Proponents of climate change are adamant about allegiance to their rules in case nature strikes the Earth with a mighty blow. This is the reason believers, for instance, who are true followers like Barack Obama only purchase property which is secure against rising sea levels… or not…
Yet, defenders the faith are not stopping their fight, claiming you should believe them or your skewed ears and eyes. Recent efforts include photos recently published of Sydney Harbor taken 140 years apart from each other.
Let the outrage commence, thanks to Reuters:
“It is not possible to gauge sea level rise simply by comparing two images of a location side-by-side, experts told Reuters, despite claims made online.”
“The photographs may reflect ‘different tidal stages,’ Gary Griggs, Distinguished Professor of Earth and Planetary Sciences, University of California, Santa Cruz, told Reuters.”
“An absolute global rate of sea-level rise has been recorded since 1993 by orbiting satellites, Prof Griggs said.”
“This rate has averaged 3.42 mm/yr. but over the past decade or so has increased to 4.77mm/yr. over the past 10 years,” he claimed.
This raises the issue of how sea levels can be determined by satellite. Hanging a massive dipstick from a satellite to the ocean is likely to prove difficult. The actual process is explained below:
Satellite altimetry is all about timing. Sea-surface height can be measured by the time it takes for radar pulses to hit the ocean surface and bounce back to the spacecraft. Laser altimetry works in a similar manner, as laser pulses bounce off land-ice and sea-ice surfaces. But this method requires precise knowledge of satellite altitude, as well as the terrestrial reference frame (see question on how NASA studies sea level change). Extensive calibration is necessary to ensure the accuracy of altimetry measurements.
Therefore, we're counting on NASA to know exactly how high their satellites are flying to monitor the level of oceans.
As you've probably observed when pouring water into a container, the water level increases evenly regardless of whether the surface of the container is uneven. It is evident that oceans have more complex surfaces than the typical terrarium. There are many other variables at play including volcanoes and earthquakes that change the levels of the sea floor. But even with these variables, one would expect that the sea level will remain relatively constant over time, either rising, dropping, or remaining as it is now. According to an image on NASA's website, it has been completely inconsistent over the past twenty years. This makes one think.
It also raises the question of where the pesky sign of rising oceans could be. Are islands or port side cities being flooded or harbors expanding? No, but we should still believe the experts!
“Local rates, whether Sydney or San Diego, provide sea level changes relative to land. Where the land is rising or sinking will produce different local rates. So, in Sydney, the land has been rising over the period of tide gauge measurements producing lower than global sea level rise rates,” he (Gary Griggs, Distinguished Professor of Earth and Planetary Sciences, University of California, Santa Cruz) added.
How convenient. Let's celebrate how it will be still there in the future.