Climate models show that human activities, like burning fossil fuels, are responsible for 87 percent of the sea level rise since 1970 that’s been caused by swelling volume of the upper ocean. Natural forces, like solar radiation and volcanic activity, are responsible for the remainder of the increase in the upper ocean’s share of warming-induced sea level rise.
“The fact that greenhouse gases from human activity have an impact (on thermosteric sea level rise) is well known but nobody up to now has been worried about putting a number on that,” said Marta Marcos, a researcher at the Mediterranean Institute for Advanced Studies in Mallorca, Spain and the lead author of the new research. The analysis is the first to quantify how much of an influence human activity has had on thermosteric sea level rise in the top layer of the ocean, she added.
Figuring out how much of an influence humans are having on specific climate variables, like thermosteric sea level rise, is important for assessing what will happen as the planet warms, Marcos said. Sea level rise can cause flooding and erosion in low-lying coastal areas.