Earth system science

See also: Earth science and Gaia hypothesis

Earth system science seeks to integrate various fields of academic study to understand the Earth as a system. It looks at interaction between the atmosphere, hydrosphere, lithosphere and biosphere.

In 1996, the American Geophysical Union, in cooperation with the Keck Geology Consortium and with support from five divisions within the National Science Foundation, convened a workshop "to define common educational goals among all disciplines in the Earth sciences." In its report, participants noted that, "The fields that make up the Earth and space sciences are currently undergoing a major advancement that promotes understanding the Earth as a number of interrelated systems." Recognizing the rise of this systems approach, the workshop report recommended that an Earth system science curriculum be developed with support from the National Science Foundation.

Definition

The Science Education Resource Center (SERC), an office of Carleton College, offers the following definition: "Earth system science embraces chemistry, physics, biology, mathematics and applied sciences in transcending disciplinary boundaries to treat the Earth as an integrated system and seeks a deeper understanding of the physical, chemical, biological and human interactions that determine the past, current and future states of the Earth. Earth system science provides a physical basis for understanding the world in which we live and upon which humankind seeks to achieve sustainability."

Inspiration in the Gaia theory

After much scientific criticism, many elements of the Gaia theory are now considered within ecological science, basically consistent with the planet Earth being the ultimate object of ecological study. Ecologists generally consider the biosphere as an ecosystem and the Gaia theory, though a simplification of that original proposed, to be consistent with a modern vision of global ecology, relaying the concepts of biosphere and biodiversity. To promote research and discussion in these fields an organisation, "Gaia Society for Research and Education in Earth System Science" was started.

An example of the change in acceptability of Gaia theories is the Amsterdam declaration of the scientific communities of four international global change research programmes — the International Geosphere-Biosphere Programme (IGBP), the International Human Dimensions Programme on Global Environmental Change (IHDP), the World Climate Research Programme (WCRP) and the international biodiversity programme DIVERSITAS — recognise that, in addition to the threat of significant climate change, there is growing concern over the ever-increasing human modification of other aspects of the global environment and the consequent implications for human well-being.

The programmes have stated the following:

Research carried out over the past decade under the auspices of the four programmes to address these concerns has shown that:

1. The Earth System behaves as a single, self-regulating system with physical, chemical, biological, and human components. The interactions and feedbacks between the component parts are complex and exhibit multi-scale temporal and spatial variability. The understanding of the natural dynamics of the Earth System has advanced greatly in recent years and provides a sound basis for evaluating the effects and consequences of human-driven change.
2. Human activities are significantly influencing Earth's environment in many ways in addition to greenhouse gas emissions and climate change. Anthropogenic changes to Earth's land surface, oceans, coasts and atmosphere and to biological diversity, the water cycle and biogeochemical cycles are clearly identifiable beyond natural variability. They are equal to some of the great forces of nature in their extent and impact. Many are accelerating. Global change is real and is happening now.
3. Global change cannot be understood in terms of a simple cause-effect paradigm. Human-driven changes cause multiple effects that cascade through the Earth System in complex ways. These effects interact with each other and with local- and regional-scale changes in multidimensional patterns that are difficult to understand and even more difficult to predict.
4. Earth System dynamics are characterised by critical thresholds and abrupt changes. Human activities could inadvertently trigger such changes with severe consequences for Earth's environment and inhabitants. The Earth System has operated in different states over the last half million years, with abrupt transitions (a decade or less) sometimes occurring between them. Human activities have the potential to switch the Earth System to alternative modes of operation that may prove irreversible and less hospitable to humans and other life. The probability of a human-driven abrupt change in Earth's environment has yet to be quantified but is not negligible.
5. In terms of some key environmental parameters, the Earth System has moved well outside the range of the natural variability exhibited over the last half million years at least. The nature of changes now occurring simultaneously in the Earth System, their magnitudes and rates of change are unprecedented. The Earth is currently operating in a no-analogue state.

Sir Crispin Tickell in the 46th Annual Bennett Lecture for the 50th Anniversary of Geology at the University of Leicester in his recent talk "Earth Systems Science: Are We Pushing Gaia Too Hard?" stated "as a theory, Gaia is now winning."

He continued "The same goes for the earth systems science, which is now the concern of the Geological Society of London (with which the Gaia Society recently merged). Whatever the label, earth systems science, or Gaia, has now become a major subject of inquiry and research, and no longer has to justify itself."

These findings would seem to be fully in accord with the Gaia theory. Despite this endorsement, the late W. D. Hamilton, one of the founders of modern Darwinism, whilst conceding the empirical basis of the planetary homeostatic processes on which Gaia is based, states that it is a theory still awaiting its Copernicus. The homeostatic nature of the global system has been recognized as a consequence of the 2^nd law of thermodynamics. In their comprehensive book on the thermodynamics of life, Eric D. Schneider and Dorion Sagan argue that Gaia belongs to a class of complex thermodynamic systems, not just living ones, that are naturally purposeful; and that life optimizes rather than maximizes entropy production.

Scientific Journal

Studies related to the discipline are published in the Journal of Earth System Science, formerly titled Proceedings of the Indian Academy of Sciences (Earth and Planetary Sciences).