A、The earth movement. B、The volcanic eruption. C、Warmer air temperatures. D、The glacier’s special location. C

Experts warned recently that a major glacier in Greenland is quickly melting and falling into the Atlantic Ocean. (3)If the entire glacier in the northeast of Greenland melts and falls, global sea levels could rise by a half meter. The study, published in the journal Science, said the glacier melted three times faster than earlier. The glacier is losing 5 billion tons of mass per year, according to the study. The glacier is dumping many icebergs into the ocean. It will raise sea levels in future decades, Jeremie Mouginot wrote. He is the study’s lead author and a professor at the University of California, Irvine.
    (4)Warmer ocean water is eroding the glacier from below. Warmer air temperatures are melting it from above. Another Greenland glacier is also melting, but not as quickly because it is in a protected location.
3. What will make the global sea levels rise by a half meter?
4. What leads to the glacier’s melting?