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| Rising seas lap at a house in South America |
The research, funded by the National Science Foundation (NSF), was conducted by Andrew Kemp, Yale University; Benjamin Horton, University of Pennsylvania; Jeffrey Donnelly, Woods Hole Oceanographic Institution; Michael Mann, Pennsylvania State University; Martin Vermeer, Aalto University School of Engineering, Finland; and Stefan Rahmstorf, Potsdam Institute for Climate Impact Research, Germany.
"Having a detailed picture of rates of sea level change over the past two millennia provides an important context for understanding current and potential future changes," says Paul Cutler, program director in NSF's Division of Earth Sciences.
"It's especially valuable for anticipating the evolution of coastal systems," he says, "in which more than half the world's population now lives."
Adds Kemp, "Scenarios of future rise are dependent on understanding the response of sea level to climate changes. Accurate estimates of past sea-level variability provide a context for such projections."
Kemp and colleagues developed the first continuous sea-level reconstruction for the past 2,000 years, and compared variations in global temperature to changes in sea level over that time period.
The team found that sea level was relatively stable from 200 BC to 1,000 AD.
Then in the 11th century, sea level rose by about half a millimeter each year for 400 years, linked with a warm climate period known as the Medieval Climate Anomaly.
Then there was a second period of stable sea level during a cooler period called the Little Ice Age. It persisted until the late 19th century.
Since the late 19th century, sea level has risen by more than 2 millimeters per year on average, the steepest rate for more than 2,100 years.
"Sea-level rise is a potentially disastrous outcome of climate change," says Horton, "as rising temperatures melt land-based ice, and warm ocean waters."
To reconstruct sea level, the scientists used microfossils called foraminifera preserved in sediment cores extracted from coastal salt marshes in North Carolina. The age of the cores was estimated using radiocarbon dating and other techniques.
To test the validity of their approach, the team compared its reconstructions with tide-gauge measurements from North Carolina for the past 80 years, and global tide-gauge records for the past 300 years.
A second reconstruction from Massachusetts confirmed their findings.
The records were corrected for contributions to sea-level rise made by vertical land movements.
The reconstructed changes in sea level over the past millennium are consistent with past global temperatures, the researchers say, and can be determined using a model relating the rate of sea level rise to global temperature.
"Data from the past helped calibrate our model, and will improve sea level rise projections under scenarios of future temperature increases," says Rahmstorf.
Support for the research also was provided by the National Oceanic and Atmospheric Administration, United States Geological Survey, the Academy of Finland, the European Science Foundation through European Cooperation in Science and Technology and the University of Pennsylvania.
ScienceDaily (June 20, 2011) — The rate of sea level rise along the U.S. Atlantic coast is greater now than at any time in the past 2,000 years -- and has shown a consistent link between changes in global mean surface temperature and sea level.
So Sea Level is rising again! This time, by more than 2mm per year! And all these are linked to Global warming, our climate is getting hotter and hotter, the ozone layer is depleting, the world's sea levels are rising drastically and drowning islands, our world is getting dirtier, weaker and warmer. And nobody is doing anything to save it, just quite ignorant of the fact that by dumping one peice of rubbish doesn't really making a difference on the world's climate and ecosystem. But imagine a entire city of million doing the exact same thing and h ow it is going to hurt our ecosystems. Rising temperatures melt land-based ice, and warm ocean waters, these water from the ice eventually flows into bigger oceans lie the Atlantic and Pacific. When the ocean waters warm, fishes cant survive, coral reefs get bleached and die. A warm sea has greater volume than a cold sea and when the sea is heated it will increase in volume, leading to changes in sea level (thermal expansion). The oceans are large and are enormous energy stores. They are heated slowly and retain the heat for a long time, long after the heating has ceased. It takes years to transport heat down to the ocean depths. Even if we stop emitting greenhouse gases today, the sea will get warmer and warmer, and rise for the next 20 years. Plankton will also not be able to survive in these warm waters and many animals in the water will migrate in search of colder areas. This is a serious cause for concern but many people are still not aware of it or they are just acting ignorant of teh fact that they, themselves will be the ones paying for their mistakes. When the ocean floods towns and drowns people, and the Sun's UV Rays shine through and more people die from skin cancer, droughts occur, only then will the uncaring people regret what they've done over the past few decades. When people cut down trees, they may say that it is essential to cut trees for paper, if not, there would not be enough paper in the industry. These paper companies have never thought of any initiatives to save these trees, these trees just give them money, and money is what they want. Everyone, including you and me will have the mentality when we litter that, our one piece of litter doesn't affect our climate at all, but imagine the difference when 10000 people in the world litter at the same time. Our Earth may be able to tolerate 100 peices of litter, but will it be able to tolerate 10000 peices of litter at the same time? We may think that we are not going to be the ones affected because there is still a long time before Sea Levels start to flood islands and the Ozone Rays get depleted, but that is a seemingly irresponsible and selfish thought. Haven't we always wanted the best for our children and further generations? If these were what we wanted to give them, i would like to say that mankind has failed itself. Without doubt, i could point everyone who is hurting the environment in his own way. Be it, logging, littering, not recycling, reusing or reducing or dumping rubbish at landfills, everyone is an environment destroyer. The world we live in just gets hotter and hotter, for example, Singapore's temperatures have been rising drastically, over the past few years and i have reasonable evidence that many singaporenas like you and me are feeling the heat. We may be able to stant the heat now and until we die, but will our children be able to stand the climate conditions when the temperateure goes over 40 degrees? The climate changes, storms erupt more frequently, resulting in severe flooding, during very warm weather, droughts starts, islands get flooded by the sealevel and in the worst case scenario- Many people die from heatstroke. Earthquakes, Tsunamis, Tornados become even more common. During that time, every country an every island will be affected by some form of natural disaster, and no country will be spared! Even then, we may be already lying in our own graves an watching the inferno outside, but think, if the disasters were all whecked on our children and us responsible for it, think of the pain they will suffer. Why not just make our Universe a better place for everyone? So if we do not start now, and continue our ignorant, irresponsible and uncaring mentalities and ways, never will we be able to save our universe, it will just forever remain as a broken promise. A broken promise made by the 21 century people to save the universe. But they never did. Start now! Cut down on logging, reduce emmissions, reduce, reuse and recycle! And most importantly, dump your car and never drive it again. As i end my long reflection here, i want to urge everyone to be mindful of the state of their Earth and not be ignorant, irresponsible about their future. The future of everyone belongs and depends on us, it is up to us to make the right decisions! Below is an interesting video about the Rising Seas.
Hoped you liked that video which mentioned many important information about the warming of ocean and the rising of sea levels, including the melting of Glaciers and the Antartic Ice Sheets.
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