We summarise the main findings of the Global Wetland Outlook (2018) about the status of wetlands, including their biota and ecosystem services, the drivers of change in wetlands, and the responses being adopted by the Ramsar Convention. The Outlook, which is the Ramsar Convention’s flagship publication, generally paints a bleak picture of wetland status. On the basis of these findings, we identify 10 key issues for decision makers to consider and recommend actions to implement so as to reverse the overall downward trends for wetlands. A switch from documenting the change in wetland biodiversity towards more emphasis on taking decisions is needed to implement effective responses and reverse the negative trends for wetlands. Although further data are needed, we contend that failure to place greater emphasis on effective responses could lead to the Convention becoming an irrelevant force for the wise use of wetlands.

Indicators of status and trends in wetland extent are essential for monitoring progress towards the environmental targets set by the Convention on Biological Diversity (CBD), the United Nations Sustainable Development Goals (SDGs) and the Ramsar Convention on Wetlands. Here, we test the value of the Wetland Extent Trends (WET) index as an updatable indicator of trends in wetland area and its application to global and regional scale assessments and national reporting. We expand the indicator to include a regional trend for Latin America and the Caribbean and a global human-made WET index. Based on a sample of over 2000 wetland records, natural wetland extent declined on average by 35% globally, at an increasing rate from 1970 to 2015. Human-made wetlands, however, increased by 233% from 1970 to 2014. The continuing decline in natural wetland extent suggests that global targets will not be achieved without significant further efforts.

The biodiversity and high productivity of coastal terrestrial and aquatic habitats are the foundation for important benefits to human societies around the world. These globally distributed habitats need frequent and broad systematic assessments, but field surveys only cover a small fraction of these areas. Satellite-based sensors can repeatedly record the visible and near-infrared reflectance spectra that contain the absorption, scattering, and fluorescence signatures of functional phytoplankton groups, colored dissolved matter, and particulate matter near the surface ocean, and of biologically structured habitats (floating and emergent vegetation, benthic habitats like coral, seagrass, and algae). These measures can be incorporated into Essential Biodiversity Variables (EBVs), including the distribution, abundance, and traits of groups of species populations, and used to evaluate habitat fragmentation. However, current and planned satellites are not designed to observe the EBVs that change rapidly with extreme tides, salinity, temperatures, storms, pollution, or physical habitat destruction over scales relevant to human activity. Making these observations requires a new generation of satellite sensors able to sample with these combined characteristics: (1) spatial resolution on the order of 30 to 100-m pixels or smaller; (2) spectral resolution on the order of 5 nm in the visible and 10 nm in the short-wave infrared spectrum (or at least two or more bands at 1,030, 1,240, 1,630, 2,125, and/or 2,260 nm) for atmospheric correction and aquatic and vegetation assessments; (3) radiometric quality with signal to noise ratios (SNR) above 800 (relative to signal levels typical of the open ocean), 14-bit digitization, absolute radiometric calibration <2%, relative calibration of 0.2%, polarization sensitivity <1%, high radiometric stability and linearity, and operations designed to minimize sunglint; and (4) temporal resolution of hours to days. We refer to these combined specifications as H4 imaging. Enabling H4 imaging is vital for the conservation and management of global biodiversity and ecosystem services, including food provisioning and water security. An agile satellite in a 3-d repeat low-Earth orbit could sample 30-km swath images of several hundred coastal habitats daily. Nine H4 satellites would provide weekly coverage of global coastal zones. Such satellite constellations are now feasible and are used in various applications.