Planetary lines we shouldn’t cross

I filed this piece with Village magazine in October, charting the growing number of critical planetary boundaries that have now been breached, and why this matters.

ON ANCIENT mariners’ maps, areas of uncharted waters were often marked with illustrations of dragons and other mythological creatures to signal to the unwary that dangers lay ahead.

The modern equivalent of ‘Here be dragons’ is a project which began in the Stockholm Resilience Centre in 2009, with the aim of graphically mapping the nine key ‘planetary boundaries’ beyond which the dragons of ecological disaster lay in wait.

There have been two major updates on the original 2009 report, the latest of which was published this summer. The multidisciplinary team that carried out the research underpinning the report looked at climate change, biodiversity loss, chemical pollution, changes in the use of land and fresh water and the presence of the elements nitrogen and phosphorus.

Nothing was viewed in isolation; in dynamic Earth systems, every element interacts in complex and sometimes unexpected ways with every other element. “It’s pretty alarming: We’re living on a planet unlike anything any humans have seen before”, according to Jonathan Foley, director of Project Drawdown, who was involved in the original research.

Briefly, this year’s update established that six of these critical boundaries for the maintenance of a stable climate system and overall integrity of the biosphere have now been breached, with two others approaching the red zone.

Only one of the nine boundaries is currently considered to be in stable and satisfactory condition, and ironically, this is global ozone. Back in the 1970s and 1980s, damage to the stratospheric ozone layer was first of all established theoretically, then by observations, leading to a huge public reaction and strong and concerted intergovernmental action.

This was spearheaded by the US, culminating in the signing of the Montreal Protocol in 1987 and the rapid phasing out of CFCs, the seemingly inert man-made chemicals that were wreaking havoc in the upper atmosphere.

Make no mistake, we had a narrow escape. Had that action not been taken then, much of the southern hemisphere in particular would by now be bathed in deadly levels of ultraviolet radiation.

Among the most severely critical boundary breaches now occurring are as a result of the overuse of nitrogen and phosphorus, primarily as fertilizers. These chemicals are devastating many of the world’s waterways, leading to algal blooms and oxygen-free dead zones.

In Ireland, the toxic effects of nutrient overload into our waterways are becoming ever more apparent. Lough Neagh, the vast lake in Northern Ireland, is severely damaged as a result mainly of runoff from agriculture, as well as raw sewage and other contaminants.

Similar blooms are being reported across Irish lakes and estuaries, a situation that has notably worsened since the abolition of dairy quotas in 2015 and the subsequent rush to intensify industrial-scale dairying operations, using our political leverage at EU level to allow thousands of Irish farmers a derogation to exceed the EU’s scientifically established maximum safe limits for nitrates.

The overloading of the global atmosphere with powerful heat-trapping gases, mainly carbon dioxide and methane, means we have fundamentally altered the chemistry of the atmosphere of an entire planet, and this is playing out, as predicted, in ever more extreme weather events, from droughts, heatwaves and flooding events to more powerful storm systems.

The ferocious summer of 2023, which has seen devastating impacts across much of the northern hemisphere, is a harbinger of a far more dangerous future, with rising sea levels, coastal inundation and killer heatwaves and flooding disasters that force the permanent abandonment of entire regions.

While life is about to become much more precarious and difficult for many millions of people, human impacts have already laid waste to much of the natural world, pushing tens of thousands of species into extinction and drastically reducing both the numbers and range of millions more.

This is the planetary boundary known as ‘biosphere integrity’ and the world’s genetic diversity has been severely depleted as a result of human actions. The current extinction rate is thousands of times higher than the natural or ‘background’ extinction rate. A key driver of extinction has been the destruction of ecosystems and their sequestration for agriculture, fishing, mining, fossil fuel extraction and commercial forestry.

Another boundary that has been smashed is termed ‘novel entities’. This innocuous phrase describes the witches’ brew of tens of thousands of toxic artificial chemicals, from plastics and pesticides to PFAs, the so-called “forever chemicals” that have been casually unleashed into the biosphere.

Even in the relatively well regulated European Union, around 80% of man-made chemicals are brought into use with little or no testing or true understanding of their long-term impacts.

To paraphrase Oscar Wilde, breaching one critical planetary boundary is unfortunate; to breach six is beginning to look like carelessness.

ThinkOrSwim is a blog by journalist John Gibbons focusing on the inter-related crises involving climate change, sustainability, resource depletion, energy and biodiversity loss
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