Those who argue human greenhouse gas emissions are causing dangerous climate change regularly point to rising seas as one of the most certain and devastating impacts on human communities.
According to environmental activists, mainstream media outlets and some scientists—who routinely cite Intergovernmental Panel on Climate Change (IPCC) reports—unless governments take drastic action to transform the world’s economic system, including ending the use of fossil fuels for energy in a very short period, entire island nations will disappear beneath the seas and low-lying coastal cities will be swamped, forcing a great migration of populations inland.
The threat of rising seas to various communities is not, in the words of the immortal Shakespeare, “Much Ado About Nothing.” However, alarming claims made about humanity’s contribution to rising seas by government bureaucrats, environmental lobbyists and scientists with a vested interest in imposing their socialist vision of society on a largely unwilling public are, also in the words of Shakespeare, “tale[s] told by … idiot[s], full of sound and fury, signifying nothing.”
The IPCC asserts it is “very likely” sea level rise has accelerated since the middle of the twentieth century in response to warming caused by rising greenhouse gas emissions, and “it is very likely that the rate of global mean sea level rise during the 21st century will exceed the rate observed during 1971–2010 … due to increases in ocean warming and loss of mass from glaciers and ice sheets.”
However, hard data show, contrary to IPCC claims, ocean levels are not rising at either an unusually rapid rate on average globally, nor by an abnormal amount in historical terms.
A new report by Drs. Craig Idso, David Legates, and S. Fred Singer, released by The Heartland Institute, proves this point beyond any doubt. The scientists examined long-term data from tidal gauges and other sources and concluded the amount of sea-level increase Earth has experienced over the past century is not unusual historically, nor has the rate of rise increased significantly over the past few decades. As Idso, Legates, and Singer put it, “the highest quality coastal tide gauges from around the world show no evidence of acceleration since the 1920s.”
The disconnect between data recorded by the global tidal gauge system and projections made by IPCC is due, according to the authors, to the fact that “[l]ike ice melting, sea-level rise is a research area that has recently come to be dominated by computer models. Whereas researchers working with datasets built from long-term coastal tide gauges typically report a slow linear rate of sea-level rise, computer modelers assume a significant anthropogenic forcing and tune their models to find or predict an acceleration of the rate of rise.”
A 2017 report released by The Heartland Institute, authored by geophysicist Dennis Hedke, analyzed data collected from 10 coastal cities with relatively long and reliable sea-level records, including Ceuta, Spain; Honolulu, Hawaii; Atlantic City, New Jersey; Sitka, Alaska; Port Isabel, Texas; St. Petersburg, Florida; Fernandina Beach, Florida; Mumbai/Bombay, India; Sydney, Australia; and Slipshavn, Denmark. Hedke found there was no correlation between changes in sea levels at these locations and rising carbon dioxide levels.
For some cities, the rate of sea level rise has remained virtually constant, neither increasing nor declining appreciably from the rates experienced before humans began adding substantial amounts of greenhouse gases to the atmosphere. By contrast, some cities, such as Ceuta, Spain, have experienced very little sea-level rise over the past century, exhibiting almost a flat trend line, below the historic rate of global sea level rise of approximately seven inches per century. Other cities, such as Sitka, Alaska have actually experienced falling sea levels. Still other cities, such as Atlantic City, have experienced a large, rapid increase in sea levels.
The point is that different areas around the world are having different experiences with sea levels, none of which correspond well either with the projections made by IPCC based on computer models or the steady increase in atmospheric greenhouse gas concentrations. Rather than responding to rising greenhouse gas levels, changes in sea levels seem to reflect localized conditions.
Although, on average, global sea levels have risen by approximately 400 feet since the beginning of the end of the most recent ice age—approximately 20,000 years ago—the rate of sea level rise has risen and fallen at various times, slowing and increasing on the order of tens, hundreds, and thousands of years over the past 20,000 years, having nothing whatsoever to do with human activities.
Human activities, such as the construction of barriers, the channelization of rivers, installing pumps, the conversion of coastal wetlands to densely populated metropolitan areas, filling in shallow water bays, replenishing eroded beaches and the draining of coastal aquifers for human consumption have undoubtedly contributed to making some coastal regions and populations more vulnerable to rising seas and other cities and populations less vulnerable. However, when analyzing the causes and consequences of changing sea levels, there is little evidence increased greenhouse gas emissions are contributing to higher ocean levels.
Our knowledge of previous interglacial cycles indicates seas are going to continue rising unless and until the next ice age comes, notwithstanding any efforts humanity makes to stem the rising tides; like the efforts of the apocryphal story of King Canute, they are bound to fail.
It makes sense to prepare for rising seas by hardening coastal areas, discouraging poorly designed coastal development, and making people living along coasts aware it is hazardous and investments made there could be swallowed by rising water. However, ending the use of fossil fuels, and giving ever larger government increasing power over peoples’ lives will not stop seas from rising, but instead will only serve to make the world’s people poorer and less free.