Towards Sustainability of the Earth System

Earth system is endowed with unique characteristics and geophysical conditions to support life [1] and ecosystem services. Its ecological and social subsystems, individual processes, and their interactions forming the earth system determine the fate of biota and humans [2]. While the earth system has survived for billions of years, the Holocene era has seen unprecedented impacts from an anthropogenic influences [3], some have called this an anthropogenic era [4]. Climate change and rapid resource use to feed the burgeoning population are changing the nature and stability of the earth system. Current levels of human impacts can inadvertently alter the earth system in ways that it may prove irreversible [5]. Some examples of these impacts are Atlantic thermohaline circulation, Amazon forest dieback, and decay of Greenland ice sheet [6].

Continuation of status quo levels of resource use and environmental impacts without consideration of system limits [7] can lead to unsustainable trajectories of the earth system. The need to understand and work within the limits imposed by natural systems for achieving growth is a major emphasis in achieving sustainability of the earth system. This reflects the equilibrium that is within the boundaries of ecosystem services and the carrying capacity [8] of the earth system. The socioeconomic activities for human well-being need to balance with conservation of life support systems provided by the earth system [9].

The nature of limits and systems behavior of the earth system is often compared to managing a spaceship [10]. Under these conditions, resources used and waste generated have to be within the capacity of the earth system to provide the services. Excess and unmanaged impacts on the earth can result in failure of the earth system to sustain the multiple ecosystem services and biophysical processes. There is a critical need to further research into social and ecological aspects of natural systems [11] to achieve sustainability. Research and management at the intersection of global environmental change and sustainable development is an important dimension of sustainability [12].

The nature of the response of the earth system to shocks depends on the resiliency of the system [13] to absorb and adapt to new levels of stress. Without a sustainable path, the nature of the earth system can be altered to levels that cannot sustain life or change environmental conditions substantially. The Gaia hypothesis predicts a self-regulating behavior of biological systems [14]. The resilience of the earth system to a recovery becomes difficult when the system is beyond certain threshold levels [15].

Sustainable development, defined by Brundtland Commission, aims to meet the needs of the present without compromising the ability of future generations to meet their own needs [16]. This is often difficult and complex issue in practice given the intergenerational nature of the issue [17]. Decision approaches that are often used in dealing with sustainabilityare weak sustainability (allows substitutability of natural capital by economic capital) and strong sustainability (stricter rules of maintaining each capital type for system stability) [18]. Sustaining the earth system depend on achieving a balance in ecological, economic, and social dimensions [19] of sustainability.

There is a critical need for research and observations into science, policy, and governance of the earth system. Some areas relevant include multidisciplinary research are earth system dynamics, uncertainty, observational systems, system composition, climatic forcing, atmospheric sciences, geology, biogeochemistry, watershed science [20], climatic change, vulnerability [21], global hydrologic cycles, global governance [22], ecosystem services [23], spatial processes, temporal changes, forecasting, adaptation [24], mitigation [25], policy, and socio-economic systems.

The need for assessing tradeoffs between human and natural environment, adaptiveness of human-environmental systems [26], long term trends, theory and modeling of variation in interactions, sustainable transition, and evaluation of trajectories are identified as vital toward the science of sustainability [27]. Measurement and monitoring of societal transitions to sustainable future is important toward sustainability [28], including upgrading and maintenance of earth observation systems [3].

There is a need for a multi-scale and across scale assessment [29] of processes involved in the dynamics of the earth system. Such assessment need integration of multidisciplinary knowledge [30] and a systems approach to assessment and modeling of earth processes and trajectories. Research into specific areas of earth system response to climate change includes impacts on water resources, soil, air quality, biosphere, oceans, and human systems. The research also needs to be integrated into a multi-scale, systems framework that can be used to assess the system state and trajectories of the earth for sustainability assessment.

Earth system is composed of subsystems like marine and landscape systems that are complex adaptive systems that have inherent nonlinearities and have potential for sudden loss of robustness [31]. Stakeholder participation and citizen science efforts play an important role in policy and decision making for sustainability. Challenges in global sustainability include strengthening observation systems, innovation in responses, forecasting future conditions, appropriate responses, and confining disruptive change [2].

In summary, sustainability of earth system is critical to support and sustain life and human activities. There is a need for a multidisciplinary framework for earth sustainability that links science and policy to various spatial and temporal scales. While the task of sustaining earth system involves managing natural, social, and economic systems with considerations of limits, the role of thresholds, nonlinearities, resilience, and adaptiveness play a vital role. There is clearly a need for a systems based assessment and modeling that involves multi scale observations and response. The uncertainty in system-wide effects, population dynamics, and climatic change continue to be a major challenge in earth system research. There is a need for continuous, broad scale, and high resolution observation of biophysical and socioeconomic processes. Linking social and ecological systems as interacting and adaptive components of the earth system can develop new insights into governance and science observations that will be useful for developing sustainable solutions.