The Pearl River Estuary is in the geometric center of Guangdong-Hong Kong-Macao Greater Bay Area, which is one of the main battlefields to drive the high-quality development of China’s economy. This paper uses seven sets of typical satellite images in Pearl River Estuary for nearly half a century (from 1973 to 2021) to analyze the changes of coastline and sea reclamation. The results show that from 1973 to 2021, the total length of the coastline of the Pearl River Estuary increased from 240.09 km to 416.00 km, and that of the continental coastline from 186.87 km to 246.21 km (but the length of natural coastline in the continental coastline decreased from 136.91 km to 15.17 km). In the same period, the total reclamation area of the Pearl River Estuary increased by 28,256.06 ha. Before 2012, the growth rate of reclamation was generally fast. After 2012, the reclamation in China has entered a period of reflection. With reclamation was strictly controlled in the new era, only the previously approved reclamation projects and national major projects have been guaranteed, which makes the average annual growth rate of the coastline length and the reclamation area in the region show a significant downward trend. The reclamation in early days was largely for agriculture and pond culture purposes, but is shifting to transportation, industrial development, and urban construction in recent decades. This study scientifically analyzes the coastline and reclamation changes of the Pearl River Estuary in the past half century, which has a very important reference value for the next step to formulate marine ecological protection and restoration strategies, and construct a new pattern of marine space development and protection.

The length of the mainland coastline in Guangdong Province ranks first in the country, and the rapid development of the marine economy have also supported Guangdong Province’s GDP to remain at the top of the country for 35 consecutive years. The coastline has extremely important ecological functions and resource values. Guangdong Province has always attached great importance to the renovation and restoration of its coastline, continuously strengthening the ecological, disaster reduction, and tourism functions of the coastal areas. This article analyzes the main measures, achievements, and main problems of coastal protection in Guangdong Province and selects typical areas for driving force analysis. Finally, some thoughts and targeted countermeasures on the protection of Guangdong Province’s coastline are proposed, which provide useful references for comprehensively strengthening coastline protection, scientifically carrying out coastline renovation and restoration, and improving the natural coastline retention rate in the future. This can also output wisdom and experience for the construction of a maritime power under the background of land–sea coordination.

The Luzon Strait (LS) is a key region for estimating carbon sources and sinks in the South China Sea (SCS) and is highly influenced by the Kuroshio Current (KC) and typhoons. Understanding the variations in the sea surface partial pressure of carbon dioxide (pCO_2-sw) under the combined effects of typhoons and KC in this region is crucial for estimating local and regional changes in ocean carbon flux. Based on valuable in situ pCO_2-sw and remote sensing data, this study aimed to reveal the temporal variations and the physical mechanisms of pCO_2-sw variations under the comprehensive effects of both typhoons and Kuroshio Intrusion (KI) in the LS. One week after the passage of the tropical cyclone (TC) Nanmadol, the concentration in the pCO_2-sw and the influencing mechanisms varied in three different regions (W1–W3) on Transect A (120°E). In the region dominated by SCS waters (W1), the average pCO_2-sw increased by 5.1 μatm after TC, which was mainly due to the TC “Wind Pump” inducing strong vertical mixing, which brought dissolved inorganic carbon (DIC)-rich deeper water up to the surface. In the region affected by KC (W2 and W3), pCO_2-sw decreased after the TC (−8.2 μatm and −1.8 μatm, respectively) with TC-enhanced KI because the invasion of lower pCO_2-sw of Kuroshio waters inhibited the TC-induced upwelling. More significant TC-induced upwelling (W3) would alleviate the decrease in pCO_2-sw caused by the TC-enhanced KI. This study is a rare case providing a better understanding of the variations in pCO_2-sw under TC-enhanced KI, which provides support for regional climate change prediction and carbon flux estimation in the western boundary current regions.