Globalisation, Economic Transition and the
Environment
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10. Planetary boundaries: using early
warning signals for sustainable
global governance1
Will Steffen, Johan Rockström,
Ida Kubiszewski, and Robert Costanza
THE CHALLENGE
Over the past half-century, we have become adept at dealing with environmental problems at the local and regional scales. The worst excesses of the
industrial revolution have, in many cases, been ameliorated. Rivers, such
as the Thames in London, have been cleaned up and major urban airsheds,
such as the Los Angeles basin, are now experiencing vastly improved air
quality. DDT has been banned in most developed countries, and lead has
been removed from petroleum-based fuels. These impressive successes
have been celebrated in many quarters, perhaps most notably in Bjorn
Lomborg’s book, The Sceptical Environmentalist (Lomborg, 2001).
However, to say we have done enough globally would be false on
two counts. Firstly, while these problems have been addressed in many
European and North American nations, over three-quarters of the world’s
people do not live in developed countries. For them, many of the local and
regional environmental problems still exist and, in many cases, are worsening. Secondly, the environment – our life-support system – is under increasing threat from a wide range of human pressures, many of them emanating
from high consumption levels in wealthy countries. The deterioration of
the global environment puts even more pressure on the poorest countries to
limit growth, even as they struggle to bring their populations out of poverty.
This is an entirely new situation for humanity. In the past, when we
fouled our local environment, we could move to someplace else. However,
as the human population has grown, this short-term solution has been
rendered unviable. Furthermore, the impacts of our presence have rarely
been felt beyond our immediate surroundings. This is no longer the case.
The global environment has provided an especially accommodating environment over the past 12,000 years for humanity to develop and thrive
259
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(Costanza et al., 2007). But the world population is no longer small,
sparsely dispersed, and technologically limited. Humankind’s aggregate
impact on the natural environment is intensifying.
Does our planet have boundaries regarding the amount of growth in the
material economy that it can absorb? We believe it does and that certain
preconditions must be set that acknowledge and respect these boundaries.
This situation is captured in the concept of the Anthropocene, a newly
defined geological era beginning around the 1800s in the form of the
Industrial Revolution. The term was introduced and popularised by
Nobel Laureate Paul Crutzen (Crutzen, 2002), who felt the recent influence of human activity on the Earth was significant enough to warrant
the naming of a new epoch. The past 12,000 years or so has been a period
defined by geologists as the Holocene, an epoch in which global average
temperatures have been remarkably stable and during which agriculture
and complex societies first emerged and flourished in Africa, Asia, South
and Central America, and the Mediterranean region.
Since the Industrial Revolution, the human enterprise has expanded so
rapidly that we are now overwhelming the capacity of the Earth system
to absorb our wastes and to sustainably provide the ecosystem services
we require. In the period since the Second World War, the acceleration
of development has become particularly dramatic. Humanity is fundamentally changing the Earth’s physical climate (International Panel on
Climate Change (IPCC), 2007), overwhelming its capacity to provide
ecosystem services, homogenising its biological diversity (Millennium
Ecosystem Assessment (MEA), 2005), and substantially modifying the
global cycles of critical elements like nitrogen, carbon, and phosphorus
(Steffen et al., 2004). We are indeed passing through the exit door of the
Holocene and into the unknown world of the Anthropocene.
In this chapter, we present the concept of planetary boundaries for
estimating a safe operating space for humanity with respect to the functioning of the Earth system. We make a preliminary effort at identifying
key Earth-system processes and attempt to quantify for each process the
boundary level that should not be transgressed if we are to avoid unacceptable global environmental change. Unacceptable change is here defined in
relation to the risks humanity faces as the planet moves further away from
the accommodating environment of the Holocene.
THE CONCEPT OF PLANETARY BOUNDARIES
Although we are building on earlier efforts to limit human impacts on the
environment, the concept of planetary boundaries outlined in this chapter
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takes a rather different approach, more fully described in Rockström et al.
(2009a, 2009b) and Steffen et al. (2011). It does not focus directly on the
human enterprise but rather emphasises the Earth as a complex system.
We identify nine areas that are most in need of set planetary boundaries:
(i) climate change; (ii) biodiversity loss; (iii) excess nitrogen and phosphorus production, both of which pollute our soils and waters; (iv) stratospheric ozone depletion; (v) ocean acidification; (vi) global consumption
of freshwater; (vii) change in land use for agriculture; (viii) air pollution;
and (ix) chemical pollution.
These nine areas are biophysical processes of the Earth system that
determine the self-regulating capacity of the planet. Table 10.1 lists all
nine identified areas and the proposed boundaries of seven of them (two
are still in the process of being determined). Exceeding the thresholds
may trigger non-linear changes in the functioning of the Earth system,
thereby challenging social-ecological resilience at regional to global scales.
Together, the set of boundaries represents the dynamic biophysical ‘space’
of the Earth system within which humanity has evolved and thrived. The
boundaries respect Earth’s ‘rules of the game’ or, as it were, define the
‘planetary playing field’ for the human enterprise. These boundaries, as
thresholds in key Earth-system processes, exist irrespective of people’s
preferences and values, or, for that matter, perceived compromises based
on political and socioeconomic feasibility, such as expectations of technological breakthroughs and fluctuations in economic output (real GDP).
As can be seen from Table 10.1, three planetary boundaries have already
been transgressed and four boundaries are fast being approached.
The position of these boundaries corresponds to the lower end of the
uncertainty zone. This is a conservative, risk-averse approach to quantifying our planetary boundaries that takes account of the large uncertainties
that surround the true position of many thresholds.
The planetary boundaries approach rests on three branches of scientific
inquiry:
1.
2.
The first addresses the scale of human action in relation to the capacity of the Earth to sustain it. This is a significant feature of the ecological economics research agenda (Costanza, 1991), which draws on
work on the essential role of the life-support environment for human
well-being (Odum, 1989; Vitousek et al., 1997) and on the biophysical constraints that limit the expansion of the economic sub-system
(Boulding, 1966; Arrow et al., 1995).
The second is the work that has been undertaken to understand essential Earth-system processes (Bretherton, 1988; Schellnhuber, 1999;
Steffen et al., 2004), including human actions (Clark and Munn, 1986;
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Table 10.1
Proposed planetary boundaries, including current status and
pre-industrial value
Earth-system
process
Parameters
Proposed Current
Preboundary status industrial
value
Climate change
(i) Atmospheric concentration
of carbon dioxide (parts per
million, by volume)
350
387
280
(ii) Change in radiative forcing
(watts per square metre)
1
1.5
0
Rate of
biodiversity loss
Extinction rate (number of
species per million species per
year)
10
.100
0.1–1
Nitrogen cycle
(part of a
boundary with the
phosphorus cycle)
Amount of N2 removed from
the atmosphere for human use
(millions of tonnes per year)
35
121
0
Phosphorus
cycle (part of a
boundary with the
nitrogen cycle)
Quantity of P flowing into the
oceans (millions of tonnes per
year)
11
8.5–9.5
~1
Stratospheric
ozone depletion
Concentration of ozone
(Dobson unit)
276
283
290
Ocean
acidification
Global mean saturation state of
aragonite in surface sea water
2.75
2.90
3.44
Global freshwater
use
Consumption of freshwater by
humans (km3 per year)
4,000
2,600
415
Change in land use
Percentage of global land cover
converted to cropland
15
11.7
Low
Atmospheric
aerosol loading
Overall particulate
concentration in the atmosphere,
on a regional basis
To be
determined
Chemical
pollution
For example, the amount
emitted to, or concentration of,
persistent organic pollutants,
plastics, endocrine disrupters,
heavy metals, and nuclear waste
in the global environment, or
the effects on ecosystem and
functioning of the Earth system
thereof
To be
determined
Source: Steffen et al., 2011.
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Turner et al., 1990), that have been brought together as part of the
evolution of global change research toward Earth-system science and
the development of sustainability science (Clark and Dickson, 2003).
The third is the framework of resilience (Holling, 1973; Gunderson
and Holling; 2002; Walker et al., 2004; Folke, 2006) with its links to
both complex dynamics (Kaufmann, 1993; Holland, 1996) and the
self-regulation of living systems (Lovelock, 1979; Levin, 1999). This
third framework emphasises multiple basins of attraction and threshold effects (Scheffer et al., 2001; Folke et al., 2004; Biggs et al., 2009).
CRITICAL FEATURES OF THE PLANETARY
BOUNDARIES CONCEPT
Earth system science is still in its infancy and much more needs to be
known. Nevertheless, we currently understand enough about the functioning of the Earth system to know that we must respect the hard-wired limits
of our own life-support system. Moreover, we must find practical ways to
respect these limits.
The planetary boundaries approach is one way, but it is still very much
a proof-of-concept approach. Much more work is required to refine and
operationalise it. The proposed boundaries in Table 10.1 are a preliminary
estimate. For some boundaries, the zone of uncertainty is still huge, and
for two of them – atmospheric aerosol loading and chemical pollution –
we are unable to make even a first, rough guess at where the boundary
might lie. In fact, we are not even sure that these nine boundaries are sufficient to define the planetary playing field. More may be needed.
Several features of the planetary boundaries conceptual framework are
critical to understanding how the approach works.
Scale
Because of the strong focus on the global scale and the scale of systems
immediately below it – such as the Earth’s continents and ocean basins –
the planetary boundaries approach raises issues of a cross-scale nature. As
noted earlier, we are interested in local and regional environmental issues
only insofar as their aggregate impact can affect the functioning of the
Earth system at the larger scales. However, the Earth’s surface, and by this
we mean the terrestrial surface and ocean basins, is very heterogeneous in
character. Consequently, change in one place is not necessarily equivalent
to a similar change in another place. This is particularly important for the
interactions among boundaries.
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The global hot-spots of biodiversity comprise a well-known example of
the implications of this heterogeneity. Conversion of a tropical rainforest
to cropland, which directly influences the land-use change boundary, can
have a much greater effect on the biodiversity boundary than the conversion of the same area of temperate grassland to a cropland. Similarly, the
same amount of freshwater used for human consumption can have quite
different effects on land-use change and biodiversity depending on the
source of the water and the nature of the irrigation system used. Even
more subtly, different patterns of the same type and overall area of landuse change – say, from forest to cropland – can affect biodiversity very
differently depending on the nature of the fragmentation pattern created.
The list of such heterogeneities could go on. The point is that the nature
of the changes at the fine scales occurring well below the larger scales of
interest can become important for the planetary boundaries approach,
particularly when these smaller-scale processes are aggregated back up to
continental, ocean basin, or global scales. From the examples cited above,
dealing with these cross-scale interactions may appear hopelessly complicated. However, new approaches, such as the fine-grained land architecture concept (Turner, 2009), may offer an efficient way to deal with the
interactions between the land-use change boundary and other boundaries
at a variety of scales.
There is ample evidence from local to regional-scale ecosystems, such as
lakes, forests, and coral reefs, that gradual changes in certain key control
variables (e.g., biodiversity, harvesting, soil quality, freshwater flows, and
nutrient cycles) can trigger an abrupt system state change when critical
thresholds have been crossed (Carpenter et al., 2001; Folke et al., 2004;
Hughes et al., 2007; Scheffer, 2009). More research is urgently needed on the
dynamics of thresholds and feedbacks that operate at continental and global
scales, especially for slow-changing control variables, such as land use and
land cover, water resource use, rates of biodiversity loss, and nutrient flows.
Here, we distinguish between: (i) identifiable planetary thresholds driven
by systemic global-scale processes which have a ‘top-down’ impact on subsystems; (ii) thresholds that may arise at the local and regional scales, which
become a global concern at the aggregate level if occurring in multiple locations simultaneously; and (iii) situations where gradual aggregate impacts
may increase the likelihood of crossing planetary thresholds in other Earthsystem processes, thus having a ‘bottom-up’ effect on the Earth system.
Interactions Among the Boundaries
Interactions among planetary boundaries may shift the safe level of one
or several boundaries, which we have provisionally set under the (strong)
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assumption that no other boundaries are transgressed. There are cascading impacts in which transgressing one boundary can have implications
for other boundaries. Even small changes can have a synergistic effect
when linked to other small changes. For example, conversion of forest
to cropland, increased use of nitrogen and phosphorus fertilisers, and a
larger extraction of freshwater for irrigation can collectively act to reduce
biodiversity much more than if each of these variables is acting independently. This is because many changes feed back into each other. The
processes involving ocean acidity and atmospheric carbon dioxide (CO2)
concentration are an example of a reinforcing feedback loop. An increase
in ocean acidity reduces the strength of the ‘biological pump’ that removes
carbon from the atmosphere, which increases the atmospheric concentration of CO2. This magnifies the physical uptake of CO2 by the ocean,
which further increases ocean acidity, and so on.
Tropical forests are a key component of both regional and global
energy balances and hydrological cycles. In the Amazon basin, a significant amount of water in the atmosphere is recycled through the vegetation. In addition, the forest produces aerosol particles that can form
cloud droplets. Changing particle concentration influences how likely the
clouds are to produce rain and the strength of the convective circulation.
Deforestation and biomass burning associated with dominant land-use
practices have changed convection and precipitation over the Amazon
basin (Andreae et al., 2004). These changes in precipitation complete a
feedback loop because the availability of water influences the amount
and kind of aerosol particles that the vegetation emits (Kesselmeier et
al., 2000). Such interacting processes driven by change in land use and
climate could reach a tipping point where the Amazon forest is replaced
by savanna-like vegetation by the end of the 21st century (Nepstad et al.,
2008).
This feedback loop is not limited to regional effects – it can also influence surface temperatures as far away as Tibet. Model simulations predict
that large-scale deforestation in the northern Amazon could drastically
change the surface energy balance, leading to a weakening of deep convection (Snyder et al., 2004a; Snyder et al., 2004b). This, in turn, would
drive a weakening and northward shift in the Inter-Tropical Convergence
Zone, which causes changes in the jet stream that directs the trajectory
of mid-latitude weather systems. This would ultimately influence surface
temperature and precipitation in Tibet.
Changes in climatic conditions in Tibet directly affect much of Asia’s
water resources. The 15,000 glaciers in the Himalaya-Hindu Kush region
store an estimated 12,000 km3 of freshwater, which is a main source of
freshwater for roughly 500 million people in the region, plus an additional
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250 million people in China (Cruz et al., 2007). Glacier melting, initially
causing short-term increases in runoff, leads to increased flood risks, seasonal shifts in water supply, and increasing variability in precipitation.
Although the calculated land-cover changes discussed here are extreme,
the results illustrate that changes in the global climate system driven by
land-use change in one region can affect water resources in other parts of
the planet.
Although we have not systematically analysed the interactions among
planetary boundaries, the examples we present suggest that many of
these interactions will reduce rather than expand the boundary levels we
propose, thereby shrinking the safe operating space for humanity. This
suggests the need for extreme caution in approaching or transgressing any
individual planetary boundaries.
Resource Use, Affluence, and Human Population Size
Many other approaches to managing global change more explicitly deal
with the human enterprise itself, especially in terms of resource use. The
planetary boundaries approach leaves the thorny issues of population size,
affluence, equity within and between countries, technologies, resource use,
and pollution management as variables that can be traded off in infinite
combinations depending on the socio-economic systems, cultures, and
worldviews of groups of humans. The only requirement is that the aggregate outcomes of the human enterprise as a whole must be such that the
critical control variables stay within the set of planetary boundaries.
The I 5 PAT identity (Ehrlich and Holdren, 1971) can provide a simple
conceptual tool for analysing trade-offs within the human enterprise. Here
I denotes Impact, and can be defined as the globally aggregated impact
on an Earth-system process in terms of its control variable. The value of
I should not exceed the value of the planetary boundary. Beyond that,
however, there is a very wide range of combinations of P (Population),
A (Affluence), and T (Technology) that can keep the human enterprise
within the boundary for I. A low human population would, for example,
allow for higher affluence per capita and perhaps more flexibility in the
technologies employed to generate that affluence. On the other hand, a
much higher human population coupled with high and rising affluence
per capita would place enormous demands on technology to maintain a
global impact within the boundary value. This is, in fact, the situation that
humanity finds itself in now.
A further point concerning the IPAT framework is that the planetary
boundaries approach is only concerned with ensuring that the impact
remains within the boundary. It says nothing about the distribution of
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affluence and technologies among the human population. For example, it
is possible that a ‘fortress world’, in which there are huge differences in the
distribution of affluence, and a much more egalitarian world, where socioeconomic systems are designed to share wealth more equitably, could
equally satisfy the planetary boundary conditions. They would, however,
deliver vastly different outcomes for human well-being.
THE IMPLICATIONS FOR GOVERNANCE
As a practical solution for living sustainably in the modern era, the planetary boundaries approach raises important questions and opportunities for governance and institutions, even to the point of challenging the
concept of national sovereignty. We have identified four specific challenges for governance (Young and Steffen, 2009).
Early-Warning Systems
The nature of Earth-system dynamics – nonlinearities, tipping elements,
and thresholds/abrupt changes – strongly suggests that humanity needs
a system to warn us when we are approaching potentially catastrophic
threshold points. Indeed, the planetary boundaries approach is based
directly on this feature of the Earth system. An early-warning system
is a prerequisite for being able to recognise and steer away from such
thresholds.
Some recent research using a complex systems framework offers hope
of finding a reliable biophysical basis on which to build an early-warning
system (Scheffer et al., 2012). Such analyses are pointing to empirical
indicators of the proximity of complex systems to critical thresholds that
could serve as a means of anticipating abrupt system change. It is well
known that as a system approaches a key threshold, its capacity to recover
from a small perturbation begins to decline, since it becomes less resilient.
Hence, the rate of recovery slows down. This is sometimes referred to as
‘critical slowing down’ (Scheffer et al., 2012). Indicators that reveal the
rate of system recovery therefore offer a potential foundation upon which
to create early-warning systems.
Dealing With Uncertainties
Each of the planetary boundaries is placed within a zone of uncertainty,
some much larger than others. Although further scientific research will
reduce these uncertainties in many cases, they will never be completely
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eliminated. In an adversarial political environment, uncertainties can be
exploited as reasons for inaction. Hence, scientists must be able to address
uncertainty without being attacked or scapegoated.
Because the environmental problems that society is currently dealing
with are highly complex and feature nonlinear and often abrupt changes,
a successful governance system (i.e., one capable of offering viable solutions to these problems) must be able to concurrently make decisions
involving extreme uncertainty and respond in an adaptive manner as new
information becomes available. Given the need to recognise and coexist
with a certain level of uncertainty, global governance systems will need to
emphasise and adopt a precautionary approach when determining where
humanity should operate with respect to each of the planetary boundaries.
Multi-Level Governance
As the human impact on the environment extends to the global level, the
creation of institutions with the capacity to implement viable solutions on
the same scale is key. However, interaction with the more traditional institutions that currently exist at national, sub-national, and local levels will
be critical, and will require a complex network of cross-level interaction.
Often global environmental developments, such as climate change, can
impact on social welfare at local levels. Similarly, local developments can
have significant effects on the global scale, such as the contribution of
deforestation to global concentrations of CO2. Such varying interactions
will require various forms of multi-level governance. Furthermore, it will
require distinct arrangements operating at different levels of social organisation that interact in a mutually reinforcing manner to provide effective
Earth-system governance. Creating such multi-level governance systems
will be especially important for those planetary boundaries that are based
on aggregates of many local and regional actions.
Governance can address specific problems, such as climate change and
biodiversity loss, through two approaches that can turn general objectives
like sustainable development into well-defined and operation goals in
specific cases.
1.
The first approach involves turning general goals and problems into
specific measures and boundaries at an operational level. For example,
it is possible to define a climate change boundary of no more than 450
parts per million (ppm) of CO2 in the atmosphere or to define a goal in
the form of halving the number of people without safe drinking water
by 2015 as spelled out by the UN Millennium Development Goals.
Scientific knowledge and the ability to pursue these goals actively and
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269
effectively must be a critical aspect of setting such specific and defined
goals.
The second approach involves creating safeguards to prevent or
control runaway processes like abrupt disintegration of ice sheets or
financial panic. This will require a strengthening of adaptive capacity
with regard to issues like climate change and the creation of countercycling mechanisms to prevent positive feedback loops. These types
of approaches are adopted regularly at national levels through, for
example, the creation of mechanisms to prevent an escalating financial crisis, which is achieved by emphasising prevention and preparedness as well as emergency response preparedness to extreme events like
hurricanes or tsunamis. Global society now needs to develop similar
preparedness mechanisms at the global level.
Capacity to Assimilate New Information
In addition to reducing the zone of uncertainty for some boundaries,
scientific research will continue to uncover more insights into the dynamics of the Earth system itself. This could lead to the need for additional
planetary boundaries or the reformulation of existing ones. The increasing
flow of new scientific information will undoubtedly put pressure on any
institutional framework to keep up with the pace of new knowledge. A
case in point is the debate over what quantity of greenhouse gases can be
released without disastrous effects. After a long time trying to convince
the international community that the climate change boundary should
be an atmospheric concentration of 450 ppm of CO2, a growing number
of scientists are suggesting that a 350 ppm boundary would be more
appropriate.
Acknowledging the End Goal
Staying within the planetary boundaries is not a goal in itself, but is a
necessary condition for achieving the ultimate goal – the improvement of
sustainable human well-being. Well-being is created through the satisfaction of fundamental human needs, including such basics as shelter, food,
and water, but also good health, time with friends and family, education,
fairness, a sense of security, freedom, and a healthy natural environment
capable of providing a range of ecosystem services (Costanza et al., 2007).
Exceeding planetary boundaries will ultimately have consequences for
society by reducing the overall quality of life.
For example, as the climate change boundary is exceeded, more severe
weather events are likely to occur. Such variability and uncertainty will
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Chemical
pollution
(not yet
quantified)
Climate
change
Atmospheric
aerosol loading
(not yet quantified)
Ocean
acidification
Stratospheric
ozone depletion
Biodiversity
loss
Change in
land use
Global
freshwater
use
BiogeoBiogeo- chemistry:
chemistry: Nitrogen
Phosphorus cycle
cycle
Sources: Planetary boundaries: Steffen et al., 2011; well-being: as developed by Oxfam
(Raworth, 2012).
Figure 10.1
Planetary boundaries diagram overlaid with an inner
boundary of elements of sustainable human well-being
decrease our overall sense of security and, in certain cases, will also impact
on our physical security by endangering our shelter, food, and water.
Figure 10.1 is the planetary boundaries diagram (Steffen et al., 2011)
overlaid with an inner boundary of elements of sustainable human wellbeing as developed by Oxfam (Raworth, 2012). This creates a sustainable
‘doughnut’ which brings together the biophysical boundaries with the
social boundaries to create a safe and sustainable space in which humans
can thrive.
Ultimately, there will need to be institutions operating, with authority, above the level of individual countries to ensure that the planetary
boundaries are respected. In effect, such institutions, acting on behalf of
humanity as a whole, would be the arbiter of the myriad trade-offs that
need to be managed as nations and groups of people jockey for economic
and social advantage. It would, in essence, become the global referee
on the planetary playing field. While humanity is still a long way from
meeting this challenge, some creative thinking about new institutions is
showing some promise. For example, one proposed institution that moves
in this direction is the concept of an Earth Atmospheric Trust (Barnes et
al., 2008), which would treat the atmosphere as a global common property
asset managed as a trust for the benefit of current and future generations.
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SUMMARY AND CONCLUSIONS
Earth system science is still in its infancy and much more needs to
be known to create robust solutions to humanity’s global dilemmas.
Nevertheless, we know enough now about the functioning of the Earth
system to recognise that we must learn to respect the hardwired limits
of our life-support system. We must also find practical ways to respect
those limits. Much more work is required to refine the concept of planetary boundaries and make it operational. The nine proposed boundaries
outlined here are a preliminary estimate. For some of the boundaries, the
zone of uncertainty is still huge, and for two of them – atmospheric aerosol
loading and chemical pollution – we are unable to make even a first, rough
guess at where the boundary might lie. In fact, we are not even sure that
these nine boundaries are sufficient to define the planetary playing field.
More may be needed.
Just when we are developing some solutions for environmental problems at the local and regional scales – at least in developed countries – we
are confronted with the challenge of environmental problems of a more
complex nature at the global scale. Climate change is just the tip of the
proverbial iceberg, with many more linked environmental, socioeconomic,
and cultural changes sweeping rapidly across the planet.
Effective solutions for living sustainably in the post-industrial age
require innovative frameworks and implementation strategies. Rather
than tackling these global-scale problems one by one, as we are attempting to do with respect to climate change, we need a far more holistic and
integrated approach. The planetary boundaries framework provides such
an approach.
Within the boundaries of the planetary playing field, there are an infinite number of strategies, tactics, and trade-offs that humanity can deploy
as it continues to strive to improve human well-being. The rules of the
game are familiar – economics, trade, laws and regulation, ethics, local
and regional environmental protection, and so on, are recognisable to us
all. What is new is that the playing field for this game is not infinite. It has
boundaries and the players must respect these boundaries.
Implementing the concept of planetary boundaries presents huge challenges for global governance and institutions. Science is well on the way to
defining the planetary playing field, but we have yet to define the roles of
the global referees and grant them the authority to keep the players on the
field. Respecting the boundaries means respecting the global commons –
the atmosphere, oceans, and ecosystem functioning and the services
derived from that functioning. The solution, as Peter Barnes has suggested (Barnes et al., 2008), is to greatly expand the ‘commons sector’ of
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the global economy by establishing institutions with the capacity to keep
humanity within a safe operating space. These new kinds of commons
institutions need to be developed at multiple scales, from local to global,
with full participation of the affected stakeholders.
NOTE
1. This chapter is based on the following papers: ‘How defining planetary boundaries
can transform our approach to growth’ (Steffen et al., 2011); ‘Planetary boundaries:
exploring the safe operating space for humanity’ (Rockström et al., 2009a); and ‘A safe
operating space for humanity’ (Rockström et al., 2009b). See these papers for a complete
description of the planetary boundaries.
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