A new study published in the Proceedings of the National Academy of Sciences reveals that the rate of sea level rise is greater than previous studies have suggested. This scientific analysis has found that sea levels are rising three times as quickly as they were throughout the 20th century.
Details of the Study
Sönke Dangendorf, from the University of Siegan in Germany, is the researcher who led the study. He collaborated with other scientists from institutions in the Netherlands, Norway, France and Spain. As a team they found that “we have a much stronger acceleration in sea level rise than formerly thought.” They are not the first study to find that the Earth’s sea levels are rising, but the importance of their study lies with the rate of increase they observed with sea level rise.
Before 1990, the rate of sea level rise was about 0.43 inches per decade, or 1.1 millimeters per year. During the time between 1993 and 2012, these numbers rose to 1.22 inches per decade/3.1 millimeters per year. According to Dangendorg, the major reason for this accelerated rate in sea level rise is from melting ice sheets in Greenland and Antarctica. Back in the 20th century, the major reason for sea level rise was from land-based glaciers melting and the expansion of warming seawater. But now the 21st century is faced with more than they bargained for.
How the Study Compares to Others
Other scientists have also looked into the rate of sea level rise from 1900-1990. One of the limiting factors for this analysis is the lack of satellite records during this time period. Dangendorg and his team derived sea level records for the 20th century by analyzing the data from tide gauges spread around the world. There were no satellite records to use, so instead they adjusted the results of local tide gauges based on factors that affect sea level rise in a given area. In comparison, Robert Kopp’s 2015 study estimated a sea level rise rate of 1.2 millimeters per year for the 20th century. However, other researchers found rates of 1.6 to 1.9 millimeters per year.
Kopp is a sea level researcher from the Rutgers University who is interested in these disparities. In the past five years he has seen estimates that have a 21st century rate higher than 3.1 millimeters per year. But he believes that “those higher rates over a short period of time probably include some level of natural variability as well as continued, human-caused acceleration”. With the disparities between figures, it has been difficult to gauge the acceleration rate of sea level rise. Overall, scientists agree that sea levels are rising, but they are still debating the details of its rate of acceleration.
A Glimpse in the Future of Sea Level Rise
Despite the debates in numbers and figures, the take-away message from these studies is the need look at the bigger picture. Climate change is a global issue and everyone will be affected, one way or the other. According to Dangendorf, “sea levels will continue to rise over the coming century, no matter whether we will adapt or not, but I think we can limit at least a part of the sea level rise. It will further accelerate, but how much is related to how we act as humans”. Some studies have predicted that sea levels could rise as much as 5 to 15 millimeters per year/1.97 to 5.9 inches per decade in extreme scenarios of global warming. As a society we need to decide whether we’ll take charge to reduce our greenhouse gas emissions or wait until we reach the point of no return.