biodiversity negotiations and what further developments would be needed.

Abstract:

Since the 1980s, external forcings from increasing greenhouse gases and declining aerosols have had a large effect on European summer temperatures. These forcings may therefore provide an important source of forecast skill, even for timescales as short as a season ahead. However, the relative importance of external forcings for seasonal forecasts has thus far received little attention, particularly on a regional scale. In this study, we investigate forcing-induced skill by comparing the near-surface temperature skill of a multi-model ensemble of seasonal predictions from the Copernicus Climate Change Service archive to that of an uninitialised ensemble of Coupled Model Intercomparison Project phase 6 projections for European summers (June–July–August) spanning the years 1993–2016. As expected, predictive skill over southern Europe is larger for initialised seasonal predictions compared to uninitialised climate projections. However, for northern Europe, we find that predictive skill is generally small in current seasonal models and surprisingly even smaller compared to uninitialised climate projections. These results imply that further research is necessary to understand the role of external forcing on seasonal temperature variations over Europe.