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The urbanization impacts on surface air temperature (SAT) change in the Guangdong‐Hong Kong‐Macau region (GHMR) from 1979 to 2018 are examined using homogeneous surface observations, reanalysis, and remote sensing. Results show that the warming due to urbanization tends to be smaller or insignificant as the spatial scale increases. The urbanization contribution to the local warming can reach as high as 50% in the center of each metropolis, remains high (~25%) in the Greater Bay Area (GBA), and decreases to about 10% in the whole GHMR. The warming in GHMR is nearly uniform throughout the day, and therefore, the observed trend of the diurnal temperature range (DTR) is not statistically significant. However, the urbanization contribution exhibits distinct seasonal variations, large in summer and autumn while smaller in winter and spring. Plain Language Summary: The Guangdong‐Hong Kong‐Macau region (GHMR), especially the Greater Bay Area (GBA), is a region typical of China's economic development and rapid urbanization. To precisely assess how much the urbanization contributes to the regional warming, we comprehensively evaluate the urbanization warming and its uncertainties in GHMR by using more careful processed and assessed data (observations, reanalysis, and remote sensing) and different analysis methods. The results show that the warming due to urbanization tends to be smaller as the spatial scale increases: The contribution to the local warming can reach as high as 50% in the metropolis, remains high (~25%) in GBA, and decreases to about 10% in GHMR. In addition, this paper systematically discusses the uncertainty in urbanization contribution detection, which was often neglected in the past detection. Based on the significance tests, urbanization warming is nearly uniform throughout the day, while it exhibits distinct seasonal variation. Our study also has important implications for understanding the influences of human activities on regional climate change for other regions experiencing rapid urbanization processes. Key Points: The contribution of urbanization to regional warming is robust in homogenized SAT data and ERA5 reanalysis using different methodsThe spatial scale dependence of urbanization warming is investigated; the contribution of urbanization warming decreases when the scale increasesUrbanization contribution exhibits distinct seasonal variation based on the uncertainty assessment [ABSTRACT FROM AUTHOR]

China experienced a shift from net forest losses to gains (forest transition) between 1976 and 1981. Such transition has increased timber volume in natural forests and expanded the provision of forests ecosystem services. However, the timing, magnitude, and impact of the forest transition varied at provincial scales due to heterogeneous socio‐economic and institutional conditions. The aim of this study is to quantify the impact of spatial drivers of forest transition in China through integrated comparative and spatial regression methods. This approach allows the documentation of feedbacks and interactions of theoretical pathways to forest transition at different geographical scales, which is of relevance for large‐scale land restoration efforts. Our analysis also accounts for changes in forest volumes, a parameter that is usually not studied in the forest transition literature. Here, we used key indicators of demographic, economic, agricultural, and urbanization processes coupled with forest area data to investigate factors influencing forest transitions at multiple geographic scales between 1973 and 2013. Stepwise and geographically weighted regression models were adapted to quantify the key drivers' integrated and distributed magnitude effects on forest transition patterns, respectively. We assessed changes across forest types (i.e., primary and secondary forests, plantation forests) and investigated pathways to forest transition at provincial scales. The results indicate that increasing demand for timber and other forest ecosystem services, rising gross domestic product and population, forest policy, and increasing employment in the industry and service sectors generated multiple pathways to forest transition. The impact of those drivers varied within provinces, and some transition pathways were more relevant than others at sub‐national scales. Despite the Country scale shift to net forest gains, the loss of natural forests continued in some provinces (e.g., Guangdong, Guangxi) until recent years. The loss of ecosystem services from mature forests offset some of the benefits of China's forest transition. Coordinated forest management strategies across political jurisdictions could speed up the path to net forest gains, reduce trade‐offs of forest transitions processes, and achieve sustainable afforestation processes. Such an effort could have significant contributions to the preservation and increase of key forest ecosystem services for the Country and the world. [ABSTRACT FROM AUTHOR]

Previous studies show that the environment in the Guangdong, Hong Kong, and Macao region is under the double stress of global warming and urbanization. Here, we show that due to the increase of regional greenness, the effect of urbanization warming on surface air temperature (SAT) decreased with time and became statistically insignificant from 2004 to 2018, compared to 1979 onward; while the urbanization itself has significantly warmed land surface temperature (LST), with a warming rate of 0.14°C ± 0.04°C/10a at daytime and 0.02°C ± 0.02°C/10a at nighttime during 2004–2018, respectively. The anthropogenic heat was found to have a limited influence on SAT, but more significant and tangible effects on LST. It is essential to improve the control of additional warming effects caused by urbanization. Plain Language Summary: The Guangdong, Hong Kong, and Macao region is the most economically developed region in China, and the urbanization impact on the regional warming is frequently discussed during recent decades. We found that the urbanization warming on surface air temperature (SAT) has decreased to insignificant during the recent decade due to regional greening, while the warming of land surface temperature (LST) remains tangible. This result is related to the different effects of two moderating drivers (anthropogenic heat and vegetation index) on both SAT and LST. Thus, it is essential to increase urban greenness and reduce anthropogenic heat fluxes in parallel. Key Points: The effect of urbanization on the surface air temperature (SAT) decreases over time as regional vegetation greening increasesThe urbanization effect on the land surface temperatures (LSTs) from the long time series of satellite retrievals remains significantThe anthropogenic heat was found to have a limited influence on SAT, but more significant and tangible effects on LST [ABSTRACT FROM AUTHOR]