One of the most critical development problems in China is the existence of a considerable number of contiguous destitute areas (also known as regional poverty), and the causes behind such regional poverty might structurally differ by geographical characteristics. To deal with the problem, this paper, based on the “Three Nature” theory of New Economic Geography, first establishes an analytical index system of poverty causes, and then uses the gray relational method to identify the causes of poverty in 14 contiguous destitute areas. The results show that, at present, the main poverty causes in the mountain areas in eastern part of China, such as the Dabie mountain area, the Yanshan-Taihang mountain area and the southern Greater Khingan mountain area, are the shortage of human capital and information technology. In contrast, the main factors behind regional poverty in the central mountain areas such as the LuoXiao mountain area, the Lvliang mountain area and the Wuling mountain area are poor transport, locational and other natural factors. The western mountain regions such as Tibet, Tibetan areas in four provinces, South Xinjiang’s three districts and the West Yunnan border area are especially affected by natural endowments, but each area’s specific cause for poverty is different from one another. Finally, this paper discusses relevant policy issues regarding the fact that poverty causes are different by distinct natural factors.

Climate policy plays an important role in keeping global temperature rises below the target of 1.5–2 °C above pre-industrial levels, and technological innovations are key to determining the effectiveness of climate policy. In this study, we investigated the climate impact of the USA’s policy choices using the enforced multi-factor regional climate and economy system (EMRICES,) and the Earth system model from Beijing Normal University (BNU-ESM). Three emission scenarios were designed based on the assumption of whether or not the US follows its proposed nationally determined contribution (NDC) and makes use of technological innovations. The results showed that if the US does not implement the NDC and had no technological progress, there would be an extra 176.7 Gt of cumulative carbon emissions by the end of the 21st century compared to that of all the countries that follow their NDC. The additional emissions would lead to an increase of 62 ppm in CO₂ concentration and a 0.4 °C increase in global warming by 2100. It would also lead to a 2% loss for the US and Chinese economies, compared to the NDC scenario. The Earth system model results also show that even if all the countries follow the DNC, it would be difficult to keep the temperature from increasing less than 1.5 °C. This study implies that the US withdrawal from the Paris Agreement and their refusal to adopt technological progress is not conducive to achieving the 1.5 °C goal, and more stringent emission reduction targets or technology innovations would be required for the world to control global warming to a level below 1.5 °C.