To summarize, climate crisis is the defining issue of the century. Buildup of anthropogenic greenhouse gases (GHGs) in Earth’s atmosphere is driving global heating, while a convergence of global crises threatens to rupture key planetary boundaries. Although the human activities which drive these converging crises (for simplicity: the climate crisis) are diverse and complex, the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) breaks down the sources of anthropogenic GHG emissions into five high-level sectors. Similarly, the impacts of climate crisis – in their variety and complexity – are almost impossible for an individual to grasp, but so far, this sub-series has covered: global heating, Arctic amplification, heat waves, droughts and floods, disruption of oceanic and atmospheric patterns, cryosphere collapse, declining oceanic dissolved oxygen content, and sea level rise. In the absence of dramatic global climate action this decade, climate crisis will likely spiral out of control, rupturing key planetary boundaries and endangering the future of organized human life on Earth.
Today’s post centers the threat to global fisheries, which are a key source of food for something like 20% of the world’s population (depending on the parameters). Although in the near- to medium-term, climate change can have mixed effects on marine fisheries – actually increasing fish populations in some places owing to warming – the net impact of heating and acidification of oceans, the proliferation of anoxic zones (that is, large ocean dead zones with very low oxygen content, which often form owing to eutrophication caused by runoff of agricultural fertilizers), and overfishing – plus progressive habitat loss for many species as climate crisis deepens/accelerates – is very likely to be a significant decline in marine fish populations, even as the human population on Earth continues to grow.
Lest I seem guilty of the old Population Bomb conceit (that is, blaming the masses of the global poor, as a way of eliding the overconsumption of the global rich), it’s worth noting that animal protein, in general, is disproportionately consumed by people in rich countries and rich people in those countries which are middle income or poor. My own position on this is a touch hypocritical, as I still eat fish and shellfish, plus occasionally cheese and eggs, when I eat out; however, at home, we’ve been effectively vegan for some time, and in the spirit of harm reduction (which, at this point, is definitely not enough), I’ll call our own shifts in habits progress. If you’re looking for a small, readable book on veganism that’s not too preachy and that does make the connection to climate crisis quite effectively (though, I’d argue, is a bit confused politically on some other fronts, including with relationship to US colonialism and imperialism), you might consider picking up Jonathan Safron Foer’s We Are the Weather: Saving the Planet Begins at Breakfast.
As for collapsing fisheries, here’s a little of what AR5 has to say:
Climate / Change 
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