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, sea level rise, fisheries collapse, and coral reef die-offs. 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.
Previous posts have already hinted at the threat to Earth’s forests posed by climate crisis, but it’s important to note – as the following excerpt from AR5 does – that climate crisis will bring an “increased risk of fires, pest and disease outbreaks,” in addition to the threat of habitat loss from changing climate (that is, many regions of the planet getting hotter and/or drier) and the damage done by logging, development, and other ecologically unsound human land-use practices:
I’ve written elsewhere about the catastrophic 2019 fires in Australia, the Amazon, and California. Less attention is paid to the Boreal forests that ring Earth’s northern latitudes, but in 2019, ~25x as much area burned in Siberia as burned in California. (For context, although the oceans hold the vast majority of the carbon stored in our planet’s biosphere (~15x the amount stored in the terrestrial biosphere, which in turn exceeds that which is held in Earth’s atmosphere), of the terrestrial carbon, just shy of 50% of it is contained in Earth’s forests.) And, of course, for anyone with feelings, forests are much more than carbon sinks.