**1. Introduction**

It has been widely recognized that education has a significant positive effect on economic growth. Theodore W. Schultz argued in the human capital theory that education can help accumulate people's human capital so as to enhance their productivity in labor market [1]; this has been confirmed by empirical research in different countries and regions [2,3]. Higher education, in this way, plays an even more prominent role in economic development. Not only does it cultivate high-quality labor to increase the productivity of the whole society, but it also promotes technological and institutional innovation in order to improve the efficiency in production. Moreover, it should also be noted that higher education benefits people with knowledge and skills, and also changes their daily behaviors, or even shapes people's views and values in every way. All these possible effects of higher education on people will ultimately exert some impact on economic development, since the labor force is one of the basic factors in production [4]. Therefore, it is quite necessary to comprehensively explore the role of higher education in economic growth from different perspectives.

Previous research on higher education and economic development mostly employed traditional GDP as the measure of economic growth; however, this practice has long been critiqued, with the concern that GDP cannot accurately reflect the welfare of a nation. Even Richard Stone, one of the creators of the original GDP indicator, suggested that "the three pillars on which an analysis of society ought to rest are studies of economics, socio-demographic and environmental phenomena" [5]. The concept of green GDP emerged in this context, aiming to make up for the shortcomings of traditional GDP accounting. In contrast with the limitations of traditional GDP, green GDP essentially stands for the net positive effect of national economic growth. Nevertheless, there were many difficulties in calculating green GDP in empirical studies. Intuitively, we can get green GDP by deducting the costs of environmental consumption and pollution from the traditional GDP, but this is mainly theoretically feasible considering the complexity in calculating environmental pollution and the unavailability of data about resource consumption. Given these research gaps, is it possible to propose a new approach to indirectly estimate green GDP? How does higher education affect green economic development? Is there any difference of the role higher education plays in green GDP and in the traditional GDP? Our paper contributes by answering these three research questions. The contribution and limitations of prior literature in this field need to be reviewed and analyzed before we continue our research.

#### **2. Literature Review**

This section mainly consists of three parts: First, it brings in the typical Solow–Swan growth model as well as its modified versions that are commonly used considering economic growth, which will also prepare our analysis later in the research design section; second, it presents a review of previous studies about the impact of higher education upon economic development, based on which the third part identifies and elaborates the research gaps, i.e., the limitations of traditional GDP measure and the difficulties in calculating green GDP in empirical research.
