The Effects of Urbanization on Urban Land Green Use Efficiency of Yangtze River Delta Urban Agglomeration: Mechanism from the Technological Innovation

Although the focus of studies on ULGUE has now shifted from theoretical interpretation to empirical analysis, it is still necessary to investigate its nuances. ULGUE originated from green development [12], which coincides with the concept of sustainable development and green use proposed by the Chinese government. Existing research suggests that the core of urban land green use consists of emphasizing the region’s access to higher economic and social development while promoting conservation and use intensification [19], reducing energy loss [20], conserving land and resources and reducing negative environmental impacts [21], and producing less pollutant emissions [22]. ULGUE has been widely used to analyze the relationship between government planning, industrial agglomeration, urbanization strategies, land-use patterns, and spatial effects. ULGUE includes resources consumed through green or non-eco-friendly pathways as well as desired and undesired urban land-use outputs [23]. While requiring beneficial economic and social outputs, ULGUE focuses on the green benefits of land-use outputs, i.e., environmental protection during land use.

Human economic and social activities affect land use, e.g., production, recreation, and consumption, and are direct determinants of land-use patterns [22]. The impact of urbanization on land use has been discussed and consists of the following three main aspects.

First, from the perspective of socio-economic activities, urbanization drives economic and social development while inevitably having a negative impact on ULGUE. Spatial economic activities driven by urbanization are the key factor in the rapid changes in land use [24]. Urbanization puts great pressure on land use and the protection of environmental resources such as water [25] and air quality [26]. The challenge facing land use is to address the relationship between meeting human needs and maintaining the long-term capacity of the biosphere to provide goods and services [27]. Large areas of green land, including parks, green buffers, square spaces, and attached green space, are being transformed into urban and industrial areas to cater to economic growth, housing, and production [28], which decreases green outputs and creates significant undesired outputs. The spatial interaction between economies that is brought about by urbanization has benefited from the development of transport infrastructure. However, urbanization increases the number of vehicle kilometers travelled [29], which leads to increased negative externalities, including air pollution [30].

Second, from the perspective of population migration, urban population growth increases the inputs as well as the desired and undesired outputs of ULGUE. On the one hand, urbanization brings a large labor force, which together with industrialization, urbanization, and economic reform measures affects ULGUE as a factor of production [31]. The demand for various types of products and services generated by urban population agglomeration due to survival and development needs is transformed into a demand for different types of land within the urban area. This triggers the rapid accumulation of demands for land resource utilization. On the other hand, population migration from the urban fringes to cities leads to the abandonment of cultivated land in the area, which poses a greater threat to food security. A large influx of people into urban areas creates challenges for the urban living and productive land use, which negatively impacts the environment and increases undesired outputs. More seriously, in large cities, large public facilities for supplying energy and handling waste are often crowded out by residential areas, which include a wide variety of facilities, such as power plants, industrial parks, highways, and waste incinerators, which are identified as NIMBY (not in my back yard) facilities or LULU (locally unwanted land use) facilities; LULU facilities involve secondary air, water, soil, and noise pollution, which have a negative impact on the regional ULGUE.

Third, different modes of urbanization affect ULGUE in different ways. Urban sprawl leads to negative externalities such as high energy consumption [32], which reduces land-use efficiency [33,34]. Since the end of the 20th century, increasing land intensification activities have become an important factor affecting sustainable global growth. The process of urbanization in China is generally accompanied by a lack of development awareness of resource saving [35], which has resulted in the expansion of built-up areas and transport infrastructure areas and the reduction in the marginal efficiency of land use. Urban compactness is a response to control urban sprawl, but it also leads to urban problems such as traffic congestion, increased cost of living [5], and the undesired outputs of ULGUE. It has been shown that the ecological efficacy of urbanization in terms of pollution reduction and resource intensification can be better exploited through regulation and intervention by government departments [36]. As present, over-exploitation and the uncontrolled utilization of land resources in China have posed great challenges to regional sustainable development.

Existing studies have found that technological innovations can amplify the positive effects of urbanization on land use, the mechanisms of which have been tentatively elucidated. Classical IPAT theory identifies population size, affluence, and technology as key forces shaping land use, especially technological innovation, which can trigger rapid land-use change [37]. There is a tendency for urban centers to gather and form urban clusters [38]. Influenced by the learning, matching, and sharing mechanism of the agglomeration economy [39], urbanization is conducive to exchange among technicians, which helps the spilling over, diffusion, and incubation of knowledge and technology and prompts the continuous improvement of regional technological innovation in the virtuous circle of “innovation–spillover, diffusion-re–innovation”. The agglomeration economy brings technological innovation and externalities, and in turn, technological innovation promotes economic transformation, further amplifying the role of the population as a factor of production to promote economic growth and thus enhancing ULGUE. The inflow of different types of talents and emerging technologies improve the existing industrial structure, and the technologies have a positive effect on urban land use [40] and help to reduce environmental degradation [41], while technological externalities affect land intensification [42].

However, not all types of technological innovation have a facilitating effect; some have the potential to reduce ULGUE. It has been pointed out that technological innovation has a “rebound effect” [16]; i.e., technological innovation reduces the cost of production, which lowers the price of and expands the demand for products, leading producers to generate large quantities of products, which ultimately increases both energy consumption and carbon emissions. It has been pointed out that technological innovation increases pollution when the economic level is low [43]. Therefore, technological innovation has a facilitating or inhibiting effect on the efficiency of the green economy, and the ultimate impact of technological innovation on ULGUE is uncertain; its performance depends on the allocation of the elements of science and technology innovation and the specific type of innovation [44]. Therefore, specific types of technological innovations need to be further discussed. Combining existing studies on the impact of urbanization on ULGUE and urban land-use practices in China, this study argues that green, digital, and transportation technological innovations strengthen the contribution of urbanization to ULGUE.

First, advances in green technologies increase the efficiency of land use. Green technological innovation includes both energy-saving technological innovation and technological progress in emission reduction [45]. Energy-saving technological innovation is able to reduce energy loss in production, improve urban economic efficiency [46], and reduce the cost of reducing pollution [47]. Emission reduction technology can improve clean energy and reduce pollution emissions in production, which is a key approach to alleviate the pressure on the living condition, production, and environment brought about by population urbanization and to solve the contradiction between production and pollution [48].

Secondly, digital technological innovation is thought to provide agglomeration power, sustainable food production, access to clean and safe drinking water, and green energy production and use [49]. Increasing the proportion of non-fossil energy use and optimizing industrial structures are the two mechanisms by which digital technological innovation contributes to green use [50]. More importantly, digital technological innovation has produced subversive changes in geography, boundaries, space, and time [51], which breaks down administrative boundaries, shortens spatial distances, and promotes the integration of peripheral areas into the inner-core region [5], thus enhancing the overall efficiency of urban land use.

Thirdly, the interaction between land use, transportation, and the environment has been well researched [52]. Longer travelling distances due to urban sprawl as well as urban congestion prolongs vehicle driving and idling times, leading to air pollution from inadequate fuel combustion [53]. Traffic noise and the occupation of vehicle infrastructures such as car parks and roads are detrimental to sustainable and green urban development. Technological innovations in transportation reduce urban carbon emissions through improved accessibility and energy efficiency [54]. The electrification of transportation will improve air quality in the streets [55] and alleviate the congestion pressure on the roads, achieving both economic and environmental benefits [56] and thus reducing the negative impacts of urbanization on the environment [57]. Further, transportation technological innovation has a positive impact on land-use efficiency in opening up new urban spaces for efficient use, changing the urban pattern, reallocating resources, and reducing the need for new urban land by maintaining the marginal benefits of land use while urbanizing [58].