Answer:
Lack of creativity
Step-by-step explanation:
The profession of engineering is one that is often ascribed to technical and rational process of dealing with nature. Although being rational and methodologically minded are important traits, however, the reason why an engineer will be required is more often because of novel issues and obstacles, because engineering is about problem solving.
Problem solving, more often than not, usually thinking outside the box to picture the possible alternative solutions that will take care of a scenario.
As the population is increasing and there is concern about global warming. The lack of creativity is an obstacle an engineer must overcome to develop the solutions to current limits of the practice.