Our planet is not an inexhaustible treasure trove; it's like a spaceship in the universe with clearly defined carrying capacity limits.
As early as the 1920s, ecologists clearly defined environmental carrying capacity as "the limit value of the number of biological populations and individuals under specific environmental conditions" 1 . As human understanding of Earth's finite resources deepened, this concept gradually expanded from ecology to the entire field of resources and environment.
In 1972, the "Club of Rome" published "The Limits to Growth," which systematically defined the concept of resource and environmental carrying capacity for the first time, warning of the potential global growth limits caused by rapid industrialization, population explosion, depletion of non-renewable resources, and ecological degradation 1 .
Humanity's intuitive understanding of finite resources and environment dates back to ancient times, but true theoretical exploration began in the 19th century. In 1838, Belgian mathematician Pierre François Verhulst first proposed a mathematical equation describing population growth constrained by the environment, laying the mathematical foundation for the carrying capacity concept 2 .
Verhulst introduces the logistic equation, providing mathematical foundation for carrying capacity 2 .
First documented use of "carrying capacity" term in U.S. Senate report 2 .
Term becomes common in biological sciences 2 .
Eugene P. Odum defines carrying capacity as equilibrium value in logistic population model 2 .
"The Limits to Growth" published, bringing concept to global attention 1 .
In population ecology, environmental carrying capacity is defined as the population equilibrium point when the number of births equals the number of deaths 2 . This concept can be precisely described by the logistic growth model:
Where N is the population size, r is the intrinsic growth rate, K is the local environmental carrying capacity, and dN/dt represents the rate of change in population size over time 2 . This model exhibits a typical S-shaped growth curve—when the population size is well below the carrying capacity, growth is approximately exponential; when approaching the carrying capacity K, growth gradually slows, eventually stabilizing at K 2 .
Regions influence each other through resource flows and environmental impacts.
Carrying capacity changes with technological and economic conditions.
Different regional levels have different carrying capacity limits.
As carrying capacity research deepened, scholars developed various evaluation methods, each with different emphases to suit different scenario needs.
Assesses regional sustainable development by calculating the supply-demand relationship of natural resources from human economic activities 1 .
Explains causality from internal system structure through dynamic models, widely used for future early warning in carrying capacity research 1 .
Aims to convert different types of energy into a comprehensive emergy index system with unified standards 1 .
Chinese Academy of Sciences team built a comprehensive evaluation system based on these principles, classifying carrying capacity into three types 1 .
In 2019, a Beijing resource and environmental carrying capacity study based on the PS-DR-DP theoretical model provided an innovative example of metropolitan carrying capacity assessment 1 .
The study constructed a theoretical model of three pairs of interacting forces: "Pressure—Support Force," "Destructive Force—Restorative Force," and "Degradation Force—Enhancement Force" 1 . These forces correspond to resource support capacity, environmental capacity, and risk disaster resistance capacity respectively 1 .
| Year | Carrying Capacity State Value | Population Size (10k) | Carrying Contribution Mean | Carrying Grade |
|---|---|---|---|---|
| 2010 | 1.0143 | 1962 | 0.642 | Grade II (Unstable State) |
| 2015 | 1.1411 | 2171 | 0.7025 | Grade III (Ideal Carrying) |
Contrary to common belief, despite Beijing's continuous population growth, resource pressure slightly decreased 1 .
In 2015, Beijing's population reached 21.71 million, with a carrying contribution mean of 0.7025, entering the optimal carrying threshold with further carrying capacity space 1 .
The study showed that Beijing's resource and environmental carrying capacity tended toward an ideal carrying state between 2010-2015 1 . Compared to 2010, the negative factor effect weakened in 2015, while the positive factor comprehensive effect strengthened 1 . This finding provided theoretical support for controlling Beijing's population size within 23 million by 2020 1 .
To scientifically evaluate resource and environmental carrying capacity, researchers need a series of professional tools and methods:
| Tool Type | Representative Method | Main Function | Application Scenario |
|---|---|---|---|
| Mathematical Models | Logistic Model | Describes relationship between population growth and resource constraints | Ecology, Population Studies |
| Comprehensive Evaluation | State Space Method | Multi-indicator comprehensive assessment | Regional Carrying Capacity Evaluation |
| System Analysis | System Dynamics Method | Simulates long-term dynamic behavior of complex systems | Carrying Capacity Early Warning Prediction |
| Spatial Technology | GIS Spatial Analysis | Visualizes spatial differences | Territorial Spatial Planning |
| Indicator Integration | Ecological Footprint Method | Measures human demand on ecosystems | Sustainable Development Assessment |
| Early Warning Systems | Monitoring and Warning Platform | Real-time monitoring of carrying capacity changes | Resource and Environmental Management Decisions |
Resource and environmental carrying capacity research has evolved from pure theoretical exploration to an important tool supporting sustainable development. In China, it has become a core basis for territorial spatial planning, disaster recovery and reconstruction (such as post-Wenchuan earthquake reconstruction), and regional development strategy formulation 1 3 .
The Millennium Ecosystem Assessment, Ecological Footprint Accounts, and Planetary Boundaries research have all documented evidence that humanity has exceeded Earth's carrying capacity 2 .
In 2012, 22 researchers expressed concern in Nature that the biosphere might be "approaching a state shift" 2 .
Looking ahead, resource and environmental carrying capacity research is moving toward multidisciplinary integration, dynamic monitoring and early warning, and refined assessment. With advances in big data, artificial intelligence, and remote sensing technology, we will be able to more accurately assess Earth's health and provide scientific navigation for sustainable development.
Just as a spaceship must understand its carrying limits to voyage far, humanity must wisely plan its development path while recognizing Earth's boundaries. Resource and environmental carrying capacity research is our scientific attempt to explore the path of harmonious coexistence with Earth, guiding us toward a more resilient future.