Alarms over rising oceans continue to sound. Politicians, actors, authors, and “climate activists” warn us regularly that the massive ice sheets in the Antarctic, and the Arctic, are melting. They remind us that in a matter of decades, oceans will rise to the point where they will destroy many coastal cities, and the process would become “irreversible.” The International Panel on Climate Change (IPCC) and the media have speculated and prophesied that by 2100, we would have ocean levels between five to ten feet higher. Graphic photoshopped pictures of New York skyscrapers show buildings flooded several floors high. Miami is shown vanishing under the sea. All said to be a result of increasing CO2 followed by melting ice resulting in a rise in our ocean levels. Most of our readers suspect great exaggeration but do not understand the complexity of the various variables that impact what we see as our sea levels.
Shut off the alarms and let’s get back to science and examine the fundamental data and facts to see where the levels of our oceans are actually going. Looking at Figure 1 we immediately notice that in the last 140 years, the oceans have risen nearly ten inches, an average of seven inches per century for which visual records show to have been the case for at least the past 800 years.
Now compare Figure 1 to Figure 2 and see the close correlation between the rise in ocean level with the increase in known ocean surface temperatures. In Figure 3 we see that the volume of water increases with a rise in temperature. This data shows that sea level has risen about 7 inches per century, which is about the same rate of temperature increase at the ocean surface. Nothing special here just simple physics.
The assertion that the melting polar ice is the cause of the ocean level rise is contradicted by the scientific community and even the UN/IPCC which said in their 5th report “Water volume rises with temperature because of thermal expansion—another primary driver of sea-level rise.”
But knowing the precise sea level rise due to this phenomenon depends on many unknowns, such as the bulk of the Earth’s water, its temperatures, its densities, the influence of the many ocean bottom volcanic and tectonic events, to name a few. The margin of error in these assumptions make precise prediction impossible.
However we surely know that melting floating ice can’t add measurably to ocean levels. We know from grade school that 90 percent of an iceberg, or any floating ice, is below the waterline while 10 percent is above because water expands as it becomes solid ice. This is shown in Figure 4. The ice is 10 percent less dense than the water so it floats. When it melts back into the water it takes up the same space as before. If you have not done it yet simply fill a glass with ice and water and mark its upper level. When all the ice is melted the level will be the same.
What about the melting of glaciers? The Antarctic contains about 90 percent of the world’s ice mass. Forty four percent of that Antarctic ice is floating at the coastal edges, while 50 percent sits on land and can be several miles thick. Historical data confirms that there are zero days per year where the temperature averages above freezing. Therefore little or no water from that continental Antarctic ice ever reaches the oceans. During bright and sunny days, a small amount of surface and shoreline ice is turned by the the sun directly into water vapor, a process called sublimation, never passing through the water state. When the sublimated water vapor reaches the cold Antarctic air, the vast majority of it quickly turns to snow and falls back onto the glacier. Since winds blow very little over the Antarctic ocean almost none ends up as water in the ocean.
Coastal Antarctic ice, dramatized with films, photos, and articles in newspapers, press, and the TV showing large ice sheets tumbling into the ocean, do actually contribute to sea rise but let’s see just how much . These dramatic falling cliffs are not caused by global warming air. The melting is occurring at the waters edge by the warmed Pacific Ocean. Here the water splashes and melts and gouges caverns in the ice, forming large ice shelves or overhangs. This process continues until the weight of the overhang is heavy enough to cause the ice to break and tumble off. Some of this ice will melt into the oceans and will cause some water level rise, but the volume is unmeasurably small.
NASA published a study on October 30, 2015, saying that Antarctica is accumulating ice at a rate of about 112 billion tons per year. It has already replaced all the ice that melted in the previous several decades. Another NASA study reports an increase in the rate of Antarctic snow accumulation. Currently, enough continental ice is accumulating to outweigh the losses caused by its shrinking coastal glaciers says Jay Zwally, in the Journal of Glaciology.
Yes, there was substantial glacial melting in Greenland, Alaska, and other northern hemisphere locations, which added some waters to the oceans during the warming of the past several decades. However, these glaciers tend to melt and then increase in about twenty-year cycles, depending on the local conditions. A number of these glaciers are now growing at a significant rate, like the famed Jakobshavn glacier in Greenland. A world scorecard is kept that shows which glaciers are melting, and which are growing. The long-term batting average seems to be about 50 percent.
Besides water temperature, other factors need to be accounted for when we say the ocean level is rising or falling. At the local level, the ocean can appear to “increase” or “decrease” due to changes on the land, along with other unique factors in the surrounding areas that have nothing to do with water temperature or polar ice melting. These are caused by land settling, such as we see in downtown Boston, where the landfill of 150 years ago keeps on settling — thus giving the appearance that the ocean is rising when, in fact, it’s the local land that’s sinking. The second source of complexity is caused by erosion of soil by wind and sea, which can gives the appearance that the ocean is rising, like on the Carolinas coastline.
Another significant factor is the movement of the Earth’s tectonic plates. The Earth’s crust floats on top of molten lava and is about eighteen miles thick. But the crust is not a solid piece. It’s made up of “plates,” which keep floating and moving around.
Earthquakes, volcanoes, and tsunamis also contribute to this continuing rearrangement of the land, and oceans respond and adjust accordingly.
Note: Portions of this article were excerpted from the 2020 book A Hitchhikers Journey Through Climate Change with permission of the author Terigi Ciccone. The book is the best possible source for parents and grandparents to explain reality to their children.