Climate Primer #3: The Second Planetary Boundary – Biodiversity Loss and Extinctions

To summarize the primers thus far, the build-up in Earth’s atmosphere of greenhouse gases emitted owing to human activity is causing the planet to heat up significantly. This is the clearest, and most dangerous, sign of the rapidly accelerating global climate crisis; however, while global heating and carbon dioxide may get disproportionate attention in the media, there are in fact a number of key planetary boundaries. Broaching any one of these would pose a threat to the stability of “organized human life on Earth” (a phrase I’m borrowing from Noam Chomsky), and so, in talking about climate crisis (which could use a more all-inclusive name), it’s necessary to consider not only the accumulation of greenhouse gases in the atmosphere and the consequent global heating, but the “manifold intersecting phenomena” that threaten to lead to the broaching of key boundaries within which we must remain to sustain (human) life on Earth.

Yesterday’s post addressed the risk of stratospheric ozone depletion – a threat which is, thankfully, owing to the 1987 Montreal Protocol, largely under control (though both the US and China continue to emit significant amounts of ozone-depleting substances). In continuing to draw on the schema established by the Stockholm Resilience Center, today’s post will focus on (mass) extinctions and biodiversity loss, or what the SRC also refers to as “Loss of biosphere integrity“:

The Millennium Ecosystem Assessment of 2005 concluded that changes to ecosystems due to human activities were more rapid in the past 50 years than at any time in human history, increasing the risks of abrupt and irreversible changes. The main drivers of change are the demand for food, water, and natural resources, causing severe biodiversity loss and leading to changes in ecosystem services. These drivers are either steady, showing no evidence of declining over time, or are increasing in intensity. The current high rates of ecosystem damage and extinction can be slowed by efforts to protect the integrity of living systems (the biosphere), enhancing habitat, and improving connectivity between ecosystems while maintaining the high agricultural productivity that humanity needs. Further research is underway to improve the availability of reliable data for use as the ‘control variables’ for this boundary.

In the SRC’s use of the marketizing term “ecosystem services,” you can see how fully the logic of neoliberalism has disfigured much of the research, thinking, and activism around climate and ecological issues, and yet, the fact remains: Human activity (specifically, the activities of the rich and the corporations and governments they control) is disrupting ecosystems; destroying habitats; and driving species into extinction at a geologically-significant scale. This impoverishes the Earth and human existence on it, in an immediate sense, but also threatens to undermine the agriculture and food systems on which human societies depend.

If the bonus material yesterday was encouraging, today, the news I’ll share is heavier: Some of you may already have read or heard that New York City’s weather in recent years has been subtropical, and – as I’ve been gradually catching up on pandemic-backlogged reading – I came across, this morning, this Nature Climate Change article entitled, “Evidence suggests potential transformation of the Pacific Arctic ecosystem is underway.” A fitting way to end today’s post, as – from equator to poles – the Earth is heating up, a reality to which all living things, ourselves included, will be forced to adjust. Unlike other living things, though, humans have a say in how this future unfolds.

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