Tropical marine ecosystems—including shallow coastal seas and semi-enclosed basins—sustain productive fisheries, rich biodiversity and coastal livelihoods across the pantropics. Yet these climate hotspots are being reshaped by climate change in ways that differ markedly from better-studied temperate hotspots. Places like Northern Australia are subject to monsoonal winds, cyclones, the world's largest swings in sea surface height, and highly variable river flows. They are further constrained by land barriers and circular currents that limit species' capacity to seek refuge in cooler or deeper water.
We assess how compound climate events impact tropical semi-enclosed ecosystems, drawing on long-term monitoring and Models of Intermediate Complexity for Ecosystem assessments (MICE). Our findings reveal contrasting responses among co-occurring species, alongside flip-flopping patterns tied to alternating climate regimes. For some species, climate forcing is now exceeding the bounds of historical variability, driving sustained, step-wise shifts in abundance rather than gradual decline.
Crucially, temperature is not the sole driver of variability in these ecosystems. Understanding future impacts requires resolving the interactions among multiple environmental variables: bathymetry, river discharge, sea level, temperatures, cyclones and hydrologic connectivity, whose cumulative effects shape ecosystem function. We share examples of harvest strategy reforms designed to bolster fishery resilience under climate change. Anthropogenic pressures such as river development compound these climate risks, narrowing the resilience margins of species already stretched beyond their usual environmental range.
By linking compound-event dynamics to measurable community responses, our approach offers a tractable basis for anticipating, preparing for and responding to climate shocks in tropical marine hotspots.