The limits of our planet

Image result for From ocean to ozone, the limits of our planet


The population of vertebrate species on Earth in the wild saw a dramatic fall of about 30% between 1970 and 2006, with the worst effects being in the tropics and in freshwater ecosystems. Destruction of species’ habitats by pollutants and land-use change are destroying flora and fauna at unprecedented rates. In fact, the ecological footprint of humanity — the natural habitats, such as water and land, transformed or destroyed as a result of human activity — far exceeds the biological capacity of the earth.

Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change.

What is Ecological footprint of humanity and Biocapacity?

The ecological footprint measures human demand on nature, i.e., the quantity of nature it takes to support people or an economy

  • It is a measure of human impact on Earth’s ecosystemand reveals the dependence of the human economy on natural capital.
  • The ecological footprint is defined as thebiologically productive area needed to provide for everything people use: fruits and vegetables, fish, wood, fibres, absorption of carbon dioxide from fossil fuel use, and space for buildings and roads.
  • Biocapacity is the productive area that can regenerate what people demand from nature.
  • Ecological footprint and biocapacity can be compared at the individual, regional, national or global scale.
  • Both footprint and biocapacity change every year with number of people, per person consumption, efficiency of production, and productivity of ecosystems.
  • Ecological footprint analysis is widely used around the Earth in support of sustainabilityassessments.

From 1961 to 2010, Ecological Footprint accounts indicate that human demand for renewable resources and ecological services reaching a point where the planet’s bio productive area is no longer sufficient to support the competing demands.

What is a safe operating space for humanity and Planetary Boundaries?pexels-photo-60132.jpeg

Although Earth has undergone many periods of significant environmental change, the planet’s environment has been unusually stable for the past 10,000 years. This period of stability — known to geologists as the Holocenehas seen human civilizations arise, develop and thrive.

Such stability may now be under threat. Since the Industrial Revolution, a new era has arisen, the Anthropocene, in which human actions have become the main driver of global environmental change. This could see human activities push the Earth system outside the stable environmental state of the Holocene, with consequences that are detrimental or even catastrophic for large parts of the world.

During the Holocene, environmental change occurred naturally and Earth’s regulatory capacity maintained the conditions that enabled human development. Regular temperatures, freshwater availability and biogeochemical flows all stayed within a relatively narrow range. Now, largely because of a rapidly growing reliance on fossil fuels and industrialized forms of agriculture, human activities have reached a level that could damage the systems that keep Earth in the desirable Holocene state. The result could be irreversible.

In an attempt to understand the natural world, its relationships with human societies and limits, in 2009, Johan Rockström and others from the Stockholm Environment Institute described elements of the biophysical world that link us together.  Often regarded as a “safe operating space for humanity”, these planetary boundaries include

  • loss of biodiversity,
  • land-use change,
  • changes to nitrogen and phosphorus cycles,
  • ocean acidification,
  • atmospheric aerosols loading,
  • ozone depletion,
  • chemical production,
  • freshwater use and
  • Climate change.

pexels-photo-288093.jpegThese Planetary boundaries define the safe operating space for humanity with respect to the Earth system and are associated with the planet’s biophysical subsystems or processes. If the Earth-system processes and associated thresholds which, if crossed, could generate unacceptable environmental change.

Biophysical considerations

Many of these conditions respond in a non-linear manner to changes. This means that ecosystems that are stressed by their exposure to pollutants may not recover once the pollutants are removed. When ecological thresholds or tipping points are crossed, significant large-scale changes may occur, such as breakdown of glaciers in Greenland and the Antarctica, the dieback of rainforests in the Amazon, or failure of the Indian monsoons.

Since these boundaries interact with one another and cause changes across scales, crossing a threshold in one domain can speed up or undermine processes in another subsystem.  Although the planetary boundaries are described in terms of individual quantities and separate processes, the boundaries are tightly coupled. For instance, greenhouse gas (GHG) emissions increase ocean acidification, land-use change often increases GHG emissions, and increasing nitrogen and phosphorus deplete species biodiversity and freshwater resources and increase warming from climate change.pexels-photo-311461.jpeg

The boundaries that are proposed represent anew approach to defining biophysical preconditions for human development. For the first time, quantified the safe limits outside of which the Earth system cannot continue to function in a stable, Holocene-like state

Planetary Boundaries and limits to growth

Various concepts exist to describe global environmental constraints: “carrying capacity”, “sustainable consumption and production”, “limits to growth”, “tipping points”, “footprints”, “safe operating space” or “planetary boundaries”. The concept of planetary boundaries which provides a powerful description of the global “adding-up” constraints across key dimensions

According to Mr. Rockström and others, we are already at critical levels of concern for climate change, fresh water, species biodiversity and changes to nitrogen and phosphorus cycles, which are reaching tipping points. For example,GHG emissions have led to average atmospheric carbon dioxide concentrations being about 410 ppm. This is well above the 350 ppm levelconsidered a ‘safe’ limit, and the earth is already about a degree Celsius warmer than average pre-industrial temperatures.

One may regard planetary boundaries as support systems for life on Earth or view them as expressing “carrying capacity” and defining “limits to growth”.

  • The latter is a thesis that was originally published nearly half a century ago by the Club of Rome as a book in 1972.
  • It described the situation we would find ourselves in with exponential population and economic growth.
  • While the “limits to growth” argument was challenged for good analytical reasons, it still provided a lens through which to view the changing world of the 21st century.
  • It also offered the idea of thinking about a system as a whole — systems thinking — not just as separate parts and feedback mechanisms as valuable processes in considering long-term change.

The significance of inter- linkages approach for sustainability

The idea of sustainability has been embedded in the human imagination for a very long time and is expressed through our ideas of nature, society, economy, environment and future generations. But it became formally a part of international agreements and discourse when it was recognised at the Earth Summit of 1992 in Rio de Janeiro.

Recently proposed Sustainable development goals (SDGs) include promoting inclusive and sustainable economic growth as well as wellbeing for all.  Economic activities ultimately depend on ecological assets and their capacity for provisioning primary resources and life supporting ecological services. Managing the latter is becoming a central issue for decision makers worldwide. Thus, living within the limits of the biosphere’s ecological assets is a necessary condition for global sustainability, which can bequantitatively measured and must be met to achieve SDGs.

The systems view and the recognition of inter-linkages among the social, environmental, and economic pillars of sustainability, and between biophysical planetary boundaries and social conditions, are essential to have a chance of keeping the world safe for future generations. It is telling that scholars who work on planetary boundaries regard climate change as one of the easiest to manage and contain. For that,

  • The world should live within the planetary boundaries through the deployment of new sustainable technologies and new global rules of the game.
  • An orderly and cooperative process will lead to dramatically improved outcomes for all parts of the world.
  • These transformations would only form a subset of a post-2015 agenda, since they do not fully address issues such as ending extreme poverty, gender equality, health, education

Needed a shared global framework

In the absence of a shared global framework individual countries fail to acknowledge planetary boundaries in national policymaking. They each scramble for scarce resources. Fossil fuel and food prices soar, and planetary boundaries are exceeded as the middle-income countries catch up with the high-income countries. The weakest countries find themselves pushed out of the marketplace and fail to develop. This zero-sum or negative-sum struggle can easily turn nasty. Richer countries will guard their advantage with military force if necessary

Rather than knowingly crossing the planetary boundaries, the world can agree and cooperate on living within the playing field they imply, by adopting improved technologies, stabilizing the world’s population, and protecting threatened species and ecosystems.

Placing the world on such a “Sustainable Development Trajectory,” must be a central objective of world nations.


In thinking about these planetary limits then, researchers and policymakers should reflect on multiple systems and the linkages among them, and whether step-by-step or transformative changes must be considered to keep the planet safe for the future.

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