Uncovering an anthropogenic sea-level rise signal in the Pacific Ocean

Internal climate variability across a range of scales is known to contribute to regional sea-level trends(1-7), which can be much larger than the global mean sea-level trend in many parts of the globe. Over decadal timescales, this internal variability obscures the long-term sea-level change(3,6,8), making it difficult to assess the effect of anthropogenic warming on sea level. Here, an attempt is made to uncover the sea-level rise pattern in the tropical Pacific Ocean associated with anthropogenic warming. More specifically, the sea-level variability associated with the Pacific Decadal Oscillation is estimated and removed from the regional sea-level trends computed from satellite altimetry measurements over the past two decades. The resulting pattern of regional sea-level rise uncovered in the tropical Pacific Ocean is explained in part by warming in the tropical Indian Ocean, which has been attributed to anthropogenic warming(9). This study represents one of the first attempts at linking the sea-level trend pattern observed by satellite altimetry to anthropogenic forcing.