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EARTH UNDER WATER FACTS
The floating sea of the Arctic doesn’t contribute to sea level rise.
Antarctica stores 90 percent of the world’s fresh water.
If all the Antarctic ice melted, sea levels would rise by 60 meters (197 feet).
If Antarctica, Greenland and all our glaciers melted, sea levels would rise by a total of 70 meters (230 feet), the maximum sea level rise we can have.
If sea levels rose by 70 meters, New York, London, Paris, Berlin, LA and Washington D.C. would all be flooded.
PAST
Over the last 50 million years, sea levels have varied considerably.
Carbon dioxide (CO2) is a greenhouse gas that has a major effect on global temperatures. High CO2 levels in our atmosphere correspond with high global temperatures and high sea levels, and with small amounts of ice near the poles.
Fifty million years ago, atmospheric CO2 was more than four times higher than today. It was so warm that there was no ice on the planet.
Fifty million years ago, sea levels were 70 meters higher than today.
Between 50 million years and 2 million years ago, both atmospheric CO2 and global temperatures decreased slowly; as a result, ice caps formed near the poles and sea levels went down.
Two million years ago was the beginning of a series of waxing and waning ice ages.
There was a warm and intermediate period between ice ages about 120,000 years ago, and sea levels were at least ten feet higher than today.
Our last ice age began about 70,000 years ago. Sea levels dropped dramatically as water became trapped in the ice sheets.
The peak of the ice age was 20,000 years ago. Sea levels were 120 meters (394 feet) lower than today.
Sea levels have only been stable for about 4,000 years.
New York
By Tilman Remme, Writer and Director11-13 April 2010
The last leg of our US filming trip is New York, one of my favourite cities.
New York City is even more exposed to sea level rise than London, as it is directly connect to the sea. And there are hardly any sea defences. If sea levels rose by 6 feet, the city’s underground installations would be in danger of flooding, and southern Manhattan would be inundated.
To find out how fast sea levels could rise in the future, we visit Rutgers University in nearby New Jersey. The scientists here are the experts on the rate of sea level rise after the last ice age. They have collected fossilized coral from the sea bed off Barbados. They determine the age of each coral sample, and take into account the depth at which they were found. Their conclusion: about 12,000 years ago sea levels rose by about 16 feet per century. Professor Peter Ward and others believe that the same could happen again in the next century, given the huge increase in CO2 of the last hundred years. After an initial sea level rise of 6 feet this century, the rate of sea level rise could increase to 16 feet per century. Which means that by the year 2200, sea levels will have risen by a total of 22 feet. Ouch.
We also visit Professor Jim Hansen, a leading NASA scientist. I ask what will happen if CO2 continues to rise at the current and constantly increasing rate. The question is valid. Some CO2/climate models predict that by the end of the next century, CO2 could reach 1,200 parts per million, corresponding with levels we last had 50 million years ago, when it was so warm that there was no ice on the planet. Professor Hansen replies that if we are so foolish to burn all our fossil fuels, Antarctica will go into rapid meltdown. Sea levels would rise by more than 230 feet by the middle of the millennium. This is our third, worst case scenario, predicted for the 23rd century of this millennium. If this happened, all our coastal cities and regions would be inundated by 2600, with little or no time to build adequate sea defences.
We go on a boat ride around Manhattan. The New York based oceanographer, Professor Malcolm Bowman, points out how the worst case scenario would affect the city. Manhattan would be flooded, up to the level of Manhattan Bridge.
But even then, humans would try to cope with the rising tides. The Dutch architect, Koen Olthuis, has made a plan for floating New York that could serve as a blueprint for coastal cities around the world. His idea is to build a vast ‘Hoover Dam’ around Manhattan and attach floating districts built on a new lightweight concrete foam material.
It’s our last day in the US and we have dinner with Professor Bowman. We talk about when sea level rise will noticeably affect us. Certainly, the young people of today will be confronted with it in their lifetime. Their children and grandchildren will be busy building sea defences. Humans will have to fight back. People will need all their ingenuity to meet the planet’s greatest challenge yet.
PRESENT
We currently live in a warm intermediate period after an ice age.
In the last 100 years, our CO2 levels have increased by 30 percent, mainly because humans have been burning fossil fuels like coal, oil and gas.
Our current CO2 levels correspond with CO2 levels we last had between 1 million and 3 million years ago, when global temperatures were higher and sea levels were 20 meters higher than today.
Currently, sea levels are rising by one foot per century.
The Netherlands
By Tilman Remme, Writer and Director27-29 July 2009
How do you make a film about something that hasn’t happened? At least not happened yet. About the great deluge that is forecast as a result of global warming, creeping in on our coastlines, destroying sea defences and inundating vast tracts of low lying land within centuries or even decades.
It’s the 27th July 2009 and I am on the Dutch island of Terschelling, one of the most beautiful spots of land in the Netherlands. Three months to go before we start production of Earth Under Water. Maybe I should film this place? The island is in the forefront of the global battle against the rising tides in the not so distant future.
I am here for a brief holiday. We go cycling and stumble across a number of curious yellow frames in the middle of one of the island’s nature reserves. I know this frame. Could it be? Yes, it’s the National Geographic frame, put up by a local artist, as Nat Geo Holland seems to be a sponsor of this unique habitat.
Terschelling consists of sand dunes, a long beautiful beach and of some fertile flat farmland in the back. The dunes protect the island against the sea in the north. In the south, there are levees to keep the sea at bay. But if sea levels rise enough, this island may have to be abandoned. Even if we don’t film here, there will be a chance to film beautiful coastlines around the world that are threatened by sea level rise.
We leave Terschelling wondering how future sea level rise could or indeed will change the face of the entire planet, eroding and flooding some of our most beautiful coastlines, at least if the worst predictions come true. How fast could sea levels rise? And by how much? When will the inundation begin, and when will it stop? We will have to do some in-depth research, talk to experts around the world, check what research has been done so far. To see how much time Terschelling may have before it’s lost to the sea.
25 January 2010
I visit the Netherlands. One quarter of the country is below sea level. Parts of Rotterdam are 25 feet below sea level. A vast river delta dominates the landscape. But the Dutch have one of the most sophisticated sea defence systems in the world. There are levees along the coast and along the river banks.
Powerful storm surge barriers are on standby to close their gates should a hurricane push the surging waters of the North Sea towards the coast and into the delta. I ask a local expert how the Netherlands would cope with future sea level rise. He says that it’s all down to the speed of sea level rise. At the moment, sea levels are rising at one foot per century. But the rate of sea level rise is increasing. Some leading scientists predict six feet in sea level rise this century, and an additional 15 feet in the next century. The expert believes that wealthy countries like the Netherlands could cope with six feet per century by building up their sea defences. But any faster than that would be extremely difficult to cope with. In the case of the Netherlands, you would have to build up river levees deep inland — otherwise the rising sea would push the river water upstream and flood the country from previously safe and higher lying areas. In some cases, rivers would have to be diverted, and smaller rivers would have to be pumped into larger rivers and into the sea. Six feet of sea level rise would be catastrophic.
The German climatologist, Professor Stefan Rahmstorf at Potsdam University has developed a number of climate models. They predict that sea levels could rise by as much as 1.9 meters, more than six feet, by the end of the century. We use this prediction as the basis of our first scenario in our film.
One alternative to building sea defences would be to build floating cities. The Dutch architect Koen Olthuis has designed floating houses and villages. In IJburg on the outskirts of Amsterdam, there are already entire floating communities. If sea levels rise, the floating houses or neighbourhoods will literally “go with the tide.” Another example of how humans will have to be inventive to deal with sea level rise.
FUTURE
Some leading climatologists expect temperatures to rise by up to five degrees Celsius this century, and for sea levels to go up by a maximum of six feet.
If sea levels rise by six feet, the coastlines of all our oceans will be affected.
Up to 50 percent of the world’s population is expected to live in coastal areas by the middle of the century.
America’s Great Lakes will not be affected by rising sea levels, as their shores are more than 70 meters above sea level.
Some scientist have calculated that our CO2 levels will triple or even quadruple in the next few centuries, as demand for fossil fuels increases by our growing population.
Some scientists predict that sea levels will rise by an additional 16 feet in the next century.
Some scientists predict that sea levels will rise by an additional 50 feet in the 23rd century, if our atmospheric CO2 levels triple.
New Orleans
By Tilman Remme, Writer and Director4 February 2010
I visit New Orleans for research. Like the Netherlands, New Orleans lies several feet below sea level. But Hurricane Katrina destroyed the local sea defences and flooded 80 percent of the city. Now, the US Army Corps of Engineers are building impressive new sea defences — powerful enough to withstand a second Katrina. The US Army Corps of Engineers shows us around. It’s February, and its pouring with rain. We get on a boat and are shown the new flood barrier in Lake Borgne, to the east of the city. Huge piles are rammed deep into the ground. We are told that New Orleans is built on ancient sediment, or mud, which makes the whole project even more difficult.
New Orleans’ new sea defences are costing the tax payer over 15 billion dollars. One day, once sea levels rise kicks in, coastal cities around the world may have to build sea defences that are similar to those in New Orleans. The costs of defending coastal cities against sea level rise will be enormous.
The people of New Orleans are exceptionally friendly. The entire city is an a mood of excited anticipation. Only a few days to go until the Super Bowl. A few days after my departure I hear that New Orleans has won!
But there is little time for the engineers. They work day and night to complete the project as soon as possible, in anticipation of future hurricanes.
