Authors' Summary: The differences in phytoplankton variability through time observed at fixed locations (Eulerian perspective) or following water parcels (Lagrangian perspective) are poorly understood. We created a large set of satellite chlorophyll matched time series pairs in the Eulerian and Lagrangian perspective, using global drifter trajectories as an approximation of how surface ocean currents move.

We found that for most ocean locations, chlorophyll variability measured in Eulerian and Lagrangian perspectives is not different. In high latitude zones, chlorophyll appears to vary similarly over large areas. However, in localized regions of the ocean, such as western boundary currents and upwelling regions, chlorophyll variability in these two perspectives may significantly differ. The causes are linked to the specific ocean dynamics of each area.

Authors' Summary: This Compendium Volume presents a series of guidance notes and more detailed complementary technical notes that offer practical insights in support of enhancing the climate resilience of infrastructure investment projects in Sub-Saharan Africa. This first introductory chapter starts with an overview of the investment conditions and climatic context in the region, followed by a description of the scope of this Compendium Volume and individual notes, target audiences, and a roadmap for users of the contents covered in this Volume.

Abstract: We present results from large ensembles of projected 21st century changes in seasonal precipitation and near-surface air temperature over Africa and selected sub-continental regions. These ensembles are a result of combining Monte Carlo projections from a human-Earth system model of intermediate complexity with pattern-scaled responses from climate models of the Coupled Model Intercomparison Project Phase 6. These future ensemble scenarios consider a range of global actions to abate emissions through the 21^st century. We evaluate distributions of surface-air temperature and precipitation change. In all regions, we find that without any emissions or climate targets in place, there is a greater than 50% likelihood that mid-century temperatures will increase threefold over the current climate’s two-standard deviation range of variability. However, scenarios that consider more aggressive climate targets all but eliminate the risk of these salient temperature increases. A preponderance of risk toward decreased precipitation exists for much of the southern Africa region considered, and this is also compounded by enhanced warming (relative to the global trajectory). Over eastern and western Africa, the preponderance of risk in increased precipitation change is seen. Strong climate targets abate evolving regional hydroclimatic risks. Under a target to limit global climate warming to 1.5˚C by 2100, the risk of precipitation changes within Africa toward the end of this century (2065-2074) is commensurate to the risk during the 2030s without any global climate target. Thus, these regional hydroclimate risks over much Africa could be delayed by 30 years, and in doing so, provide invaluable lead-time for national efforts to prepare, fortify, and/or adapt.