Of them out on sponsors bury the biggest mobile sponsor vary in the world. The system ultimately starts because if the water comes up more than 3 meters im able to go to where people are going to be a part of me there she gonna be. Among the water because opec is 5 meters of water. In recent years the global Sea Level Rise has been accelerating this marks the beginning of a trend that could dramatically change much of the landscape spines. Maybe those of c. That was what does the worst Case Scenario look like. That is the. Its a starting condition and if they get it wrong the cost could be a mans loss is. Just too close to cities. How much time do we have left to find a solution has to be there will be places we wont be able to say if you can how can we protect ourselves against this rising danger. Not engineer ill sail out of sea look at how. Close it is a prominent physicist who studies the risks associated with rising sea levels his research could help prevent billions of dollars worth of damage in new york city one of the welds most vulnerable cities. Around the year 2 cells. Some scientists here in new york got together and we realized that we have to really raise the Public Awareness of the risks that are coming our way. We chose a 100 year storm coming into the city on the computer it was a model any help the 1st results that they called us and said you have a problem look at this what they got. They said oops. This is hes a killer heel is that its main artery silicate it underground and. We found out through a surprise that it takes only about 40 minutes for the. Subway system to fly. For a decade the simulation devised by klaus iacob and his colleagues remains little more than scientific speculation. 2012 Hurricane Sandy showed that the apocalyptic scenario modeled by the scientists was uncomfortably close to reality. Take a look at the water actually just in new york city sandy killed 44 people 100000 homes were flooded and millions of residents were left without electricity for weeks the damage to the city was estimated at 19000000000. 00 the city was up to its neck in water. Until recently such extreme weather was regarded as a once in a century of event but that has changed. Klaus iacob believes that even a slight rise in sea levels could trigger a significant rise in flooding. Supply yourself for this much is 9 feet 3 me those of your eyes by the end of the century and then 63 news. Around the World Population growth and urbanization in coastal regions is outstripping demographic developments further inland yet coastal populations are far more vulnerable to the impact of rising sea levels there are 136 coastal cities with people. The population of those cities was about 400000000 people but about 14000000 of those people actually live in the coastal flood playing with current see the balls. In many places coastlines have been fairly stable and coastal flooding largely limited to storm surges which are around the. Extreme water levels a recurring with growing frequency scientists believe this is the 1st phase in our long term process which is also gaining momentum. To go off to tom and then lets see what weve seen along germanys coast over the last few decades is that extreme water levels have been rising more quickly than the Mean Sea Level. Scientists are investigating what rising sea levels would mean for the impact of waves of the coastlines. Zoon could down and off simulates these changes in a way for tank as a wave travels from deep to Shallow Water it is met by a rising sea bed the friction dissipates the energy of the wave and it breaks normally that happens before it reaches the coast. That almost before us when i mean an increase in sea levels would mean that many waves that now break long before the dike would instead approach the dike with a far greater mass of water of course on. Those waves would put more pressure on the dike and possibly wash over a lot stream shastri and indict all the bush here and can. Highest sea levels amplify the power of waves the waves break later and hit the coast with far greater force. Even a modest rise in water levels can have a dramatic impact on a waves paua. Thats a sure we are today here the sea level and here comes a storm along so it floods everything that this elevation or below but now we have. Sea level here so we need only a smaller storm to flood the same area or we get the same storm its much higher. Than average Sea Level Rise of just a few decimeters a few tens of centimeters could make once in a century flood events become commonplace in relatively low lying coastal cities like new york the critical point would be reached at about a one meter rise in sea levels. Of the big apple submerged is this just a scenario out of the Science Fiction film or is it a preview of our future. On a geological time scale the last extreme rise in sea levels happened just a fraction of a 2nd ago but stone age humans were already living in settled communities archaeologists have found traces of abandoned settlements at the bottom of the baltic sea along the coast of present day gemini. The archaeological remnants discovered taya were abandoned some 7000 years ago the settlement was on the banks of a huge freshwater lake at the end of the last ice age sea levels began to rise a channel of water from the north sea swept over a land bridge washing away the prehistoric settlement but its traces remained. Before we found the item so the death of almost 2 meters this is an x. Made from. Dust and these are typical tools used by hunter gatherers who lived here they caught fish and hunted seals. The people who lived in the stone age settlements were forced to retreat from the rising sea. Bed for upset so i around 6500 b. C. E. The sea level was around minus 20 meters from the vehicle over the next 2000 years it rose by 20 meters. Sponsored the entire like basin was transformed into a marine marginal sea he was on the. Fish bones found in the area allowed researches to estimate how quickly the freshwater lake was consumed by the baltic sea within just a few centuries freshwater fish were replaced by salt water species the landscape had been flooded by the encroaching sea water. The ties that if the sea mentioned People Living here would have observed the rising sea levels and understood what the sea was creeping closer and claiming more and more land of the birds. The threat of being displaced by rising sea levels is something people in europe have not faced for several 1000 years thats too to an unusual period of stability which began after the last ice age. So 20000 years ago see there was about minus 120 meters below todays values but then as the world war sea levels rose about for me to per century sometimes a bit faster but thats the average rate and they kept on going all the way up until about 7000 years ago when sea levels then were constant and that is the period when civilizations ago. Around the world over thousands of years a coastal infrastructure has taken shape cities were built right by the sea and opportunities for trade business and prosper. Flourished there would have this was dependent on the comparative stability of sea levels. Human civilization is very much product of stable sea levels. Or systems of thinking also troops as a constant. Mean sea level is a day too so if it starts to change that makes what we do about start to get messed up so. Were moving into a new epoch where were going to have to change some of our thinking. So when did this new park begin satellites began tracking sea levels only a few decades ago to more fully map this trend oceanographers and could then end of embarked on a search for old data. The 1st sea level measurements dates back to the 17th century. Since the mid 18th hundreds there have been around 70 or 80 tide gauges around the world that allow us to assess the change in sea levels not to claim. One of these pages is on helicopter land off the northern coast of gemini since 885. 00 the tide gauge there has been taking continuous measurements that wealth of data is held in a special archive in the town of turning in nose in gemini. For research as such tropes of data are the only way to determine whether the recent rise in Mean Sea Levels is simply a natural fluctuation all part of a longer term trend that data is clear i Mean Sea Levels have been rising since the 19th century and more recently the pace has changed. Any response in sea level started rising more quickly at the end of the 19th century. Initially by around the one millimeter per year. After the 960. 00 s. And seventys so that trend accelerated. Reaching the current 3 millimeters per year i mean we meet up with. Mean sea levels have risen by almost 20 centimeters since the turn of the 20th century. But that is a global mean which can vary widely from region to region in new york city for example sea levels rose 30 centimeters during that same time frame. An email on trident im sure you can see levels do not rise evenly like when i feel this paddling pool whats your answer water masses are distributed around the world by ocean circulation winds blow the water from one side to another and redistribute it as a result sea levels rise on one side but are lower on the other the mere will speed up from off to on the ocean currents and wind push masses of water against the coasts causing variations in sea levels and the earth itself is also moving under our feet some coastlines are rising while others a sinking new york city for example is located in an area that is sinking that contributes another one millimeter a year to the rise in sea levels in sweden meanwhile the landmass is rising by almost one centimeter per year. And i all of these processes mean that regional sea levels can differ significantly from the global mean operation come. Out its the global Mean Sea Level that forms the Reference Point to assess changes across time and place. And as live a man studies the impact of Climate Change on the worlds oceans he said coauthor of the Intergovernmental Panel on Climate Change oh i. P. C. C. Reports the Gold Standard survey of Climate Science issued every 5 years. Weve only recently begun projecting the rise in sea levels for a long time we couldnt say how much it was increasing by. Predicting sea levels is one of the key challenges facing scientists today projections of future Global Warming have grown increasingly sophisticated but when it comes to sea levels this kind of modeling is still in its infancy for towns and cities on the coasts reliable predictions are a matter of final importance in the next in the last report was the 1st to include projections for the rising sea levels expertly said we cant provide a worst Case Scenario only the most likely scenario which leaves a lot of scope for uncertainty just. One of the factors explaining the rise in sea levels is comparatively easy to quantify water expands as it warms a process called thermal expansion the 2nd factor could soon become the driving force the loss of ice. For researches melting ice is a confounding factor as more ice melts they have to revise their projections upwards the i. P. C. C. Is most pessimistic estimate predicts a rise of 110. 00 centimeters by the end of the century but even that projection has been called into doubt few of the. Reasons in the we dont really know what the worst Case Scenario might look like a tsunami also in that. Most people dont realize one. Of the laws theyre. Putting. So if you look at hiring a new port to make a honey mass similar to most mass what youll see has we start off by in the middle of the sides and the honey from the middle is falling to the edges so that the honey in the middle is deforming under what we call a gravitational driving stress and the honey is trying to float. The ice is flow velocity will decide the fate of the ice sheet covering greene and the more that velocity increases the more of greenlands ice mass will be lost to the ocean. Greenlands ice cap is gigantic. Taken together it encompasses about 2700000 gigatons of ice until 1990 the ice mass was fairly stable. Is in the past 20 years greenland has lost an average of 266. 00 gigatons of ice a year contributing to a rise of 0700000 meters per year if all the ice were to melt sea levels would rise by more than 7 meters. William colgan is on the ground tracking developments in greenland if enough snow were to fall further inland losing so much ice to the sea would not be such a problem. For this. Area. That is just so. That is dealt the start finish in. Greenland has the worlds 2nd largest ice sheet half a century ago measurements taken by scientists in the northwest of the country showed that fresh snow kept adding new layers none of it melted. To assess whether the actions changed in recent decades William Colgan and his colleagues are extracting ice cause any changes could have a profound impact on Greenland Ice cap the team examines the cause for any signs of dense ice which could only be due to melted snow. The most powerful inference for finding from the ice cores is that when we look at today we see every year the snow is interrupted by this hard thick layer where the snow has melted and weve frozen this hard clear ice. About 25 percent of the fresh snow that had been replenishing the ice for thousands of years is now melting that could set off a feedback loop that would threaten key aspects of the ice sheet its thickness. So you picture the ice sheet sort of and this is the ground for the ocean has this shape hypocenter flow at the sides so as the ice sheet. Begins to melt. It gets slower it can as it gets slower its moving dale into warmer layers of the atmosphere is called high or low and you get this feedback because the farther the lower the ice melts the lower elevation there is for problems the more melts and the more melts lower the columns and you get this feedback. Such feedback loops make it difficult for scientists to make accurate projections the heights of the ice sheets is just one factor another is its color. If we think about like of this is a sheet surface. Really winds so its relatively reflective generally. About 80 percent of the sunshine that hits the snow surface. But through a variety of processes as the surface becomes darker as this no angels grows the surface becomes darker. Then you know from a surface that used to reflect 80 percent of the sunlight to one that might only reflect now 40 percent of the sunlight and this becomes a feedback because the more sunlight that absorbs the warmer becomes in the darker the color of the darker warmer darker warmer darker warmer theres this positive feedback we call the feedback loop. As scientists discover more about the feedback loops that effect the ice they have to widen the parameters of their full costs. But coastal towns and cities need reliable predictions to prepare for rising sea levels. Things easy if they get it wrong if they miscalculate the future rising sea levels and underestimate the risk of flooding and the cost could be immense means. For the city of venice the accuracy of these projections is a matter of vital importance parts of the city are less than one meter above the water and as the pace of the Sea Level Rise continues to accelerate flooding has grown more common and venice every centimeter counts. In these moments for the next century then hes has a solution. The 1st warning came in 1906 when floodwaters reached a height of nearly 2 meets his. Scientists calculated that in extreme events like this would happen only once every 200 years. In venice still decided to take precaution this. Hell surratt hes drew up a plan that would close off the lagoon in an emergency the massive flood barrier was called the movie project. And. Most consists of 78 movable gates fixed to the floor when a high tide. Comes compressed air raises the floodgates the lagoon and the city is separated from the sea construction work began in 2003 and still isnt complete but theres a catch might not be high enough to be. Mentioned this system considering the i. P. C. C. Scenarios. In. The late ninetys and we have to concede there warst scenarios that these 60 centimeters of Sea Level Rise in the next century and and under current projections the sea level is expected to rise more than a meter in this century thats more than the 5 and a half 1000000000 euro moser project could handle. If. There will be 2 meters of Sea Level Rise will have to. Have to do Something Else more natale than is the entire coleslaw and. In the mediterranean. The latest i. P. C. C. Report says this was a Case Scenario is unlikely but not impossible but to me to rise in sea levels by 2100 cannot be ruled out between house gas emissions and. If that happens up to 200000000 people could be displaced. Until recently we had no idea thats. Such a swift rise was possible. But now a group of scientists have challenge this assumption sea levels can change in dynamic fashion at times it can be very sudden. Antarctica and greenland have enough frozen water to raise sea levels by 66 meters. Theres no stimulus passed this Sea Level Rise after the last ice age took place between 14814400 years ago if you over 400 years global sea levels rose by approximately 60 meters thats 4 meters per century and incredibly fast increases in the gun to known engine for a long time scientists believed that the Antarctic Ice sheet is more stable than greenlands they thought antarctica was just a slumbering giant that occasionally discharged an iceberg into the sea. Sea currents carried the icebergs along the same route through what is called the iceberg alley towards chile as they approach warmer waters they melt. That pattern gave colas scientist mike veba an idea if he could count how many icebergs have traveled through this alley in the past he could calculate how much ice antarctica stand still lives. There how to find a key to unlock the past a past thats not to weigh at the bottom of the Antarctic Ocean at the depths of modern 3000 meters.