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There is a strong inter-annual and inter-decadal variability in time series of variables related to water abundance, such as intense precipitation, high river discharge, flood magnitude, and flood loss in China. Part of this variability can be random or chaotic, but it may well be that climate variability track plays an important role in the interpretation of the variability of water abundance. The principal aim of this review paper is to create a summary of literature-based information on links of various climate-variability drivers, i.e. natural oscillations in the ocean–atmosphere system, and the variability of characteristics of destructive water abundance in China, at a range of spatial scales (national, provincial, basin-based, municipal). The present paper reviews extensive pool of literature discussing the links between the two modes of oscillation in the ocean-atmosphere system (ENSO - El Nino-Southern Oscillation and PDO – Pacific Decadal Oscillation) and variability in time series of variables related to water abundance in China. This paper also reviews examples of extension of the database, with the help of proxies. It reviews interpretation of possible link of particular large flood events (e.g. the 1998 and the 2016 deluges) to climate variability. Also a range of issues of relevance to water management are reviewed, such as seasonal forecasting and non-stationarity of flood frequency.

Pangea is the youngest supercontinent in Earth's history, forming about 300–250 Ma ago. As supported by large amounts of geological, paleomagnetic and paleontonlogical data, there is little debate on the positions of major continental blocks in Pangea. However, controversy has long surrounded the relations of East Asian blocks with Pangea. Most Pangea reconstructions assume that the East Asian blocks were not the components of Pangea but separated from Pangea by the Paleo-Tethys Ocean. These reconstructions were mainly based on geological and paleomagnetic data before the 1990's but did not fully consider recent data, especially for major orogenic belts that formed through the subduction and closure of the Proto-Tethys, Paleo-Asian and Paleo-Tethys oceans in East Asia. To determine where, when and how these oceans were closed, and whether or not the East Asian blocks were added to Pangea, the National Natural Science Foundation of China (NSFC) set up a NSFC Major Program entitled “Reconstructions of East Asian Continental blocks in Pangea”, which started in 2012 and was completed in 2016. In the past five years, the researchers of this project carried out extensive field-based geological and paleomagnetic investigations on the East Asian blocks and their intervening mountain belts, and produced large amounts of data and competing interpretations, which provide constraints on the paleogeographic evolution of the East Asian blocks from the breakup of Rodinia to the assembly of Pangea. This forms the justification for organizing this special issue in which we collected ten papers that timely summarize these new data and interpretations and present new models for the reconstructions of the East Asian continental blocks in Pangea.

Most estimates of Chinese regional Surface Air Temperatures since the late-19th century have identified two relatively warm periods – 1920s–40s and 1990s–present. However, there is considerable debate over how the two periods compare to each other. Some argue the current warm period is much warmer than the earlier warm period. Others argue the earlier warm period was comparable to the present. In this collaborative paper, including authors from both camps, the reasons for this ongoing debate are discussed. Several different estimates of Chinese temperature trends, both new and previously published, are considered. A study of the effects of urbanization bias on Chinese temperature trends was carried out using the new updated version of the Global Historical Climatology Network (GHCN) – version 4 (currently in beta production). It is shown that there are relatively few rural stations with long records, but urbanization bias artificially makes the early warm period seem colder and the recent warm period seem warmer. However, current homogenization approaches (which attempt to reduce non-climatic biases) also tend to have similar effects, making it unclear whether reducing or increasing the relative warmth of each period is most appropriate. A sample of 17 Chinese temperature proxy series (12 regional and 5 national) is compared and contrasted specifically for the period since the 19th century. Most proxy series imply a warm early-20th century period and a warm recent period, but the relative warmth of these two periods differs between proxies. Also, with some proxies, one or other of the warm periods is absent.

This paper reviews critically the Permian–Triassic (P–Tr) fossil plants and microflora recorded in three well-studied terrestrial Permian–Triassic boundary (PTB) sections, namely Chahe, Zhejue, and Jiucaichong, and two marine–terrestrial transitional PTB sections, namely Mide and Tucheng, in western Guizhou Province and eastern Yunnan Province (WGEY), Southwest China. Distinct floral composition, abundance and diversity across the PTB allow the establishment of two terrestrial macrofloral assemblages. The Lobatannularia multifolia–Gigantoclea guiyangensis (L–G) assemblage was recognized from the upper Xuanwei Formation, while the Annalepis–Peltaspermum (A–P) assemblage from the lower Kayitou Formation. The former flora comprises 105 species in 39 genera and is late Changhsingian in age. The latter assemblage includes 18 species in 14 genera and is Induan in age. The Changhsingian assemblage is characterized by the loss of many Wuchiapingian elements of the Gigantopteris flora and an increase of the gymnosperms. Most of the Permian-type plant taxa were wiped out in the PTB crisis on land with only few relicts persisting into the Early Triassic, which saw the flourishing of Annalepis and common presence of Peltaspermum and Permian relicts of the gigantopterids. During the Permian–Triassic transition some rare gigantopterids elements as well as some Peltaspermum representatives survived the biocrisis. Annalepis a pioneering lycopsid genus in the recovery of the Triassic land plants, and its proliferation marks the recovery of land plants after the PTB crisis on land in WGEY. Accordingly, vegetation changeover across the PTB is marked by a dramatic turnover of plants on land from the Permian Gigantopteris flora to the Triassic Annalepis-dominated assemblage. Palynofloras are characterized by a dramatic drop of palynomorphs in both abundance and diversity and show a stepwise extinction pattern. Moreover, macro- and microfloras of the WGEY region indicate that humid and warm climate regime prevailed through the P–Tr transition in Southwest China. The coal forming-swamps gradually migrated westward due to marine transgressions throughout the Late Permian. The “Gigantopteris flora” also migrated from east to west and a few species can survive into the earliest Triassic in the WGEY region, but disappeared soon after.

Studies conducted over several decades have shown that solubility trapping in karst areas is an important component of the “missing carbon” in the global carbon cycle. Chinese researchers have taken advantage of their natural geography that includes numerous karst areas, representing approximately 1/7 of the global karst area, to conduct studies of solubility trapping. This paper reviews over 30 years of research progress on solubility trapping by China's researchers and summarizes the following five findings: (a) water plays an important role in the karst solubility trapping, regardless of its role as reactant or carrier; (b) the CO2 concentration gradient in the soil environment, which contains biological activity, organic matter content, pH, and temperature, affects the karst solubility trapping; (c) transfer rules for CO2 in the karst system are influenced by different land cover/land use; (d) relationships between biological metabolism and karst solubility trappings are analyzed; and (e) multiple models have been established to estimate the regional and global karst solubility trapping. This review concludes with proposals for future solubility trapping research.