Smog and pollution is a huge problem in modern environments. The rich world is better off than most considering the legal restrictions on pollutants, but there are plenty of problems in other parts of the world (such as Asia). Many of these problems stem from poor use of land and it can have drastic effects for the people living on this planet. The majority of the 7 billion people live in poverty and it is no wonder that most of them are looking for some way out. Hopefully with time, people will be able to see that spending money on optimizing the land is the best bet.
There are many scientists and land companies, such as those selling cheap land for sale, that are eager to get our land better optimized. Some of the governments in the western world and in Asia have been promoting better use of the land through grants and other government incentives. While most of the people who are getting involved in this type of optimization are scientists, there are plenty of farmers and lay people involved as well. Hopefully, this trend will continue so that humans can sustain the populations that we currently have.
That being said, optimization of land is going to be needed on a very large scale in order to make any real difference. People who are interested in getting involved should enter the field as there is plenty of profit in feeding people with cheaper resources. Although there are some barriers to progress in this field, there are plenty of able bodied individuals who can help to make this a reality.