Humans are an integral component of the Earth system as conceptualised by IGBP. João Morais recalls key milestones in IGBP’s engagement with the social sciences and offers some words of advice for Future Earth.
The iconic images of Earth beamed back by the earliest spacecraft helped to galvanise interest in our planet’s environment. The subsequent evolution and development of satellites for Earth observation has been intricately linked with that of IGBP and other global-change research programmes, write Jack Kaye and Cat Downy .
The Ocean in a High-CO2 World: Science highlights from the symposium
Eastern boundary upwelling systems, such as the California Current, are particularly sensitive to ocean acidification: the pH of their surface waters is already comparatively low and their change in pH for a given uptake of anthropogenic CO2 is particularly high. Eddy-resolving simulations  for the California Current System show that between pre-industrial times and present, the mean pH of the surface ocean has decreased by about 0.1 pH units. As a result, the aragonite saturation horizon has shoaled by ~100 m, bringing waters corrosive to calcifying organisms into the surface (euphotic) zone in a few eddies and in near-shore environments during upwelling (Figure 1). The model data agree with recent observations. Projections for 2050 (IPCC SRES A2-scenario) suggest an additional drop of pH by ~0.2 units and a widespread and year-round shoaling of the saturation horizon into the euphotic zone. Due to the high temporal and spatial variability that characterizes eastern boundary upwelling systems, organisms are exposed to a wide range of pH (variations of up to 0.3 to 0.4 units) and saturation states, making it difficult to define when critical thresholds are crossed. At the same time, these systems may today offer opportunities to study the response to organisms to low and varying pH and saturations states likely to be widely experienced in the future.
Figure 1: Model simulations of the shoaling of the aragonite saturation horizon (depth in m) in the California Current from 1750 to 2050 (snapshots for the month of August). White areas depict saturated (non-corrosive) waters to the sea floor.
Footnote 1. Produced with the ETH-UCLA Regional Oceanic Modeling System.
This final issue of the magazine takes stock of IGBP’s scientific and institutional accomplishments as well as its contributions to policy and capacity building. It features interviews of several past...
This issue features a special section on carbon. You can read about peak greenhouse-gas emissions in China, the mitigation of black carbon emissions and the effect of the 2010-2011 La Niña event on gl...