Greenhouse gas buildup, sardines, submarine eruptions and the possibility of abrupt degradation of intense marine upwelling ecosystems

Widespread hypoxia and massive eruptions of noxious, radiatively active gases currently characterize the world's strongest eastern ocean upwelling zone. Theory, modelling results and observations suggest that the world's coastal upwelling zones will undergo progressive intensification in response to greenhouse gas buildup. This presents the prospect of progressive development of similarly degraded marine ecosystems in additional regions and of a contributing feedback loop involving associated additions to the global buildup rate of greenhouse gases, resulting further increases in upwelling intensity, creation of additional sources of greenhouse gas emissions, and so on. Abundant sardine stocks might be a mitigating factor opposing the process.