The new findings show sea level rise is 25% slower than previous models. The picture shows the coastline of Miami.
One of the serious consequences of “global warming” that has been widely discussed by scientists in recent years is that as sea temperatures rise on all sides of Antarctica, glaciers will melt faster, causing sea levels to rise and flooding some low-lying coastal cities.
Existing estimates of sea level rise are based on climate change models that are widely used by the scientific community. But these models are relatively crude, and as scientific research progresses and supercomputers are used, scientists have the ability to consider more and more details to continually improve the accuracy of the models.
A new study that added the effect of ocean eddies on temperature found that the rise in seawater temperature is much smaller than previous model estimates, showing that over the next 100 years, sea level rise will be about 25 percent less than previous model estimates.
Henk Dijkstra, a professor at Universiteit Utrecht in the Netherlands, who has been improving climate research models for years, said, “The high-resolution simulation system (we use) can determine ocean circulation more accurately.”
Their new model takes into account the effects of ocean eddies. An eddy is a vortex within the ocean, varying from 10 km to 200 km in diameter, that plays an important role in the variation of seawater temperature and salt transfer.
Add this factor to existing ocean climate models to more accurately reflect changes in seawater temperature on all sides of Antarctica, which is key to the rate of glacial melt.
Dykstra explained that there is also the protective role of the ice shelf to consider. Antarctic land glaciers are surrounded on all sides by ice shelves, which are thick sheets of ice that extend from the land to the sea. These ice shelves slow down the speed of land glaciers slide into the ocean. Only the accelerated melting of the ice shelves would cause the land glaciers to slide faster into the ocean, which would then lead to a rise in sea level.
The new models show seawater temperature changes that differ significantly from existing models, with some regions near Antarctica even cooling rather than warming, Kestra said.
The new model shows much less mass loss from land glaciers than existing models after accounting for the effects of eddies on temperature and the protective effect of ice shelves: sea level rise over the next 100 years is only 25 percent of existing model estimates.
Co-investigator René van Westen says that eddies are a detailed factor that has an important impact on the final results, but requires the use of a large number of calculations. It took them a year to complete these calculations using SURFsara, a supercomputer based in Amsterdam, to get these more accurate results. “Although sea levels are still rising, the results of this study are good news for areas with low relief.”
The study was published April 9 in the journal Science Advances.
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