Interviewer: Many scientists predict that global warming will lead to more frequent and intense heatwaves. What is the primary reason for this prediction?
Scientist: The main reason is that _________.
A) the Earth's orbit around the sun is changing slightly
B) human activities are releasing greenhouse gases, trapping more heat in the atmosphere
C) volcanic eruptions are becoming more common, blocking sunlight
D) the ocean currents are slowing down, causing less heat distribution