On the short term (that being 100 years), the current defences would suffice, even if sea levels were to rise one meter (which is more than any scientist has so far predicted). Beyond that, we would need to upgrade our current defenses.
For the long term, different strategies are in place, such as partial surrender. See, the land in Holland is low because it was cut off from the sea and rivers by man-made dams. One island to the Southeast of where I live sunk away in the 1800s and an interesting development has taken place down there: the sea and the rivers brought in sand and mud and the land is now actually well above sea level. By surrendering coastal regions to the sea, the same development would provide us with (for instance) a 25km wide barrier, made by nature, virtually indestructable.
There are similar strategies, and very different ones. The point is: backed-up with 2000 years of knowledge and expertise and a modern defense system built to withstand storms that come once every 10.000 years or sea levels much, MUCH higher than global warming is expected to cause any time soon, there is little point to worrying about Holland.
London is much more likely to flood. So is Venice. Or Bangladesh. Lower Manhattan... You name it. But the list doesn't include Amsterdam.