Population distribution significantly shapes a nation’s environmental conditions. In a country with a large population, where people reside, work, and consume resources exerts considerable pressure on natural systems. This geographical spread of human activity directly influences resource demand, pollution levels, and the overall ecological balance.
Characteristics of China’s Population Distribution
China’s population distribution presents a distinct pattern, largely defined by the “Hu Line,” also known as the Heihe-Tengchong Line. This diagonal line, drawn by geographer Hu Huanyong in 1935, stretches approximately 3,750 kilometers from Heihe in Heilongjiang Province to Tengchong in Yunnan Province, dividing the country into two demographic halves. To the east of this line, approximately 94% of China’s population inhabits just 43% of the land area, resulting in an average population density of around 314.85 people per square kilometer. This eastern half includes the densely populated coastal provinces and major river basins like the Yangtze and Yellow Rivers.
Conversely, the vast western portion, comprising 57% of the country’s land, is home to only about 6% of the population, with an average density of roughly 15.34 people per square kilometer. This sparsely populated western region is characterized by arid climates, extensive mountains, high plateaus, and deserts. The Hu Line also roughly corresponds to the 400 mm annual precipitation isotherm, separating the historically agricultural east from the more nomadic west.
This demographic imbalance has been further accentuated by rapid urbanization trends. China’s urbanization rate surged from 17.92% in 1978 to 64.72% by 2021, with projections indicating that over 50% of the population will reside in cities by 2030. The growth of megacities, particularly in the eastern regions, has led to a substantial increase in urban land area, expected to expand by almost 400% between 2000 and 2030, while the urban population grows by over 100%. This concentration of people and development creates unique environmental challenges.
Environmental Impacts of Distribution
China’s uneven population distribution creates significant environmental consequences. Resource depletion, particularly water scarcity, is a concern. The North China Plain, which contains two-thirds of China’s cropland and 43% of its population, possesses only 14% of the country’s water supply. This leads to per capita water availability of only 225 cubic meters per year. Consequently, there is an increasing reliance on groundwater aquifers, with levels in areas like Hebei Province dropping by an estimated three meters annually.
Pollution also impacts air, water, and soil quality. Air pollution, often manifesting as severe smog, is prevalent in highly populated urban centers. Cities such as Beijing and Shanghai frequently experience annual mean concentrations of respirable particulate matter (PM2.5) that approach or exceed 100 µg m−3, significantly higher than international guidelines. These pollutants originate from industrial activities, vehicle emissions, and the extensive burning of coal for heating and cooking, particularly in northern cities and rural areas. Such air quality issues contributed to an estimated 470,000 premature deaths in China in 2000.
Water pollution is widespread, with 60% of China’s cities facing water shortages and an estimated 500 million residents exposed to contaminated drinking water. Industrial discharge, domestic sewage, and agricultural runoff containing fertilizers and pesticides are major contributors. In 2012, China discharged 68.5 billion tonnes of wastewater, a volume comparable to the Yellow River’s annual flow, with domestic wastewater accounting for about 68% and increasing with urbanization. Analysis indicates that approximately 30% of surface water is of poor quality, and over 80% of groundwater is unsuitable for drinking.
Soil contamination also impacts food safety. Surveys indicate that 16.1% of soil samples, including 19.4% of agricultural soils, are contaminated with organic and chemical pollutants, as well as heavy metals like cadmium, lead, and arsenic. An area roughly the size of Taiwan is considered too polluted for farming. Heavy metals, largely from industrial activities and coal consumption, accumulate in crops, posing health risks to consumers.
Land degradation results from population distribution and human activities. Urban sprawl consumes arable land, with China losing over two million hectares of farmland to urbanization. This expansion increases demand for construction land. Deforestation, driven by unregulated logging and land conversion for plantations, has led to an annual decrease of 50,000 square kilometers of undisturbed primary forest. Desertification affects 27.4% of China’s land, impacting around 400 million people, largely due to overgrazing, poor water management, and inadequate irrigation in drier regions.
Biodiversity loss stems from habitat destruction and fragmentation. Rapid urban development and infrastructure projects, particularly in eastern coastal regions, have led to habitat loss, impacting diverse ecosystems and species. This has resulted in a decline in wildlife populations and ecosystem services. For example, 15% to 20% of higher plant species and 233 vertebrate species are endangered, and the giant panda population significantly declined from 46,000 in the 1950s to fewer than 1,000 in 2006. Furthermore, 90% of grasslands and 40% of wetlands have deteriorated.
Mitigation Efforts
China has implemented strategies and policies to address environmental impacts from its population distribution. The government has embraced “ecological civilization,” integrating environmental protection with economic and social development. National plans like the 14th Five-Year Plan and the “1+N” policy system aim for decarbonization and green development. China has committed to peaking carbon dioxide emissions before 2030 and achieving carbon neutrality before 2060.
Investments are being made in renewable energy and energy efficiency. The new renewable energy plan targets an increase in annual renewable energy consumption to one billion tons of standard coal equivalent by 2025 and 1.5 billion tons by 2030. These efforts include integrating renewable energy into urban planning, mandating green building standards for new constructions, and promoting solar panels and energy-efficient systems. Industrial energy efficiency has also improved, with energy consumption per unit of added value in key industrial sectors dropping by 5.6% in 2021.
Urban planning initiatives manage growth and reduce environmental footprints. Over 200 of China’s 600 major cities have announced low-carbon development goals. Specific measures include reducing construction land and population density in downtown areas, exemplified by Shanghai’s policy to “never widen” 64 roads in its old urban center. The “sponge city” concept is also implemented, featuring designed flood management systems and rainwater harvesting to supplement water supplies.
Reforestation and ecological restoration projects are extensive. China has undertaken large-scale programs like the Natural Forest Protection Program and the Grain-for-Green Program since the late 1990s, aimed at increasing forest cover and curbing soil erosion. These efforts have led to the restoration of over 6.7 million hectares of ecosystems, encompassing mountains, rivers, forests, farmlands, lakes, grasslands, and deserts. The Master Plan for Major National Projects to Protect and Restore Important Ecosystems (2021–2035) guides these efforts.
Measures to control industrial pollution and improve waste management are also pursued. The country has invested approximately RMB 2 trillion to address water pollution and enhance wastewater treatment infrastructure. Progress in air pollution control is evident, with harmful particulate matter concentrations in Chinese cities decreasing by 40% between 2013 and 2020.