Ecosystems are the foundation for human life. They perform a range of functions, generally referred to as environmental services, without which human societies and economies could not operate at their current level. We depend on them for air, water, food, shelter and energy. Local ecological collapse may have caused the end of a civilization on Easter Island. More recently, ecological collapse in and around the Aral sea has had dramatic social and economic consequences for the region. Ecosystems can tolerate a measure of impact from human use with no negative effects – an attribute generally known as resilience – but beyond a certain threshold, or tipping point, sudden, radical and sometimes irreversible disruption occurs. Soil quality, freshwater supplies and biodiversity diminish drastically, while agricultural capacity plummets and daily living conditions deteriorate significantly. Displaced populations and the loss of previous food sources add pressure to other areas, so that local disruption might escalate into the rapid and irreversible collapse of most ecosystems across the Earth, drastically compromising the planet’s capacity to support a large human population.
Since the mid 1950s, many elements that ensure the habitability of the planet are degrading at an accelerating pace.
Ecosystems are complex entities, which consist of a community of living organisms in their non-living environment, linked together through flows of energy and nutrients. The behaviour of an ecosystem is relatively stable over time, but when the balance between some of its elements is altered beyond a certain threshold, it can experience a non-linear, possibly catastrophic transformation.
Human-induced factors that affect ecosystem vitality may be classified in the following manner:
Scholars describe the current historical moment as the start of a new geological era, called the Anthropocene, where humans as the predominant agent of change at the planetary level change the nature of nature itself. Since the mid 1950s, many elements that ensure the habitability of the planet, whether greenhouse gas concentration, forested areas or the health of marine ecosystems, are degrading at an accelerating pace. In 2009, an international group of experts identified nine interconnected planetary boundaries that underpin the stability of the global ecosystem, allowing human civilization to thrive. Their report indicates that we have exceeded safe limits for four of those, and are now operating in a high-risk zone for biosphere integrity and biogeochemical flows. Unless we rapidly change trends and adopt a new sustainable paradigm, we are very likely to exceed all nine boundaries, and leave the safe operating ecological space where humanity has thrived.
Unless we rapidly change trends we are very likely to leave the safe operating ecological space where humanity has thrived.
Nauru, a small island in the central Pacific, provides a telling example of the risks and consequences of ecological collapse. The mining of rich phosphate resources placed this island-nation among the wealthiest in the world in the 1970s, but it resulted in a severe degradation of the island’s ecosystem. Many key plant and animal species are now either extinct or endangered, previously rich and abundant food sources such as pandanus fruits, almonds and noddy birds have been destroyed, and 40% of Nauru’s coastal marine life was devastated by run-off from the mines. With no topsoil left to restore a once thick tropical forest in the mined-out island core, Nauruans are no-longer self-sufficient on their island home.
Associate Professor of Global Governance and Director, Center for Governance and Sustainability, University of Massachusetts Boston; Global Challenges Foundation Ambassador
Research Fellow, Natural Resources and Ecosystems, Stockholm Environment Institute