Past Global Warming Shows Us What the Future Holds
Past global warming triggered massive sea level rise, and the future might bring this back again. The period of global warming which occurred at the end of the last ice age did not indicate a steady sea level rise. Apparently, the sea levels rose in sharp bursts due to the meltdown of glaciers. Researchers indicate that they have discovered evidence of fossils.
They have analyzed fossils from drowned reefs offshore Texas. These reefs indicated sea level increased in bursts, where the length varied from a few decades to a century. Andre Droxler is a marine geologist from Rice University, and he is also the coauthor of the new study. Droxler indicates that the fossil reefs they have analyzed indicate that the last time climate change was as severe as today, sea levels did not rise steadily.
The study proves that sea levels increased very fast and then paused for a while just to start right back again in another burst. Droxler highlights the fact that this discovery will play an important role in the future study regarding sea-level rise. In the past, scientists did not have specific evidence regarding the punctuated “decade-scale sea-level rise”. Hence, they had to present the sea-level rise risks in a linear format.
Past global warming determined changes in sea levels
For instance, the International Panel on Climate Change only took the projected rise for a century and then they divided it by 100. As a result, they stated how much they expect sea levels to rise every year. The International Panel on Climate Change is an authoritative scientific source which provides data about the effects of human-made climate change. Despite this, the way they developed the measurements does not seem very accurate.
Jeff Nittrouer is a coastal geologist and also the coauthor of the new study. He argues that their results provide clear evidence regarding sea level rise. The evidence of this new research appeared after researchers at the Schmidt Ocean Institute conducted a cruise. During their cruise, they used the vessel Falkor’s multibeam echo sounder.
In this way, they were able to identify ten fossil reef sited located offshore Texas. The eco sounder is a very advanced tool which generates high-resolution 3D images of the seafloor. Hence, scientists revealed the fossil reefs lying 30-50 miles offshore Corpus Christi. They were located at 195 feet deep under water.
Sunrise is unable to reach that depth. However, due to the fact that corals live in symbiosis with algae, they would need natural light to grow. Relying on other studies about the Texas coastline that refer to the last ice age, the team managed to obtain these results. Furthermore, they have also relied on the dates of fossil samples collected from those reefs in past expeditions.
Scientists are used to see a steadily sea level rise
Researchers estimated that the reefs started developing about 19,000 years ago. Back then, glaciers and melting ice caps determined a worldwide sea level rise. Khanna indicates that the demise and evolution of coral reefs were not affected. The history of these reefs is deep in their morphology. Furthermore, the high-resolution 3D imagining system on the vessel Falkor helps researchers analyze the forms of the reefs in detail.
All the reefs featured terraces. Specialists indicate that this type of structures is specific for coral reef structures. What is more, these terraces are the perfect indicator of rising levels of the seas. For instance, when a reef is growing towards the surface of a sea, it can develop very fast. Hence, if sea levels rise rapidly, then the water will drown the reef in place.
However, in case the rate of sea level rise is slower, the reef will adopt the strategy known as backstepping. This means that the side of the reef that faces the ocean breaks up the waves enough to permit the reef to develop a vertical step. Khanna explains that the steps of this terraces indicate how the reef was able to adapt to a sudden change in sea levels.
The terraces situated behind each step represent the parts of the reef that could continue their development. Hence, they filled while the bursts of the sea level rise seized. Researchers discovered some sites where corals had six terraces. Even if the sites they have analyzed are at 75 miles apart one from the other, the depth of these terraces appeared to line up.
The sea level rise occurred in bursts
Khanna spent over a year to analyze the data from the mapping mission. Droxler claims that their study is the first that offers evidence regarding the sea level rise, showing the fluctuations on a scale ranging from decades to a century. Many other scientists suspected that sea level rise cannot be steady all the time. Now, the new study supports their ideas, bringing evidence in favor of their statements.
They have specifically indicated that the levels may not rise linearly. This new research intends to raise awareness regarding the impact of sea level rise on communities living by the sea. They will need to prepare for future inundations in case similar sea level bursts will occur.
This unusual type of sea level rise jeopardizes the well-being of several areas across the globe where half billion people live within a few meters from the sea. They might experience future inundation if glaciers and ice shelves in the Arctic continue to melt. The rise of temperatures triggered a massive meltdown in Antarctica where the ice layers become thinner and thinner.
Nittrouer indicates that they have noticed sea level rise steadily “in contemporary time”. Nevertheless, their new study indicates that the sea level could rise even faster than they can predict. Due to this situation, coastal communities should prepare for potential inundation.
The study brings incredible evidence from sites and areas which experienced past global warming events. However, specialists claim that there may appear sudden changes in sea levels in case a large amount of ice may be released into the ocean. Therefore, it is best if we prepare for what is worst. Researchers try to raise awareness especially among communities living by the sea.
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