The rise in sea level during the last decade of the 20th century and the first of the present has been significantly higher than that estimated by the forecasts of experts, according to a study led by Carling Hay and Eric Morrow, from the Department of Planetary Sciences and Earthlings from Harvard University and published in the journal Nature .
Research in the past had overestimated the rise in sea levels between 1900 and 199 0 by as much as 30%. However, the latest data suggest that the calculations made on the oceanic flood since 1990 are correct and prove that the level of the sea changes at a faster rate than expected.
“Our research shows that sea level acceleration over the past century has been greater than previous research had anticipated. The problem is more serious than we initially thought,” says Morrow. According to Hay, scientists now know that most of the world’s ice sheets and mountain glaciers are melting due to rising temperatures, causing global sea level rise.
While previous estimates put the annual rise in sea level at 1.5 to 1.8 millimeters during the 20th century , Hay and Morrow put it at 1.2 millimeters between 1901 and 1990. But after that year , the community Scientists agree that the annual rise has been about 3 millimeters, which implies a marked acceleration of this phenomenon associated, among others, with climate change.
These experts believe that it is now necessary to adopt a “completely new perspective” . Normally, estimates of sea level rise are made by taking records with tide gauges of the variations suffered by the subregions into which the oceans have been divided. These records, to which other more specific complementary data are added, are used to estimate the average rise in sea level in each subregion, which in turn are combined to produce a global average.
“But these simple averages are not representative of the true global value. Tide gauges are located on the coasts , so there are large ocean areas that are not included in the estimates,” explains Hay.
According to the study, sea level changes for several reasons, such as the lasting effects of the last ice age, the warming and expansion of the ocean due to global warming, variations in water circulation or melting ice. Hay and Morrow made their new forecasts by looking at a global data set.
