Final answer:
The human population is experiencing exponential growth due to advancements in agriculture, medicine, and communication, as well as human migration. Even though fertility rates are declining, the large base population size leads to significant numeric increases. This growth poses potential environmental challenges due to the finite nature of resources.
Step-by-step explanation:
The world's human population is growing exponentially, which can be credited to several factors. Historical data has shown that advancements in various fields have allowed humans to increase the Earth's carrying capacity - the maximum number of individuals that an environment can sustain over a long period of time. Notably, improvements in agriculture, medical advances, and communication have played significant roles in this growth. Human migration has also contributed to a broader spread of populations globally.
Despite a decline in fertility rates and human reproduction being far below its biotic potential, the enormous base size of the current population means that even small growth rates can result in the addition of many millions of individuals to the global population. The speed at which the population grows has accelerated dramatically; it took only 12 years to go from six to seven billion people, showcasing the characteristic pattern of exponential growth.
However, there are concerns about the long-term sustainability of this growth, especially considering the finite nature of Earth's resources. The world's population is expected to continue to grow, although at potentially slower rates, but the issue of overpopulation and its environmental impact remains a significant challenge.