Drivers and implications of change in global ocean health over the past five years

Abstract

Growing international and national focus on quantitatively measuring and improving ocean health has increased the need for comprehensive, scientific, and repeated indicators to track progress towards achieving policy and societal goals. The Ocean Health Index (OHI) is one of the few indicators available for this purpose. Here we present results from five years of annual global assessment for 220 countries and territories, evaluating potential drivers and consequences of changes and presenting lessons learned about the challenges of using composite indicators to measure sustainability goals. Globally scores have shown little change, as would be expected. However, individual countries have seen notable increases or declines due in particular to improvements in the harvest and management of wild-caught fisheries, the creation of marine protected areas (MPAs), and decreases in natural product harvest. Rapid loss of sea ice and the consequent reduction of coastal protection from that sea ice was also responsible for declines in overall ocean health in many Arctic and sub-Arctic countries. The OHI performed reasonably well at predicting near-term future scores for many of the ten goals measured, but data gaps and limitations hindered these predictions for many other goals. Ultimately, all indicators face the substantial challenge of informing policy for progress toward broad goals and objectives with insufficient monitoring and assessment data. If countries and the global community hope to achieve and maintain healthy oceans, we will need to dedicate significant resources to measuring what we are trying to manage.

Essential ocean variables for global sustained observations of biodiversity and ecosystem changes

“…Biological EOVs therefore need to be carefully chosen to address a broad number of stakeholders with a consistent nomenclature and clearly defined standards. They should address fundamental characteristics of the biological components of marine ecosystems that can be combined into indicators to (1) represent the complexity of real‐world natural systems, (2) track temporal and spatial changes in the state of the environment, (3) evaluate management performance, (4) deliver information and products to scientific and policy audiences (Hayes et al., ) and (5) assess progress towards international goals and targets (Halpern et al., ; Tittensor et al., ; Walpole et al., ). With these criteria, GOOS defines biological/ecological EOVs as those sustained measurements that are necessary to assess the state and change of marine ecosystems, address scientific and societal questions and needs, and positively impact society by providing data that will help mitigate pressures on ecosystems at local, regional and global scales .…”

Perspectives on a Global Observing System to Assess Ocean Health

“…In the case of ocean ecosystem health assessment, this requires scientists working with policy makers and regulators, at local, national or intergovernmental levels, to drill down from "metaphor level" objectives and indicators to those that can be objectively and robustly evaluated. Halpern et al (2017) emphasize that currently "all indicators face the substantial challenge of informing policy for progress toward broad goals and objectives with insufficient monitoring and assessment data. If countries and the global community hope to achieve and maintain healthy oceans, we will need to dedicate significant resources to measuring what we are trying to manage".…”

Quantifying uncertainty in the wild‐caught fisheries goal of the Ocean Health Index

“…The Ocean Health Index (OHI) (Halpern et al., ) is a comprehensive, ecosystem‐level indicator that aggregates many socioeconomic and biological indicators to assess the health of the global oceans. The OHI has been calculated globally every year since 2012 (Halpern et al., ), and the framework has been adopted at regional and local scales to inform regional policy and decision‐making (Burgass et al., ; Elfes et al., ; Halpern et al., ; Lowndes et al., ). The OHI itself is one indicator used for tracking Aichi Biodiversity Targets (Target 10) and newly ratified UN Sustainable Development Goals (SDG 14; Sachs, Schmidt‐Traub, Kroll, Lafortune, & Fuller, 2018).…”