Global warming: sea level rises faster than expected

mybestnews (2)in #global • 7 years ago

Global warming: sea level rises faster than expected

Flood in Miami in November 2013. The large city of Florida will be affected by rising sea levels due to global warming.
Zachary Fagenson

Ocean levels could rise by more than 60 centimeters by 2100 according to a study based on information collected by satellite for 25 years, which confirms the projections of the Giec.

The pessimistic forecasts of scientists are confirmed. The annual rise in ocean levels could more than double by the end of the century, according to the findings of the American Academy of Sciences (PNAS) , released Monday.

A pace that is accelerating

The rate of sea level rise is currently estimated at between three and four millimeters per year. It could reach ten millimeters each year according to the American scientific body in the coming years. PNAS scientists say this is a "conservative estimate".

In addition, the accelerated melting of Greenland and Antarctica will also contribute to a rise in sea level of at least 60 centimeters more, threatening the coastal cities of the planet. It could endanger drinking water supplies through saltwater intrusion into the aquifers, notes Newsweek , who interviewed one of the authors of this study, Steve Nerem of the University of Colorado.

Observation data confirm IPCC models

Climate change is driving ocean rise through two phenomena: the rapid melting of ice in the poles and the increased concentrations of greenhouse gases in the atmosphere. This last phenomenon warms the temperature of the water. But hot water - less dense than cold water - takes up more space. This mechanism is already responsible for half of the seven-centimeter increase over the past 25 years, according to Professor Nerem.

The results of this work, based on 25 years of satellite-based observational data, "are broadly in line with the projections of the IPCC AR5 report, the UN Panel of Experts on Climate Change," published in December. 2014, from computer projections.

A disturbing rise

The study does not take into account other factors, such as the El Niño phenomenon that increases water temperature and precipitation, or a volcanic eruption such as that of Pinatubo in 1991, which, conversely, the cools.

"Some people refuse to act on climate change because they do not trust mathematical models," Steve Nerem told Inside Climate News , "[ Our ] observations confirm these modeled projections."

The last time the earth was as hot as it is now, about 125,000 years ago, the sea level was 6 meters higher than today, the scientist adds. "The question is how long will we get there?"

Source: lexpress.fr