Balanced and imbalanced: global population spatial mobility and economic patterns in coastal and interior areas

The evolution of regional space between coastal and interior areas directly manifests the theory of regional economic development imbalance. Prior research has underemphasized the impacts of population and economic factor flows on development balance between coastal and interior regions. By constructing a global coastal–interior population–economy panel dataset and a threshold effect model, this study examines regional development imbalance at the largest scale between global coastal ("near regions" within 100 km of the sea) and interior ("far regions" beyond 100 km) areas for 2000–2018. Results show global population is unevenly distributed: coastal areas (18.43% of land) host 52.8% of the global population, and about 23% of the global population is concentrated in coastal subtropical zones (10°–30° N/S). The coastal–interior economic pattern has become more balanced: the per capita GDP gap declined from 2.08× to 1.78×. However, population factor evolution lags economic factor evolution. Except for Africa, intercontinental coastal–interior development gaps converge to varying degrees. Adjusting regional per capita income levels and population–economic density promotes balanced development between coastal and interior areas globally and across continents. These findings inform policies for spatial balance and sustainable development at multiple scales, extend theory on uneven regional growth, and support progress toward the UN 2030 Agenda.

Xiaoming Jin, Weixin Luan, Jun Yang, Chuang Tian