Trade barriers are government-induced restrictions on international trade. Economists generally agree that trade barriers are detrimental and decrease overall economic efficiency; this can be explained by the theory of comparative advantage
A trade barrier is something that stops countries from freely trading with each other (this can be as a result of conflict)
For example, In China and India, through wars, a gradual trade barrier has been created due to the fact that the countries are going through warfare tension
Today the world's population is 7.5 billion. The world's population is changing because of the natural increase rate. The natural increase rate is the crude birth rate minus the crude death rate. Since the crude birth rate is higher than the crude death rate today, this would lead to a higher natural increase rate.