Human forced climate change through fossil fuel burning now presents a serious threat to the world’s coastal cities and island nations. Diverse regions of the world are now facing increased inundation at times of high tide and during storms. Unfortunately, this trend is only worsening. And depending on how much additional fossil fuel is burned, we could see between 2 to 10 feet or more of sea level rise this Century.

(Sea level rise analysis and update based on information provided by AVISO, Climate Reanalyzer, and the work of Dr. James Hansen.)

As the Earth has steadily warmed to 1.1 C above 1880s averages, the oceans of our world have risen. At first, the rate of rise was very mild — a mere 0.6 mm per year during the early 20th Century. However, as the rate of global warming increased and the oceans took in more heat, the middle 20th Century saw sea level rise increase to 1.4 mm per year. By the end of the 20th Century, the polar glaciers had begun to melt in earnest. And from 1990 to the present day, the rate of sea level rise has accelerated to 3.3 mm per year.

Due to more warm water invading the basal regions of glaciers and more ice bergs calving into the world ocean, the annual rate at which ocean levels increase continues to jump higher. And during recent years — from 2010 to 2018 — the world ocean has risen by nearly half a centimeter each year (4.6 mm).

(Since 2010, the rate of sea level rise has again accelerated. And it appears that El Nino years have recently tended to produce strong upward swings in the annual rate of increase. This may be due to El Nino’s tendency to set up stronger cycles of energy transfer to the poles. NOAA presently indicates a 50 percent chance that a mild to moderate El Nino will emerge during the winter of 2018-2019. Will we see another sea level spike at that time should El Nino emerge? Image source: AVISO.)

Now both island nationals and coastal cities face the increasing danger of rising tides, of inundation, and of loss of lands and infrastructure. A rapid switch to renewable energy and away from fossil fuel burning is needed to save many regions. However, due to presently high greenhouse gas accumulation, it is likely that some zones will be lost over the coming decades.