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Global Change

Author: Prof Mary Scholes ~ University of the Witwatersrand Institute for the Study of the Environment (WiSE)

( Article Type: Explanation )

Global change refers to an interconnected set of phenomena, resulting largely from human actions that have altered the environment over virtually the entire planet at an accelerating rate during modern times. It includes changes to the composition of the atmosphere; the nutrient loading of the biosphere; the global, regional and local climate; the distribution and abundance of species; the cover and use of the land surface and the use of marine resources; the size, location and resource demands of the world’s human population, as well as its patterns of governance and economic activity.

Some facts about Global Change
After much debate, contemporary climate change has become accepted as a scientific reality, and the facts relating to global change have become central issues to be addressed by researchers, innovators, decision makers and governments around the world. The ways in which human societies engage with their environment to satisfy basic needs, stabilise and grow their economies and improve their quality of life, affect and are affected by the natural cycles that regulate the land, water and air
Changes are occurring so rapidly, however, that greater understanding of the Earth’s natural processes, the human influence on these processes and the interactions between the two has become a global priority – as has the need to find ways to mitigate these changes where possible, and to adapt to them.
Climate change is not new and during its existence the Earth has experienced significant variations, manifested in its ice ages, for instance, and periods of warming. Of particular concern today, however, is the unprecedented speed at which the planet is warming and the clear human-induced component. Human activity in the form of industrialisation and altered land use over the past 150 or so years has had byproducts that are altering the composition of the atmosphere. Carbon dioxide from the burning of fossil fuels such as coal, oil and gas have increased the amount of greenhouse gases to create what is known as an ‘enhanced greenhouse effect’, trapping additional heat energy within the atmosphere, which is predicted to have a range of effects on the planet’s climate.

South Africa’s unique advantage for understanding
regional influences on Global Change

Within its borders South Africa contains an economic spectrum ranging from capital-intensive industries to subsistence farming and from prosperity to extreme poverty, and hence is a living laboratory in which the reconciliation of these extremes is a critically important goal. Rapid population growth, rising expectations in the quality of life and full employment have to be accommodated and managed within the context of available resources without compromising future options.
Because of its location, South Africa’s climate is influenced by three oceans, the Indian, Atlantic and Southern oceans. The Agulhas Current along the Indian Ocean coast and the Benguela upwelling system on the Atlantic coast are critical for sustaining our marine resources. The oceans and the atmosphere are responsible for the climate experienced by the sub-continent and any perturbations in climate, such as greater drought frequency, increased temperature or more frequent floods will affect food security adversely. Climate change will not only pose greater risks to agriculture and fisheries but threatens our unique biodiversity and also may result in the increased incidence of human, animal and plant diseases.
Global models of climate change do not address adequately the prediction of rainfall, temperature and evaporation for our heterogeneous landscape with its steep rainfall gradients over tens of kilometres and ecotonal switches in rainfall seasonality. Hence, our ability to forecast the weather and climate at a seasonal scale useful to farmers, disaster prevention agencies, health services and other decision-makers requires a local perspective. Climate research and monitoring on the sub-Antarctic Islands and Antarctica provide further data for refining these models.

The interconnectivity of climate change and global change
Whilst climate change has the potential to affect our natural resources adversely, there are concomitant effects from other Global Change factors such as urbanization, resource harvesting, invasive species, pollution, atmospheric carbon dioxide (CO2) fertilisation and land use change. These interact with climate change to produce the phenomenon of Global Change. Ultimately we recognize the interconnectivity of global socio-economic and political drivers (as manifested in globalization), global climate change and impacts at the local level that influence the well-being of people both globally and in regions, nations and local communities. Life on Earth is possible because of the biogeochemical and physical cycles that regulate the atmosphere, water and nutrients on which people depend. These cycles are in turn influenced by human activity (see diagram below). The human and natural environments are indivisible when humanity’s continued existence and well-being on this planet is contemplated.
The Earth System functions as a result of interactions between the land, the oceans and the atmosphere. People depend on the services provided by these linked land-ocean-atmosphere sub-systems for their existence

Similarly the interconnectivity of the three major natural sub-systems constituting the world: the atmosphere, oceans and terrestrial systems has to be recognized. Each of these systems interacts with, and influences processes occurring in the other spheres. For millennia these interactions have tended towards creating an environment that allowed for the development and expansion of humankind. In the last few centuries, human activity has modified this environment to support exponentially growing human populations. However, in this display of human resourcefulness we are now exceeding the capacity of these sub-systems to moderate the impacts of resource use through feedback loops. The networks of regulatory processes which operate between the oceans, the atmosphere and land have reached critical limits and are failing to support the environment on which we depend. Human initiative, ingenuity and creativity are required to address these issues urgently.

Drivers and shapers of global change
‘Global Change’ is a syndrome consisting of linked changes in the biogeochemistry of the Earth, the distribution, size, consumption patterns and use of technology by human populations, the land cover and state of the oceans, the abundance and diversity of other species, and the mean state and variability of the global climate. The syndrome has come to dominate the functioning of the biosphere, especially over the past century. Global Change can be thought of as a disruption or stress applied to the Earth System (where that system explicitly includes human subsystems). It is not possible to understand these changes in isolation, nor to plot a path to a sustainable future without understanding their interconnections and feedback pathways. The world has changed more, in many vital respects, over the past two centuries (and especially the past 50 years) than at any other time in the history. As a consequence of the rapidly growing human population, but more particularly as a consequence technological innovation, humans are appropriating an increasing share of the Earth’s resources, transforming larger parts of its surface, dominating the cycles of its essential elements, altering the global climate, and driving other species to extinction. At the same time, the people of the world are increasingly urbanised, engaged in long-distance trade, and organised in highlyconnected systems of government. All these changes are not independent: they form a linked syndrome that is collectively known as ‘Global Change’. Together they arguably constitute the greatest challenge that humankind collectively has had to face during its entire existence and are a perturbation to the Earth System of comparable magnitude to the last major asteroid impact, that is believed to have led to the extinction of the dinosaurs ~65 million years ago. The complex of environmental and social changes must be addressed in an integrated, globally coordinated way, if solutions necessary for the continuation of complex human societal development are to be effective.
The core processes that underlie the changes in the global environment have been clearly identified (see diagram below) and have been unequivocally linked to human activity. There remains much uncertainty about their coupled dynamics over the next century and beyond, specifically relating to the strengths of various feedback loops that may serve either to slow the rate and extent of change, or accelerate and amplify it. It is understood at a theoretical level that a complex system of non-linear interacting factors incorporating time-lags and spatial heterogeneity is unlikely to change in a smooth and predictable fashion when nudged in a particular direction.
The Earth System has in the past been characterised by sudden changes, which often become effectively irreversible. It is not known where the thresholds for such changes in the future may lie, since the global environment at the beginning of the 21st century is in many respects unprecedented. Improving scientific understanding of global change: The 10-Year Global Change Research Plan
South Africa’s Department of Science and Technology (DST) released its Ten-Year Innovation Plan for South Africa, Innovation Towards a Knowledge-based Economy 2008- 2018. This landmark publication identifies five broad areas on which efforts within the National System of Innovation are to be concentrated. The scale of the proposed key knowledge and innovation priorities is very ambitious, and they have thus been described as grand challenges. One of the grand challenges is the science and technology for global change, with a focus on climate change, commonly known as the Global Change Grand Challenge. The Global Change Grand Challenge supports knowledge generation and technological innovation to enable South Africa, Africa and the world to respond to global environmental change, in an informed and innovative way.


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