Timing of emergence of modern rates of sea-level rise by 1863
Study key findings & significance
- Modern global sea level rise patterns emerged along with the Emancipation Proclamation in 1863.
- The sea level rise coincides with the increase of coal use during and after the U.S. Civil War, when industrialization was taking hold as evidenced by the proliferation of steamboats and railroads.
- The technology arguably resulted in rising sea levels due to warming oceans and glacier melt.
“Sea level rise is a really important indicator of broader climate change. If we can estimate when sea-level rise really emerged from background variability, we can pinpoint this onset of a significant period of climate change.”
- Jennifer Walker, Professor in the Department of Earth and Planetary Sciences at Rutgers University
Sea-level rise is a significant indicator of broader climate changes, and the time of emergence concept can be used to identify when modern rates of sea-level rise emerged above background variability. Yet a range of estimates of the timing persists both globally and regionally. Here, we use a global database of proxy sea-level records of the Common Era (0–2000 CE) and show that globally, it is very likely that rates of sea-level rise emerged above pre-industrial rates by 1863 CE (P = 0.9; range of 1825 [P = 0.66] to 1873 CE [P = 0.95]), which is similar in timing to evidence for early ocean warming and glacier melt. The time of emergence in the North Atlantic reveals a distinct spatial pattern, appearing earliest in the mid-Atlantic region (1872–1894 CE) and later in Canada and Europe (1930–1964 CE). Regional and local sea-level changes occurring over different time periods drive the spatial pattern in emergence, suggesting regional processes underlie centennial-timescale sea-level variability over the Common Era.