Sustainability definitions
The following definitions allow us to have a common language around sustainability and climate change issues.
Adaptation, adaptive capacity and resilience
Adaptation is how an affected system or environment changes to continue functioning satisfactorily. Adaptation in response to climate change impacts can be made by humans, other animals, plants or whole ecosystems. They can be deliberate and planned, unconscious or evolutionary.
To respond to the consequences of climate change, the need for adaptation in human settlements is inevitable, for example planting low water use (xeriscape) gardens. Adaption may be changes to behaviours or to places, for example altering the built environment through retrofitting and redesign to reduce greenhouse gas emissions.
Adaptive capacity means the ease and ability of a human or natural system to adjust to changes and cope with the consequences. Though human adaptive responses are possible at both individual and collective levels, adaptive capacity tends to refer to the larger scale of community, city and nation.
Generally, resilience is the extent to which a system can spring back to its usual dimensions or characteristics after being subjected to a pressure—for example, how an area of bushland regenerates after fire. It assumes a stable baseline will be re-established.
However, in the case of climate change, the baseline is changing and so resilience is better characterised as the ability of a system to continue operating under circumstances of change. For example as a place gets drier, managing the water supply to sustain the desired quality of life.
Biodiversity and ecosystem services
Biological diversity (biodiversity) is the variety of life on earth and comprises countless species living in their different but inter-dependent ecosystems. Each ecosystem has evolved to require certain ‘services’ to keep functioning, for example water, food, air, and this includes seasonal (climatic) variability.
Cities and the organisms within them, also need such ecosystem services for healthy survival, for example, clean air, fresh water and soil for growing food and fibre. However, most ecosystem services of cities are provided from the hinterland outside its boundaries, for example from the surrounding farmland or bushland.
Biosequestration
Biosequestration means removing greenhouse gases from the atmosphere and storing them using biological processes, for example growing trees to store carbon or enhancing soil carbon through agricultural practices.
Climate and climate change
The world’s climate is continually changing in geological time due to changes in global processes at large scales (global and continental) and due to factors (latitude, topography) and abiotic (non-living) processes such as ocean currents and winds. The climate in this Holocene era (from 10,000 years ago to present) is different from previous eras.
Climate is both a personal perception of place for example ‘Alaska has a harsh climate’ and ‘South East Queensland is pleasant all year round’, and meteorological patterns and variables (rainfall, wind, temperature, sunshine, humidity) for example Alaska has a cold, sub-arctic climate and South East Queensland has a warm sub-tropical climate.
The debate around climate change is about how much human activity is influencing these natural processes of change, both directly and indirectly, and is referred to as ‘anthropogenic forcing’.
Exposure, vulnerability, risk and impact
Exposure means the populations that are more exposed, or more sensitive to, a risk. For example, a community in a low lying coastal area may be more exposed to the risk of flood.
According to the International Panel on Climate Change (IPCC), ‘Vulnerability is the degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes’.
Vulnerability is a combination of factors, some of which can be managed and some of which cannot. It is a qualitative assessment of potential harm and not a scientifically proven prediction.
Risk occurs when there is a threat of alteration or damage to something that is valued by all or part of a community for example, a place or a species.
Risk can be understood in terms of frequency (or the likelihood) of a particular event and its consequences. For example, flood risk is assessed by average recurrence interval and there is a different level of risk between a one-in-ten-year flood and a one-in-one-hundred-year flood.
Impact refers to the likely effect on a place and/or a community of a particular event. In other words, it is the consequence of a risk being realised. Impacts vary from mild to catastrophic. Many people are aware of risk and impact through bushfire warning systems and cyclone risk rating systems.
Understanding the vulnerability of a community includes estimating the risk and impact of an event. However, within an existing human community the most vulnerable - the very old, the very young, the chronically ill, the homeless, and people on low incomes - are generally likely to be at higher risk from climate change.
Greenhouse and enhanced greenhouse effects
The greenhouse effect is where the gases in the earth’s atmosphere, such as water vapour, carbon dioxide, ozone and methane, function in a similar way to the glass of a greenhouse. When sunlight penetrates the ‘glass’ (the earth’s atmosphere) it warms the interior and the heat is trapped. Without this phenomenon, our climate would be too cold to sustain our current ecosystems. However, you can have too much of a good thing.
The enhanced greenhouse effect refers to the way human activities exacerbate the warming effect—for example, the release of the by-products of human activity like carbon dioxide and methane into the atmosphere at a rate exceeding natural processes.
Mainstreaming
Mainstreaming is when a concept is accepted so that it is incorporated in thinking and decision making. For example, accepting that all planning decisions should consider sustainability as an underlying requirement would be mainstreaming of sustainability.
Mitigation
Mitigation refers to actions which address the causes of a problem. Using a common medical analogy, prevention of disease (for example, through vaccination or healthy living) is better than cure (using medicines and hospitals).
To mitigate climate change requires human intervention to reduce the production of greenhouse gas emissions or to remove them from the atmosphere. For example, reducing energy consumption at home and at work is a mitigating action.
Precautionary principle and the ‘no regrets’ strategic approach
Many definitions of the precautionary principle exist, but all share the need by decision makers to anticipate harm before it occurs and to take action to prevent or minimise such harm, even without scientific certainty.
The precautionary principle is most often applied to human actions on the environment and on human health, as both are complex systems often with unpredictable consequences. The implicit ethical responsibility to maintain the integrity of natural systems demands the precautionary principle be continually applied.
A globally accepted definition from the 1992 Rio Declaration states, ‘…full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation’. This use of ‘cost-effective measures’ indicates that costs can be considered. This is different from a no regrets approach which ignores the costs of preventative action.
To achieve outcomes without the risk of later ‘regret’, requires a strategic approach to policies and decisions that fully considers the future consequences.
Sustainability and ecologically sustainable development (ESD)
Sustainability means resolving the often competing goals between economic prosperity, cultural diversity, social equity and environmental quality. Applying sustainability outcomes is commonly referred to as triple or quadruple bottom line.
The ACT Government has adopted the definition of sustainable development from the Brundtland Report of 1987: ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’.
Australia's National Strategy for Ecologically Sustainable Development 1992 (NSESD) defines ecologically sustainable development as 'using, conserving and enhancing the community's resources so that ecological processes, on which life depends, are maintained, and the total quality of life, now and in the future, can be increased'.
Synergistic effects
Synergy is where the combined effect of interaction of two or more things is enhanced. A combination of environmental factors can greatly increase the impact of a natural disaster. For example, a king tide combined with a category five cyclone greatly increases the probable impacts of flooding that each would have individually.
With climate change, the uncertainty around the scale of impacts and the combinations of effects means that synergistic effects should be taken seriously. For example, the combination of changed rainfall patterns and higher evaporation rates has important implications for surface run-off and therefore water supply.
Systems or metabolism approach
Living organisms evolve over time by adapting to complex environmental changes. Just like organisms, cities are complex systems that are synergistic with, and inter-dependent on, their surrounds. Adopting a systems approach ensures that simplistic and linear thinking about the evolution of cities is not applied.
The metabolism approach to urban planning extends this, to better understand the complexity of systems that operate within human settlements. The metabolism of a living organism is the processes and chemical changes which it needs to sustain and reproduce itself. The concept of urban metabolism helps us understand how cities use resources, energy and land, all elements of the environmental system, to maintain and reproduce themselves.
In urban planning, this approach ensures that sufficient consideration is given to what the city needs to make it function well and prosper, recognising the importance and context of its surroundings
