Sea level rise: Climate change and an ocean of natural variability

Sea level rise: Climate change and an ocean of natural variability
September 19, 2013

Steve Goreham

Steve Goreham, a policy advisor to The Heartland Institute, is a speaker, author, and researcher on... (read full bio)

Sea level rise is the greatest disaster predicted by Climatism, the belief  in catastrophic climate change. Today, leading scientific organizations support  the idea that the ocean level is rising due to man-made emissions. Further, they  claim to be able to measure ocean level to a high degree of accuracy. But a look  at natural ocean variation shows that official sea level measurements are  nonsense.

The theory of man-made climate change warns that human emissions of  greenhouse gases will raise global temperatures and melt Earth’s icecaps,  causing rising oceans and flooding coastal cities. Former Vice President Al  Gore’s best-selling book, An Inconvenient Truth, showed  simulated pictures of flooding in South Florida, the Netherlands, Bangladesh,  and other world locations. Dr. James Hansen predicted an ocean rise of 75 feet during the  next 100 years.

The Intergovernmental Panel on Climate Change stated in 2007, “Global average sea level  rose at an average rate of 1.8 mm per year over 1961 to 2003. The rate was  faster over 1993 to 2003: about 3.1 mm per year.” This translates to a 100-year  rise of only 7 inches and 12 inches, far below the dire predictions of the  climate alarmists.

But three millimeters is about the thickness of two dimes. Can scientists  really measure a change in sea level over the course of a year, averaged across  the world, which is two dimes thick?

Today, sea level is measured with satellite radar altimeters. Satellites bounce radar waves off the surface of the ocean to measure  the distance. Scientific organizations, such as the Sea Level Research Group at  the University of Colorado (CU), use the satellite data to estimate ocean rise.  The CU team estimates current ocean rise at 3.2 millimeters per year.

The organizations AVISO (Archiving, Validation, and  Interpretation of Satellite Oceanographic Data) of France, CSIRO (Commonwealth Scientific and Industrial  Research Organization) of Australia, and NOAA (National Oceanic and Atmospheric  Administration) of the United States agree with the University of Colorado that  seas are rising three millimeters per year. Given the huge natural variation in  global sea level, the three millimeter number is incredible. The fact that four  different organizations have arrived at the same number is suspect.


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As Dr. Willie Soon of Harvard shows, ocean level variation is large and  affected by many factors. If temperatures rise, water expands, adding to sea  level rise. If icecaps melt, levels rise, but if icecaps grow due to increased  snowfall, levels fall. If ocean saltiness changes, the water volume will also  change.

The land itself moves continuously. Some shorelines are rising and some are  subsiding. The land around Hudson Bay in Canada is rising, freed of ice from the last ice age.  In contrast, the area around New Orleans is sinking. Long-term movement of  Earth’s tectonic plates also changes sea level.

Tides are a major source of ocean variation, primarily caused by the  gravitational pull of the moon, the sun, and the rotation of the Earth. Ocean  water “sloshes” from shore to shore, with tides changing as much as 38 feet per day at the  Bay of Fundy in Nova Scotia. The global average tide range is about one meter,  but this daily change is still 300 times the three-millimeter change that  scientists claim to be able to measure over an entire year.

Storms and weather are major factors affecting satellite measurements. Wave  heights change by meters each day, dwarfing the annual rise in ocean level.  Winds also change the height of the sea. The easterly wind of a strong La Niña  pushes seas at Singapore to a meter higher than in the eastern Pacific  Ocean.

Satellites themselves have error bias. Satellite specifications claim a  measurement accuracy of about one or two centimeters. How can scientists  then measure an annual change of three millimeters, which is almost ten times  smaller than the error in daily measurements? Measuring tools typically must  have accuracy ten times better than the quantity to be measured, not ten times  worse. Dr. Carl Wunsch of the Massachusetts Institute of Technology commented on the satellite data in 2007, “It  remains possible that the database is insufficient to compute mean sea level  trends with the accuracy necessary to discuss the impact of global warming—as  disappointing as this conclusion may be.”

Scientists add many “fudge factors” to the raw data. The same measurement  taken by each of the three satellites, TOPEX, JASON-1, and JASON-2, differs by 75 millimeters and must be  corrected. As a natural adjustment, researchers add 0.3 millimeters to the measured data,  because ocean basins appear to be getting larger, able to hold more water, and  reducing apparent ocean levels.

Tide gauges are also used to “calibrate” the satellite data. But gauge  measurements are subject to errors of one or two centimeters, again many  times more than the sea level rise to be measured.

Clearly, the official three millimeter sea level rise number is a product of  scientific “group think.” Not only is this number far below what can be  accurately measured, but all leading organizations support this nonsense number.  Could it be that our leading scientists must endorse sea-level rise to support  the ideology of man-made global warming?

Steve Goreham

Steve Goreham, a policy advisor to The Heartland Institute, is a speaker, author, and researcher on... (read full bio)