Environmental activists, mainstream media outlets, and many scientists routinely claim governments must take drastic action to transform the world’s economic system, including ending the use of fossil fuels, or island nations will disappear beneath the seas and low-lying coastal cities will be swamped, forcing a great migration of populations inland.
To back up their claims, they cite statements from the Intergovernmental Panel on Climate Change (IPCC) asserting 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. The IPCC, however, bases its claim on computer model projections instead of measured, real-life data.
Data lend little support to the claim seas are rising at a historically unusual or increasingly rapid rate. 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), with the sea level rise slowing and increasing over periods of tens, hundreds, and thousands of years over the past 20,000 years, having nothing whatsoever to do with human activities.
Research shows most of the islands making up nations such as Tuvalu and the Maldives are gaining land and mass, not losing it. A peer-reviewed study that examined 600 coral reef islands in the Pacific and Indian Oceans reported approximately 40 percent of those islands remained stable and 40 percent grew. More evidence they and coastal areas in Florida and Hawaii, for instance, aren’t sinking beneath the waves can be inferred from the fact that the populations on these island nations and the coastal United States are increasing instead of fleeing, and they are putting up new, expensive buildings and associated infrastructure daily.
A 2019 report by Drs. Craig Idso, David Legates, and the late S. Fred Singer confirms sea levels have not been rising at an unusual rate in recent years. After examining long-term data from tidal gauges and other sources, Idso, Legates, and Singer write, "the highest quality coastal tide gauges from around the world show no evidence of acceleration since the 1920s."
The difference between data recorded by the global tidal gauge system and projections made by various purported climate authorities is because "[l]ike ice melting, sea-level rise is a research area that has recently come to be dominated by computer models," the authors write. "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."
Human actions, such as the construction of barriers, channeling of rivers, conversion of coastal wetlands into densely populated metropolitan areas, and draining of coastal aquifers for human consumption (which causes land subsidence) have undoubtedly made some coastal regions and populations more vulnerable to rising seas. Nonetheless, there is little evidence increased greenhouse gas emissions are contributing to ocean rise.
In a 2017 Heartland Institute study, geophysicist Dennis Hedke analyzed data from 10 coastal cities with relatively long and reliable sea-level records and 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. Other cities, such as Ceuta, Spain, have experienced very little sea level rise over the past century, exhibiting almost a flat trend line well below the historic rate of global sea level rise of approximately seven inches per century. Other cities, such as Sitka, Alaska, have experienced falling sea levels. Still others, such as Atlantic City, New Jersey, have experienced a large, rapid increase in sea levels.
The point is different areas around the world are having different experiences with sea levels, with differences in the rate of sea level rise being a result of localized conditions, not global climate change.
Some alarmists have recently tried to respond to observation that claims of accelerating rates of sea level rise are based on computer models alone, not hard data, by citing satellite-reported sea-level data collected by University of Colorado researchers. Their dataset indicates seas are rising by approximately 3.3 mm per year, much higher than the annual rise of approximately one to two mm recorded at tidal stations, a rate that has changed little over the century or so for which we have adequate records.
The rate of rise claimed by the University of Colorado researchers is a result of statistical sleight of hand, produced by mixing data from four different satellites: combining data from two earlier satellites and two later satellites that record significantly higher rates of sea-level rise than the earlier two satellites. As meteorologist Anthony Watts points out, the earlier dataset shows a much smaller trend of sea level rise than the latter two satellites:
Neither set of the satellite record shows any accelerating trend. The UC scientists simply combined the two dissimilar data sets, plotted a new trend showing acceleration, and didn’t mention the difference.
This is either incompetent or dishonest, and certainly not up to even the simplest of basic science principles. Virtually any high school or college student who presented such work for a class would get called out on it by their instructor for showing a false trend.
Our knowledge of previous interglacial cycles indicates seas will continue rising unless and until the next ice age comes, notwithstanding any efforts humanity may make to stem the tides.
It makes sense to prepare for rising seas by hardening coastal areas, discouraging ill-advised coastal development, and making people living along coasts aware investments made there could be swallowed by rising water. Ending the use of fossil fuels and giving ever-larger governments increasing power over peoples’ lives will not stop the seas from rising and will only make people poorer and less free.
SOURCES: The Heartland Institute; Intergovernmental Panel on Climate Change; The Heartland Institute; Climate Realism; Climate Realism
Dr H. Sterling Burnett is a Heartland senior fellow on environmental policy and the managing editor of Environment & Climate News.