To What Extent is Sea Level Rise Caused by Human Activity? August 14, 2019 / activist360 / Leave a comment Global sea-level rise began accelerating ‘30 years earlier’ than previously thought. Global sea-level rise began to accelerate in the 1960s, 30 years earlier than suggested by previous assessments, a new study finds.The study, published in Nature Climate Change, introduces a new technique to more accurately determine historical global sea levels by combining two different statistical approaches.It was found that the southern hemisphere, home to many developing small island nations, experienced the majority of the observed sea-level rise, lead author Dr. Sönke Dangendorf tells Carbon Brief.