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.
Most recently, Fox News hyped a study out of the National Oceanic and Atmospheric Administration (NOAA) claiming, “Communities in coastal areas of the U.S. saw record-setting high-tide flooding last year, part of a trend of rising seas … [and an] ‘extraordinary’ rise in high-tide flooding since 2000.”
“Damaging floods that decades ago happened only during a storm now happen more regularly, even without severe weather,” Nicole LeBoeuf, acting assistant administrator for NOAA’s National Ocean Service, told reporters in a conference call.
The problem with Fox News’ coverage (and the claim itself) is that there is nothing extraordinary about the sea level rise over the past century. In areas where flooding has increased in frequency in recent years, climate change is not responsible.
As detailed in Climate at a Glance: Sea Level Rise, data show global sea level has been rising at a relatively steady pace of approximately one foot per century since at least the mid-1800s. Moreover, the Intergovernmental Panel on Climate Change reports no significant recent acceleration.
Global sea levels have risen on average by approximately 400 feet since the beginning of the end of the most recent ice age—approximately 20,000 years ago—with the rate of sea level rise having increased and decreased at various intervals. This has nothing whatsoever to do with human activities.
Indeed, as NASA reports, sea levels always rise during interglacial periods as ice sheets retreat. During the last interglacial period, seas were four to six meters higher than today. The best evidence is, regardless of what humans do, sea levels will continue to rise, although not uniformly, until the next ice age begins. NASA’s records indicate the current rate of sea level rise is much slower than the average for most of the interglacial period. In fact, there have been periods during the current interglacial period when seas rose by as much as 10 to 15 meters in less than 500 years.
Nor are seas rising consistently throughout the globe. As detailed in a report by the Nongovernmental International Panel on Climate Change (NIPCC), some cities, like Ceuta, Spain have experienced almost no sea level rise over the past century. Other cities, such as Sitka, Alaska have actually experienced declining sea levels. Still other cities, such as Atlantic City, New Jersey have experienced a large, rapid increase in sea levels.
Although human activities are likely contributing to “high-tide” flooding on sunny days, the activities in question are not the emission of greenhouse gases from energy use. Rather, activities such as the construction of barriers and impervious surfaces leading to increased runoff, the channelization of rivers, 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 are most responsible. These land use changes have undoubtedly contributed to making some coastal regions and populations more vulnerable to rising seas and other cities and populations less vulnerable.
For instance, the Chesapeake Bay region along the East Coast is one of the regions NOAA discusses as experiencing increased high-tide flooding in recent years. However, a second NIPCC report shows “water intrusion problems in the Chesapeake Bay region are due not to sea-level rise, but primarily to land subsidence due to groundwater depletion and glacial isostatic adjustment.”
It makes sense to prepare for rising seas by hardening coastal areas, discouraging poorly designed coastal development, and making people living along coasts aware that it is hazardous and investments made there could be swallowed by rising water. However, our knowledge of previous interglacial cycles indicates seas are going to continue rising unless and until the next ice age comes, notwithstanding any actions we take to stem the rising tides. Like the efforts of the apocryphal story of King Canute, they are bound to fail.
It is sad so many people have been hoodwinked by the climate change-flood connection hyped by holdovers from previous presidential administrations at NOAA, who, ever clamoring for more funding, erroneously imply that human climate change is causing increased coastal flooding and rising sea levels. In reality, climate change has little to nothing to do with rising and declining sea levels.
H. Sterling Burnett, Ph.D. ([email protected]) is a senior fellow on energy and the environment at The Heartland Institute, a nonpartisan, nonprofit research center headquartered in Arlington Heights, Illinois.