Thursday, January 21, 2010
Sir James Clark Ross
You probably haven't heard his name before. He was an explorer. He explored the Arctic on four voyages under Admiral Parry; and later led his own expeditions into the Antarctic.
Ross was employed on the magnetic survey of Great Britain. He was also tasked with discovering the magnetic south pole, and discovered/named many features and bays in Antarctica. Ross ice shelf and the Ross Sea are among things he first identified (later named for him).
Ross was a fanatic recorder, recording tidal, astronomical, and meteorological observations. He sailed to The Isle Of The Dead not far from Point Arthur (Tasmania)with the purpose of providing a benchmark. These are excerpts from his journal, made in 1841..
"The fixing of solid and well secured marks for the purpose of showing the mean sea level of the ocean at a given epoch was suggested by Baron von Humboldt..." (Another traveller, and hero of mine)....
"My principal object in visiting Port Arthur was to afford a comparison of our standard barometer with that which had been employed for several years by Mr. Lempriere, (the Deputy Commissary General) and also to establish a permanent mark at the zero point, or general mean sea level as determined by the tidal observations which Mr. Lempriere had conducted with perseverance and exactness for some time; by which means any secular variation in the relative level of the land and sea, which is known to occur on some coasts, MIGHT AT ANY FUTURE PERIOD BE DETECTED, AND ITS AMOUNT DETERMINED."
Ross gave Lempriere laborers and specific instructions to cut this mark in the exact spot which his tidal observations indicated as the mean sea level of the ocean.
July 1st 1841 the mean sea level mark was made. Careful present day observations put mean sea level, over a century and a half later, more than 4 inches below Ross's mark.
Thanks for the effort, Mr. Ross, but you wasted your time. Science ain't based on keen observation anymore. When your ice shelf seasonally recedes, it's due to our industrial greed. If you ask your average Joe, they'll insist the oceans have significantly risen in spite of the benchmark you provided.