Ecological Footprint and ecological carrying capacity

Ecological Footprint and ecological carrying capacity

The concept of ecological carrying capacity has evolved from the Population Carrying Capacity of the natural ecosystem to the resource carrying capacity and environmental carrying capacity. His concepts are constantly evolving. The carrying capacity of the urban ecosystem can be defined as follows: under normal circumstances, the urban ecosystem maintains its own potential for healthy and stable development, the main manifestation is the ability of the urban ecosystem to defend against the stress that may affect or even damage its health status, the ability to recover after the stress disappears, and the ability to develop to achieve a certain target.

This definition is very abstract. In actual work, it is often quantified using the external representation of the carrying capacity of population and other urban ecosystems. Currently, domestic and foreign scholars generally use the ecological bearing capacity quantification method, that is, to characterize the carrying capacity of the urban ecological system by the units of available land area. Ecological Footprint is a method proposed in the early 1990s s to measure the degree of sustainable development from an ecological perspective. The ecological footprint measures the amount of natural resources consumed by humans to continue their development under certain conditions of population and economic scale, and summarizes the impact of human activities on the biosphere into a number, that is, the biological production land exclusively occupied by human activities. The ecological footprint of a known population (individual, city, or country, that is, the area of biological production (including land and water) required to produce all the resources consumed by the corresponding population and to consume all the waste produced by the population ). Comparing the ecological footprint with the biological production area provided by the country or region can determine whether the production and consumption activities of a country or region are within the carrying capacity of the local ecosystem. Simply put, the ecological footprint is the need of the ecosystem, and the ecological carrying capacity is the supply of the ecosystem. The two can calculate the ecological deficit or ecological surplus. This is the application of the ecological footprint method in the study of ecological carrying capacity. The Ecological Footprint Method is mostly used in the evaluation of the current situation of the urban ecosystem. It analyzes the utilization of natural resources by the population in the region and the sustainability of the region at the computing moment.

The measurement of sustainability in the ecological footprint is a "strong" Measurement Method of sustainability. When the ecological carrying capacity of a region is smaller than the ecological footprint, an "ecological deficit" occurs. When the ecological carrying capacity exceeds the ecological footprint, an "ecological surplus" occurs ". The ecological deficit indicates that the human load in the region exceeds its ecological capacity. To meet the current consumption needs, the region must either import resources lacking outside the region to balance the ecological footprint, either by consuming its own natural capital to make up for the lack of income and traffic.

Based on the difference in productivity, ecological footprint analysis divides the bio-productive land on the earth's surface into six categories for accounting: 1) fossil energy land, the land to be reserved to compensate for the loss of natural capital due to fossil energy consumption; 2) the most productive land in arable land and bio-productive land; 3) Grassland, (4) land suitable for the development of animal husbandry; (4) Forest Land refers to artificial forests or natural forests that can produce wood products; (5) land for construction, including land occupied by various types of living facilities and roads; (6) waters, including freshwater waters and oceans that can provide biological production.

The ecological footprint is calculated as follows:

1) Calculate the per capita ecological footprint of various consumption Projects

The calculation formula for a I is as follows:

A I = Ci/YI = (PI + II-EI)/(yi × n)

Formula: I is the type of the consumption project, AI is the per capita ecological footprint (hm2/person) converted from the I consumption project, and Ci is the per capita consumption of the I consumption project, yi is the world's average annual output (kg/hm2 ), pi, II, and ei are respectively the annual production volume, annual import volume, and annual export volume of the I-th consumption project. n is the population.

2) computing per capita ecological footprint

The formula for calculating the per capita ecological footprint e f is

EF = Σ Ei = Σ rja I = Σ RJ (P I + I-EI)/(Y I × n ),

Formula: EF is the average Ecological Footprint (hm2/person), EI is the average ecological footprint, and RJ is the equilibrium factor.

3) computing the ecological carrying capacity

The differences between the average output of a type of biological production area in different countries or regions and that of the world can be expressed by the "yield factor. The yield factor of a type of land is the ratio of its average productivity to the average productivity of similar land in the world. Multiply the existing land types by the corresponding equilibrium factor and local yield factor to obtain the ecological carrying capacity of a country or region (see figure 6 ).

The formula for calculating the per capita ecological carrying capacity is

EC = Sigma Cj = Sigma AJ × RJ × YJ,

Formula: EC indicates the per capita ecological bearing capacity (hm2/person), CJ indicates the per capita ecological bearing capacity, AJ indicates the per capita biological production area, RJ indicates the equilibrium factor, and YJ indicates the yield factor.

The ecological footprint varies with the total population, per capita consumption, and the resource density used by technologies. Technology can change the productivity level of the land, or the efficiency of resources used to generate goods and services. The ecological carrying capacity is affected by the productive land area and unit land production capacity. Changes in technology, population, and consumption will reduce or increase the gap between the ecological carrying capacity and the ecological footprint.

The Ecological Footprint describes the amount of resources occupied by humans from the perspective of consumption, while the environmental carrying capacity theory examines the number of people that the environmental system can afford from the perspective of supply. The most prominent advantage of the ecological footprint model is its Concise Expression and easy to understand. Compared with the traditional sustainable development evaluation method, it directly establishes the quantitative relationship between consumption and resources, and can effectively evaluate the impact of human activities on the environment. In the study of urban ecological planning, ecological footprint theory and method can be used in the following aspects: Analysis and Evaluation of the sustainable development level of urban ecology, to achieve sustainable urban development requires bio-productive area, the changing trend of the urban ecological footprint, the comparison of the ecological footprint between different cities, the adjustment of the industrial structure and consumption structure, and the change of the Resource Development and Utilization Model.