Question: what is the most important environmental concern today?
Answer: Deforestation. Each year, the U.S. population grows by more than 1,700,000 people. ... 
Air Pollution. While air quality has improved greatly in the last 50 years, it still remains an issue in many major cities with large populations. ... 
Global Warming. ... 
Water Pollution. ... 
Natural Resource Depletion.