By the end of the century, experts predict that we could see between two and eight feet of sea level rise.

Some cities, like Miami and New York, are already dealing with flooding at high tides and many cities are experiencing worse storm surges.

Cities are doing a lot to try to prepare, but a new book on sea level rise makes the argument that the seas will still transform our cities.

We build cities on the water.

Miami, New York, Tokyo, Mumbai, Lagos, Los Angeles — look anywhere in the world and humanity has decided that the places we want to congregate look out to sea. Close to 40% of the US population lives in coastal counties. Many of the most expensive and desirable locations in coastal cities are the ones with the best access to the ocean.

But these oceanside places are becoming more and more vulnerable to rising seas, as journalist Jeff Goodell details in his new book, "The Water Will Come: Rising Seas, Sinking Cities, and the Remaking of the Civilized World."

Goodell's book is a journey to the cities and towns around the globe that are trying to figure out how to adapt to sea levels that are continuing to rise. He travels to small Alaskan villages, to the megacity of Lagos on the coast of West Africa, and returns throughout the book to Miami, one of the urban areas that best demonstrates the many challenges of trying to keep the ocean at bay.

"Miami as we know it today, there's virtually no scenario under which you can imagine it existing at the end of the century," Goodell told Business Insider. As a large low lying city built close to a storm-prone coast on top of land that makes coping with sea level rise particularly complicated, Miami has serious sea level rise issues to deal with.

It's not that the city itself — or Miami Beach, technically another nearby city — will totally disappear or that all of the millions of people in the region will relocate. Transformation, adaptation, and engineering will help some people stay.

But there are a lot of people who will need to move as the risk of remaining in place grows, according to Goodell. That might be because of financial risk as banks become less willing to supply mortgages for houses in flood-prone regions; it may be because of physical risks as more intense storms bring dangerous surges on top of already higher waters.

That is likely the case — depending on how effective mitigation efforts can be — for communities all over the world, from parts of New York City that are still recovering from Hurricane Sandy to entire nations on Pacific islands.

Sandy caused shocking amounts of flooding. AP/John Minchillo

The problem with rising waters

Every place faces unique challenges when it comes to sea level rise. For geological reasons, water level is rising faster in some place — like South Florida — than others.

Because of the type of land they're built on, cities like New Orleans, Louisiana and Norfolk, Virginia are losing elevation as the water rises because of a process known as coastal subsidence. Miami and South Florida don't have that problem, as much of the ground underneath them is made of limestone.

But that creates a new issue. Limestone is porous, which means that water rises up from below, meaning it's impossible to build walls to keep rising seas out as has been done in the Netherlands.

Still, there are some common factors that pop up in all cities where sea level rise is an issue, many of which might surprise someone who hasn't immersed themselves in the facts about what this means for cities.

For one thing, the flood waters that you can already see in cities like Miami on sunny days with particularly high tides are not "clean sea water." Water comes up through sewers and drains and brings nasty stuff with it.

"In urban areas, the floods that pour into the city are not going to be luminous blue waters you'll want to frolic in on your Jet Ski," Goodell wrote in the book. "They are going to be dark, smelly, and contaminated by organic and inorganic compounds, including, in some places, viruses and human shit."

Another factor is that even a small amount of sea level rise can have a profound effect. We call some of the flooding that has started to occur more frequently in the absence of massive storm events "nuisance flooding," but that term may be misleading when you think about the huge problems that even a small amount of sea level change can cause. There's increased erosion, corrosion of structures, and the risk that seawater could contaminate drinking water supplies.

Plus, places that have only seen a gradual amount of sea level rise so far shouldn't necessarily expect that rate to remain constant. Goodell said that researchers who have examined Earth's geologic history say that when sea levels are rising, there's often a "pulse" where there is a lot of rise in a short period of time. In geological terms, that may mean several decades or even several hundred years, but some experts think we could be entering one of those pulses now.

Lower Manhattan has a plan to help mitigate flooding, but it can't be done everywhere. BIG Team/Rebuild By Design

Can you keep the water out?

According to Goodell, we can't stop sea level rise at this point, so we have to figure out how we're going to deal with it.

We've already emitted enough carbon dioxide into the atmosphere that a certain amount of sea level rise is guaranteed. Stopping emissions as soon as possible would help prevent the problem from getting worse but wouldn't change the fact that much of the world is going to see between two and eight feet of sea level rise by the end of the century, depending on the model you look at.

It's not that no one working on this. Parts of Manhattan are going to be protected by a series of systems known as the Big U that will surround the lower part of the island. In sections of Miami Beach, roads are already being raised, pumps have been installed, and there's talk of raising buildings as necessary. Beaches all over the East Coast are being replenished with new sand as the ocean eats them away.

But no matter what, we can't keep the water out everywhere. In some cases, people will be forced to move — and lower-income residents will likely struggle the most due to lack of resources.

"I want places to start to take this seriously; the kind of planning to keep places like Miami alive is going to take some time," Goodell told Business Insider.

New cities might have floating infrastructure or come up with ways to keep critical infrastructure safe in extreme events. There's a lot of opportunity for creativity, Goodell said. But older cities could experience more of struggle trying to retrofit themselves for rising waters. Some neighborhoods and communities will have to move.

"I hope people take [from the book] that we have to live differently," Goodell said.