This article is divided into three parts. Part 1 is the scene-setter, a rundown of humanity’s overshoot predicament and how we got into it. Part 2 chronicles my career-long response to understanding overshoot from an ecological perspective. If you’re still with me for Part 3, I share a few lessons learned and offer some advice for coping with the challenges of both knowing about and experiencing the consequences of overshoot.
Part 1. Some History of Humanity’s Overshoot Predicament
Over a decade ago, one of the most comprehensive assessments of global climate to date showed that the mean global temperature for the first decade of this century was approaching the highest levels in the past 11,000 years. A more recent article suggests that temperatures in the early 2020s are actually unprecedented in the past 24,000 years, and that the magnitude and rate of heating over the last 150 years far exceeds the magnitude and rates Earth has experienced over the entire 24-millennia period. It is no surprise, then, that the US National Oceanic and Atmospheric Administration (NOAA) recently declared 2023 to be the warmest year in the instrumental record and that Antarctic sea ice coverage had dropped to a record low.
The beat goes on—the most recent data available show January, February and March 2024 to be the hottest January, February and March on record (just the latest in a series of ten). Looking ahead, our current policy track would result in ~2.7 Co mean global warming by century’s end, and one credible study argues that, with fast and slow feedbacks, even current atmospheric greenhouse gas concentrations are sufficient to generate 10 Co heating. But even 2.7 degrees warming is sufficient to flatten agriculture in many areas and render large areas of Earth uninhabitable. Analysis shows under a range of warming scenarios, that the projected geographical shift in the normal human temperature niche by 2100 would force the unprecedented migration of one to three billion people to thermally safer parts of the planet. Picture the abandonment of major cities and megacities, the invasion of rural areas by desperate millions and an ungovernable world in geopolitical turmoil.
And that’s just global heating. Alarming as these data are, global heating is only the most palpable symptom of climate change which is, itself, only one co-symptom of a much greater meta-problem, ecological overshoot. Overshoot means that:
Humans are consuming even self-producing resources (e.g., fish stocks, forests) and replenishable resources (e.g., fresh-water aquifers, arable soils) faster than they can regenerate and producing (often toxic) waste in excess of nature’s assimilation capacity.
Think about that for a moment. You should soon realize that virtually all so-called “environmental” problems are actually caused by overshoot. Even anthropogenic climate change is an excess waste problem. (Carbon dioxide is the greatest waste product by weight of industrial activity.) The numerous other co-symptoms of overshoot include plunging biodiversity, fisheries collapses, tropical deforestation, land/soil degradation, groundwater depletion, rising cancer rates, falling sperm counts, contaminated food chains, the pollution of everything, etc., etc., most of which are worsening with each new assessment.
It should be clear from this dismal accounting that, left unattended, overshoot is a terminal condition. The depletion and pollution of the ecosphere is a genuine existential threat, not only to human “civilization” but also to the existence of thousands of other species with whom we share the planet. It is therefore a supreme irony that everything the world community is doing to address global heating—switching to wind and solar electricity, promoting dubious CO2 extraction technologies, subsidizing electric vehicles, etc.—is not only not fixing the climate but is actually worsening overshoot. Fossil fuel use is still increasing, and carbon dioxide and other greenhouse gas (GHG) emissions rise to new records annually. Yet we remain in effective policy paralysis.
How stupid is that?