Modeling and Evaluating the Global Energy Flow in Ecosystems and its Impacts on the Ecological Footprint

Abstract Energy is the source of the cycling in the global Earth ecosystems. Without it, the Earth will not be able to function to provide goods and services. While matter can be recycled in ecosystems essentially endlessly, energy can be used only once for each new cycle. In the Earth’s ecosystems, the two fundamental laws are the cycling of matter and the one-way flow of energy. Because the global ecological footprint and the demand for energy are rising, the impact of energy availability is of crucial importance and energy needs across the globe are not assured. What are the impacts of a continuously escalating demand for energy on the global ecosystem? The global ecosystem is the part of the Earth that assures the maintenance of production of natural resources that provide survivability of the global biological and human social systems. The modeling of energy in the global ecosystem will provide the scientific analysis that might be of interest to the global use of energy. In this respect, the energy enters an ecosystem through green plants (the producers) converting low-energy carbon dioxide into high-energy carbohydrate, then passes through one or more of the organisms (consumers and decomposers) of the community, and is then lost to the ecosystem into outer space and never returns; each new day needs the Sun to shine. Eventually, all the energy that enters the ecosystem is lost in the form of dissipated heat. Almost every aspect of life, and particularly human food production, is facing shortages. The Global Energy Model (GEM) in its theoretical approach has been developed using different time series of published data that are available on the websites of Earth-Trends of the World Research Institute (WRI), World Bank, Food and Agricultural Organization (FAO), United Nation Development Program, World Wildlife Fund (WWF), and Global Footprint Network. The data were incorporated into STELLA Modeling Tool using the fourth-order Runge–Kutta integration method. Further, the model incorporated the estimated density of power (in watts per square meter) received from the Sun from which we could calculate the energy reservoir on the Earth globally. The model provides the energy balance in the global ecosystems in light of the increase of human population. Accordingly, the human population is expected to reach 9.3 billion people by 2050 on the Earth and might reach between 11.0, 18.1, and 20.1 billion people in the year 2100 based on the very conservative estimates, the current trends of the estimates, and also the upper estimates. Additionally, the current needs of the human footprint for goods and services, including the energy from the Earth, are three to five times the current Earth size. The impacts of increasing human population will occur all along the energy chain from exploration, to production, distribution, and use. Ecosystems that are negatively affected by shifts in energy systems, for example, toward more intensive cropping for biofuels, may not be able to provide the range of goods and services, which they currently provide or potentially could provide. Changes in ecosystem services will affect the provisioning of goods and services further, impacting people, particularly those who rely directly on nature for their livelihoods. Further, climatic changes may have other impacts on establishing the links between ecosystem services, energy provision, human population by looking at the current status of ecosystems that directly provide energy services, anticipated demand for energy (production, distribution, consumption) and the key elements that impact the management of ecosystem services and related energy systems, as well as how climate-change impacts may change or shift energy demand and adaptation measures to be adopted globally.