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Melting ice is causing the ocean to sink, worrying about new study reports

Scientists have identified another unexpected consequence of climate change: warming temperatures are causing polar ice to melt, and this additional weight causes the bottom of the ocean to sink. This process also exacerbates sea level rise.

Like octopuses, the arms of climate change are long, long-range and sticky. If there is anything that recent studies have shown, it is that rising temperatures are causing a lot of planetary changes, often with unpredictable effects. For example, climate models clearly showed that rising temperatures will melt polar ice. But it is much harder to predict the effects that this extra water will have on the rest of Earth's systems.

Now, geoscientist Thomas Frederikse of the Delft University of Technology in the Netherlands and his colleagues report that melt water is adding extra weight to the seabed,

We tend to think of the Earth as a firm sphere and immutable. But geologically, our planet is a very dynamic place.

"The Earth itself is not a rigid sphere, it is a distorting ball," Frederikse said. "With climate change, we do not just change the temperature."

The researchers knew that an excess of weight could crush the Earth, but they wanted to know how could be crushed, and this is where the surprises began.

Changes in a) the seabed b) relative sea level and c) sea level as measured by satellites when considering the effect of additional oceanic mass on seabed height. Observe how the change in sea level in relation to the seabed is really negative for the Arctic, that is because the seabed is increasing slightly due to the loss of mass. Image: Frederikse et al. 2017

They found that the effect is so pronounced that the current models are slightly off, and the rise in sea level is even more significant than we expected. The measurement problem stems from the fact that satellite altimeters measure the height of the ocean surface in relation to the center of the Earth, but do not see what happens with the seabed. Therefore, researchers needed a different type of data.

"We have had measurements of sea level rise for more than a century," Frederikse told Earther. "You put an instrument on the bottom of the sea and you see how far the sea level changes with respect to the bottom." The satellites that orbit the Earth measure the sea level from space, we wanted to see how big the difference is.

Frederikse's team analyzed data from Greenland and Antarctic ice sheets, as well as changes in surface water storage due to dams, irrigation and other human activities. After a large number of crunching and modeling methods, they found that the extra cargo in the oceans was significant enough to cause an additional sink of 0.1 mm / year between 1993 and 2014, or 2.1 mm during the entire period. This fall was not uniform, reaching 1 mm / year over the Arctic Ocean and 0.4 mm / year in the South Pacific.

This might not seem like much, but this is the whole ocean we are talking about There is no immediate reason to worry, but if you take into account the magnitude of the process, a red flag is raised. The phenomenon is also expected to increase in intensity as more and more ice begins to melt.

For scientists, this study also suggests that there is a significant source of error when it comes to sea level rise: it is an amplification effect of 8% that I have not considered so far.

"The effect is systematic and relatively easy to explain," write Frederikse and his co-authors in their study recently published in Geophysical Research Letters adding that it is likely to become a more obvious problem as the study progresses. climate change. "In a climate of future warming, the rise in sea level induced by the ice sheets will increase, and therefore, the magnitude of the bias due to the deformation of the elastic ocean floor will grow."

Taking a step back and looking at the larger image, There is a clear message behind this study: the effect of humanity on the planet is profound and lasting, affecting all the ecosystems of the planet. The deformation of the ocean floor turned out to be a shocking and unexpected process, who knows what else we lack?

The study was published in Geophysical Research Letters .

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