At 2:30 p.m. February 2, 2013, seven bricks were exposed beneath the fort entrance. These bricks appeared dry and this gave reason to believe the observation was made at high tide. Checking tide data for the Dry Tortugas confirmed 2:20 p.m. was high tide for February 2, 2013.
Checking books in the Fort Jefferson bookstore produced a picture of the fort entrance taken in January 1937. This picture showed all dry bricks above the water line and indicated about 7 and 3/4 bricks were above the water line. A brick and one layer of mortar has a height of about 85 mm and it was estimated the change in Gulf of Mexico water level for the 75-year period was 75 mm. This indicates an annual change in water level at Fort Jefferson of 1 mm per year.
It may be argued the 1937 picture was not been taken at high tide. If this is true, then the change in sea level would have been less than 1 mm per year. It may be argued the fort is sinking due to its extreme weight. If this is occurring, the sea level rise would be smaller than 1 mm per year.
The National Oceanographic and Atmospheric Association (NOAA) has a map of the world showing sea level changes at hundreds of locations around the world.
The closet NOAA sea level change data near Fort Jefferson is for Key West, Florida and Cabo San Antonio, Cuba. Both locations are about 70 miles from Fort Jefferson. For the period 1913-2012, Key West has a sea level rise of 2.24 mm per year. For the period 1971-2009, Cabo San Antonio has a sea level rise of 3.30 mm per year.
Sea level rises in both locations reported by NOAA data are considerably greater than rough measurements made at Fort Jefferson. It is left for NOAA to explain this discrepancy on sea level rise for locations so close to each other.
While staying in Fort Lauderdale, I observed an Egret traversing a complicated parking lot in a shopping mall. The Egret wanted to cross a traffic circle and watched car traffic and waited until there was a break in the traffic. The Egret apparently understood by observation, cars were not going to give the right-of-way to birds. Birds posed no threat to these enormous cars. The Egret successfully maneuvered to the other side of the traffic circle.
This observation counters complaints of global warming alarmists that increasing global temperatures will cause extinction of the earth’s species because they don’t allow for adaptation. Species adapt to change as shown by experience over billions of years.
Climate alarmists don’t allow for adaptation. They think the human species is incapable of deducing you could open an umbrella to shield oneself from rainfall. If you carry umbrellas; it functions the same as sticks.
Climate change is inevitable by definition. It is arrogant for humans to believe they can change nature. Skeptics observe their surroundings and make judgments based on these observations. Unfortunately, climate alarmists insist on placing bags over their heads so they fail to make observations contrary to their beliefs. Skeptics should continually observe their surroundings and report events that support no big catastrophes for the planet.