Over the last 2 decades, there has been a dramatic increase in research activities and in the number of publications devoted to monsoon variability. Speleothem and ice-core records, together with deep-sea and terrestrial sediments, have enhanced the resolution of paleoclimate proxy records to an unprecedented level. In recent years (2013–2016), seven deep-ocean drilling expeditions were completed by IODP (Integrated Ocean Drilling Program and International Ocean Discovery Program) to explore the Cenozoic history of the Indian, East Asian and Australian monsoons (Fig. 1, Table 1). Earlier, between 1986 and 1999, at least 10 ODP (Ocean Drilling Program) cruises carried out drilling in African, American and Asian monsoon regions as well (Fig. 1, Table 2).

Traditionally, the variability of the monsoon has been studied almost exclusively on regional scales, by both the modern and paleo-monsoon communities. With the application of remote sensing and other new techniques over the last decade, the concept of the global monsoon has been introduced as a global-scale seasonal reversal of the three-dimensional monsoon circulation associated with the migration of rainfall in the monsoon trough and the intertropical convergence zone (ITCZ) (Trenberth et al., 2000; Wang and Ding, 2006). In an effort to understand better the dynamics of monsoon variability, the “Global Monsoon and Low-Latitude Processes: Evolution and Variability” working group was established by PAGES (Past Global Changes) in 2007.

This working group conducted two successive symposia in 2008 and 2010 in Shanghai (Wang et al., 2009, 2012a), bringing together paleo and modern climatologists, as well as data producers and modelers. They compared monsoon studies from all regional monsoon systems and identified their similarities and differences across an exceptionally broad range of timescales, from interannual to tectonic, and tried to unravel the mechanisms causing variations in the global monsoon system and regional monsoon deviations from the global trend. As a result, a special issue with 13 contributions (Wang et al., 2012b) and two synthesis papers (Wang et al., 2014, 2017) were published. Obviously, the relevant community felt that the time was right for an international workshop to synthesize the research progress of monsoon-related IODP and ODP expeditions from a new viewpoint of the global monsoon system.

After 2 years of preparation, the IODP-PAGES Global Monsoon Workshop took place on 7–9 September 2017, in Shanghai, co-sponsored by IODP, PAGES and IODP-China. Forty-eight scientists from 12 countries participated in the workshop, presented the scientific findings from the seven recent IODP monsoon-related expeditions (Table 1) as well as the previous ODP cruises (Table 2), discussed research directions, and made recommendations for the future IODP science program (Fig. 2).

The workshop started with presentations given by the PAGES Global Monsoon Working Group. On the basis of observation and proxy data, the working group found that the regional monsoons can vary coherently, although not perfectly, at various timescales. Monsoon variability may arise from external forcings or internal feedback processes within the climate system (Fig. 3). Within the global monsoon system, each subsystem has its own features, depending on its geographic and topographic conditions. Discrimination between global and regional components in the monsoon system is a key to revealing the driving factors in monsoon variations.

In the IODP Science Plan for 2013–2023, investigating the monsoon is listed in “Challenge 3”, essentially as a factor controlling the regional patterns of precipitation (IODP, 2011). Accordingly, the recent monsoon-related IODP expeditions largely focused on the variations of the global hydrological cycle. For example, ocean drilling addressed this topic beginning ∼ 30 years ago with ODP Leg 117 to the Arabian Sea, which established a regional paleo-monsoon history from monsoon wind-driven upwelling records. IODP Expedition 353 in 2014 targeted paleo-monsoon reconstruction based on salinity gradients induced by summer monsoon precipitation (Clemens et al., 2016). In the Sea of Japan during ODP Leg 127, a 0.9 Ma sequence recovered 30 years ago was marked by alternation of dark and light layers in deep-water sediments, ascribed to millennial-scale variability of East Asian summer precipitation. In 2013, IODP Expedition 346 recovered a much longer monsoon record back to the middle Miocene at about 12 Ma (Tada et al., 2015). In general, ODP-IODP drilling has yielded the longest high-resolution records of regional monsoons, providing the basic data for a global synthesis of monsoon variations from tectonic, orbital, down to millennial timescales.

A number of questions were discussed during the workshop, such as applicability of the global monsoon concept at geological timescales, monsoon response to external forcing and internal feedback, initiation of the current monsoon systems, the use and interpretation of monsoon proxies, and the role of monsoonal circulation in the global climate system. In order to promote the development of global monsoon research and to elucidate its role in the hydrological cycle at various geological timescales, the workshop came up with the following recommendations for future IODP activities to be incorporated into the IODP Science Plan beyond 2023.