1. Jakarta is vulnerable to sinking because it is located in the northwest coast of the Java Sea and it also lies on a low flat basin at the mouth of the Ciliwung River on the Jakarta Bay making Jakarta get flooded because of the rising sea level.
2. The government wanted to help the city not drown in water so they are trying to strengthen the existing sea wall around the northern part of the city.
3.The biggest issue of course is whether the country can afford the cost, which is expected to be about $40 billion USD over 20 years. Also there is still the technical challenge of gathering the large amount of soil that will be required to build the islands. Not only that but the cities are very populated.
Critical thinking: I think the biggest hurdle/problem is the amount of money they will need to get or spend because they cannot afford the cost. -Sierra Lee