Oceanography

Acceleration

Physics

Geology

Climate change

Sea level rise

Environmental science

Climatology

Sea level

Classical mechanics

Nature Climate Change

Previous studies reconstructed twentieth-century global mean sea level (GMSL) from sparse tide-gauge records to understand whether the recent high rates obtained from satellite altimetry are part of a longer-term acceleration. However, these analyses used techniques that can only accurately capture either the trend or the variability in GMSL, but not both. Here we present an improved hybrid sea-level reconstruction during 1900–2015 that combines previous techniques at time scales where they perform best. We find a persistent acceleration in GMSL since the 1960s and demonstrate that this is largely (~76%) associated with sea-level changes in the Indo-Pacific and South Atlantic. We show that the initiation of the acceleration in the 1960s is tightly linked to an intensification and a basin-scale equatorward shift of Southern Hemispheric westerlies, leading to increased ocean heat uptake, and hence greater rates of GMSL rise, through changes in the circulation of the Southern Ocean. Satellite altimetry shows global mean sea-level rise acceleration; however, sparse tide-gauge data limit understanding of the longer-term trend. A hybrid method of reconstruction for 1900–2015 shows acceleration since the 1960s, linked to increases and shifts in Southern Hemisphere westerly winds.

Persistent acceleration in global sea-level rise since the 1960s