Over the Earth’s 4.5-billion-year history, five catastrophic extinctions have changed its biological foundation.
The Ordovician-Silurian Extinction, 443 million years ago, was likely caused by severe ice ages, whereas the Devonian Extinction, 359 million years ago, was caused by changing ocean oxygen levels.
The worst, the Permian-Triassic Extinction, killed most life 252 million years ago owing to volcanic activity and climatic change. The Triassic-Jurassic Extinction, 201 million years ago, was caused by volcanic activity, while the Cretaceous-Paleogene Extinction, 66 million years ago, was caused by an asteroid.
Each mass extinction is linked to situations where the Earth’s biocapacity was stretched to its “planetary boundaries,” either by catastrophic natural events or significant environmental changes, causing ecosystem collapse and the extinction of many species.
It’s a stark reminder that the stability of Earth’s environments and ecosystems, even in the face of cosmic or
geological adversity, is pivotal for the persistence of life.
Developed in 2009 by leading environmental scientists, the planetary boundaries framework outlines a safe operating space where humanity can continue developing sustainably. It is fundamentally premised on the stable
climatic and ecological conditions of the Holocene epoch.
The framework identifies nine critical planetary life support systems and specifies quantitative boundaries intended to prevent harmful, and possibly catastrophic, shifts in Earth’s environment by averting the crossing of thresholds that risk triggering abrupt, non-linear environmental alterations on a continental to planetary scale.
The nine boundaries encompass climate change, ocean acidification, stratospheric ozone depletion, biogeo-
chemical flows (pertaining to nitrogen and phosphorus cycles), global freshwater use, land system change, biosphere integrity, chemical pollution, and atmospheric aerosol loading.
With a better knowledge of planetary boundaries, including them in the climate debate becomes critical. However, in the contemporary discourse on environmental shifts, climate change is prominently featured, with a sharp focus on rising greenhouse gas emissions and fossil fuel exploitation.
As a result, billions of dollars of pledges are made to address these concerns from governments and organisations worldwide. However, underneath these allegedly constructive steps sits a persistent flaw: a superficial understanding of the situation at hand.
As a result, although beneficial, our collaborative efforts may be misdirected, which is evident in the current trajectory of 3.4 degrees that we are perched on. Our path to overcoming this epochal challenge must go beyond simply mitigating and adapting to its visible impacts and into a deeper examination and rectification of its root causes, providing us with more than a superficial band-aid solution.
Two key metrics must be studied to determine the root cause of the current environmental disaster: “Humanity’s ecological footprint” and “Earth’s biocapacity.” What we take from the Earth, the pollution we produce, and the harm we inflict on ecosystems are all aspects of our ecological footprint, which illustrates the extent of our effect on the planet.
Earth’s biocapacity, on the other hand, displays our planet’s capacity to absorb this effect via resource regeneration, pollution absorption, and ecosystem recovery.
When our ecological footprint surpasses the Earth’s biocapacity, we overshoot our planetary boundaries.
Simply put, we’re extracting more than the Earth can sustainably provide, emitting more than it can absorb, and damaging ecosystems faster than they can recover.
Since the Paris Accords of 2015, six crucial planetary boundaries have been breached, highlighting the fragility of our biophysical systems and signaling a pressing need for adaptive governance and management strategies across various scales.
Specifically, climate change has seen a CO2 concentration surge from a planetary boundary value of 350 ppm to a
current value of 417 ppm; biosphere integrity has been altered from a preindustrial species extinction rate of 0.1-1 per million species per year to a staggering current rate of 100-1000; land-system change has escalated from a low pre-industrial value to a present value of 62% of terrestrial ecosystems now being impacted by humans; and
the altered biogeochemical cycles have shifted from a pre-industrial value of -1 Mt/year and 0 Mt/year for phosphorous and nitrogen to approximately 22 Mt/year and 190 Mt/year.
This data highlights that this is not merely a climate anomaly but a multifaceted, systemic, and global crisis of sustainability, suggesting that we have now left the Holocene and are transitioning to the Anthropocene, a
geological epoch aptly named to reflect human impact on the planet.
Another issue is how sustainability is often assessed through an ecological lens when population growth, poverty, inequalities, financial instability, geopolitical tensions, and societal polarisation directly impact sustainable transition as well.
Navigating the sustainability crisis demands a deep dive into its root causes, prominently stemming from human behaviour patterns linked to a materialistic and consumer-driven global economy.
The ensuing overexploitation of Earth’s resources and ecosystems emanates from an economy fostering unfettered competition, capital accumulation, and growth. This has unveiled a global-scale tragedy of the commons, perpetuated by negligence and greed.
In Pakistan, the persistent narrative that underscores its less than 1% contribution to global emissions obfuscates the pressing local environmental realities that demand immediate rectification.
Warming can be divided into three levels: local, regional, and global. While Pakistan’s global emissions are negligible, the annual smog enveloping Lahore emanates not from the global north, but from unsustainable
practices rooted firmly in local soil.
The impact of local ecological decisions is nothing short of devastating, with 128,000 estimated annual deaths from air pollution and a potential seven-year dip in life expectancy, as highlighted by the University of Chicago’s Air Quality Life Index report.
The Sahiwal coal plant, an epitome of “criminal neglect,” according to ex-climate adviser Malik Amin Aslam, is not only jeopardising public health, manifested in respiratory and skin diseases, but is also intensifying environmental plights, such as plummeting groundwater levels by 15 feet within a few years.
In the face of a looming global sustainability crisis, our collective denial and apathy have pushed us perilously close to the precipice of the sixth mass extinction. Our path, paved by apathy and avoidance, accelerates towards an ecological disaster unless we pivot towards acknowledgment and action.
While the situation demands a robust emotional and mental response, it also unveils a unique opportunity to enact meaningful change and reinvent our societal systems.
At least three considerations indicate that climate change must be addressed ethically.
First, we must recognise that we are part of creation and are entrusted with its care. We are not given free rein to abuse creation but rather are held accountable for its upkeep.
Second, we cannot abuse nature and leave our mess for future generations to clean up: intergenerational equity requires that we act in the present.
Finally, we must care for people who are disproportionately impacted by climate change and lack the means to adapt.
THE WRITER IS A SUSTAINABILITY AND CLIMATE RISK (SCR) PROFESSIONAL, PASSIONATE ABOUT SUSTAINABLE ENERGY CONSUMPTION AND CLIMATE CHANGE