Current rates of sea level rise are not even outside the range of natural variability. – Watts Up With That?
Via Kenneth Richard
ONE new research reminds us that, 8,200 years ago, near-global sea levels rose 6.5 metres in just 140 years. That’s 470 cm per century, 4.7 cm per year, during a period when CO2 levels were considered “safe” and stagnant at 260 ppm.
Image source: Nunn et al., 2024
To put this rate of change into perspective, global sea levels rose at a rate of 1.56 mm per year from 1900 to 2018, including a rate of 1.5 mm per year in the more recent period from 1958 to 2014 (Frederikse et al., 2020, Frederikse et al., 2018). This is just under 16 cm per century or sixteen-tenths of a centimeter (0.16 cm) per year.
Image source: Frederikse et al., 2020 And Frederikse et al., 2018
The net melting of the Greenland Ice Sheet (GIS) is thought to be the largest contributor to sea level rise in recent decades. But, to put the GIS change into context, the total ice sheet melting contribution to sea level rise is only 1.2 total cm from 1992-2020 (Simonsen et al., 2021).
Image source: Simonsen et al., 2021
The Earth’s natural rate of sea level rise, which periodically reaches 4.7 cm per year, is thus 30 times greater than the “artificial” rate in the modern period (1900-2018), which is 0.156 cm per year.
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