Written by on December 5, 2022

A twitter post claiming that ocean levels are the same as they were 1000 years ago is false.

“There is no climate change, only normal cycles with small differences. The ocean levels are the same as carved in the cliffs 1k years ago, exact. We are in the small natural cooling cycle and the northern cap has expanded recently and oil never runs out. It is bio,” reads the claim.

Sea levels rose 10 meters above present levels during earth’s last warm period 125,000 years ago. This is according to new research that offers a glimpse of what may happen under our current climate change trajectory.

A publication made by Nature Communications shows that melting ice from Antarctica was the main driver of sea level rise in the last interglacial period, which lasted about 10,000 years.

The publication reveals that Antarctica which hasn’t been seen as a contributor towards sea level rise to actually be one of the biggest contributors. This is simply because the ice sheets from Antarctica have the ability to change quickly in a manner that tends to have massive future effects to the coastal communities and infrastructure.

The earth moves in cycles, and the cycles consist of cold glacial periods as well as ice ages, that comes about when large ice sheets cover large parts of the world, and warmer interglacial periods when the ice melts and sea levels rise.

For the past 10,000 years, the earth has been undergoing an interglacial period, however, in the past 200 years, greenhouse gas emissions have caused faster and extreme climate changes than the ones experienced in the last interglacial.

This therefore gives an impression that the previous rise in sea levels provide low-end predictions of expected future happenings.

Temperatures were 1℃ higher 125,000 to 118,000 years ago when the earth underwent the last interglacial, compared to the year 2019, and this happens to be similar to projections for the near future.

During the last interglacial period, sea levels rose approximately 10 meters above the present level as a result of ice thaw. This happened twice, first in Antarctica and later in Greenland a thousand years ago.

Sea level rise over the past 150 years was estimated at 0.3 meters, but this was far much exceeded by the 3 meter rise per century during the last interglacial. Antarctica occurred at the start of the interglacial as a result of warming of the Southern Ocean. This massively interfered with the ocean’s circulation, hence resulting in warming in the northern polar region and triggering ice thaw in Greenland.

By the year 2100 (relative to 2000), depending on the greenhouse gas emissions pathway followed, total sea level rise is projected at 70-100 centimeters. This is in consideration to the current annual sea level rise estimated at 3 millimeters. This is according to data collected from tide gauges this century, as well as satellite data since the 1990s.

Since 1900, seas have risen a little over 8 inches, but the rise is accelerating: A quarter of it has happened since 2006. In a report released by the Intergovernmental Panel on Climate Change (IPCC) in 2021, scientists determined global average sea level is now rising around 0.15 inch (3.7 millimeters) each year. The IPCC projected with “medium confidence” that it would rise another 15 to 30 inches by 2100, and will keep rising for centuries.

Source: World Economic Forum 

We looked into this claim stating that ocean levels are the same as they were 1000 years and found it to be false.

This fact-check was produced by Sky 106.1 FM with support from Code for Africa’s PesaCheck, International Fact-Checking Network, and African Fact Checking Alliance network.

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