Sunday, 11 December 2011

Sea Levels are Rising

I had a discussion on rising sea levels this afternoon and I was given a link to a article by an accredited scientist based on actual observations (http://tinyurl.com/yztgfap).  This sounds promising I thought, he appears well placed to comment on this topic, lots of experience and involvement with the sea level commision of an international resaerch union, the International Union for Quaternary Research (INQUA).

Dr. Nils-Axel Mörner is the head of the Paleogeophysics and Geodynamics department at Stockholm University in Sweden. He is past president (1999-2003) of the INQUA Commission on Sea Level Changes and Coastal Evolution, and leader of the Maldives Sea Level Project. Dr. Mörner has been studying the sea level and its effects on coastal areas for some 35 years.

But all is not as it seems.  Despite the INQUA credentials quoted, INQUA do not agree with Mörner's findings, in fact they tend to agree that sea levels are rising, from their web page:




Quaternary Science (By S.C. Porter)
The Quaternary Period spans approximately the last two million years of the Earth's history, an interval dominated by frequent changes in global climate that led to a succession of glacial and interglacial ages. Quaternary scientists study the complex environmental changes of the glacial ages and interpret them using analogies to present-day processes and environments. A major goal of these investigations is to document the pattern and timing of climatic changes in order to understand the causes of changing climate on various time scales. Such investigations are of prime importance: the Earth, influenced by human activities, is entering a time of unusually warm climate in which significant and potentially rapid environmental changes could pose major challenges for human habitability.
Average Northern Hemisphere temperature trend (- 20-year filter; -- 100-year filter) during the past 350 years, showing a pronounced 20th-century warming.
Average Northern Hemisphere temperature trend (- 20-year filter; -- 100-year filter) during the past 350 years, showing a pronounced 20th-century warming.
Because the study of environmental change is a strongly interdisciplinary one, Quaternary research involves a broad range of specialists in such fields as anthropology, climatology, geochronology, geography, geology, glaciology, isotope geochemistry, palaeocean-ography, palaeoecology, palaeontology, palynology, and soil science. Working collaboratively, Quaternary scientists bring their training and experience to bear in interpreting the changing world of the glacial ages, and their impact on our planet's surface environments, as well as their possible role in the human evolution. Quaternary palaeoclimatic investigations play a key role in helping evaluate the possible future course of climate change on our planet.
Role of Quaternary paleoenvironmental studies in assessing past and future climate. Variations in past climate, in both time and space, are reconstructed from varied geologic, isotopic, and paleontological evidence, thereby permitting causal factors and past surface environments to be determined. These data provide input to computer models used to test hypotheses about past and future climates.
Role of Quaternary paleoenvironmental studies in assessing past and future climate. Variations in past climate, in both time and space, are reconstructed from varied geologic, isotopic, and paleontological evidence, thereby permitting causal factors and past surface environments to be determined. These data provide input to computer models used to test hypotheses about past and future climates.

 

Reading the tone of the original article does give the impression that Mörner genuinely believes that he is right and that everyone else is wrong but the evidence he presents is weak at best.  Such an article may not be the forum to produce actual measurements but a graph or table of typical (or even selected) results to show how he has drawn his conclusion would be useful.  The only real evidence discussed is the presence of a tree which has not been washed away as it would have been if sea levels were rising.  Nice anecdote but hardly science.

I recently read another article which looked at sea level rises along England's south coast which presented some real data, i.e. tide gauge readings, over the period from 1900 in some cases.  
Figure from Haigh, Nicholls and Wells, Rising sea levels in the English Channel1900 to 2100,Proceedings of the ICE - Maritime Engineering, Volume 164, Issue 2, 01 June 2011 , pages 81 –92 , ISSN: 1741-7597, E-ISSN: 1751-7737

This very real data shows a distinctive trend along the length of the English Channel. Admittedly it is only one very small part of the world but it is definitely more convincing than a tree on the beach. One argument against this data is the fact that the south of England is settling geologically, part of the same isostatic rebound phenomenum that is causing the north of Scotland to rise. This has been included in the table below giving a net sea rise of about 1.4mm/year or 140mm per century.




There have been many other studies undertaken around the world which show similar trends so there is either a huge international conspiracy or Dr Mörner is mistaken in his conclusions.

A more thorough critique of Dr Mörner was presented by George Monbiot in the Guardian but I like to do a bit of my own research rather than thoughtlessly agreeing with him. And another critique from skeptical science.

Sea levels have risen over the past century and will rise over the next. The magnitude and rate of the future rise depends on how much higher the concentration of carbon dioxide in the atmosphere increases. 

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