He was focusing on observations of phytoplankton populations in the Arabian Sea during the summer monsoon, but by chance he looked at winter data. In the past two decades, the winter winds blowing over the Arabian Sea have become warmer, calmer, and more humid. The belief was that the Arabian Sea would become less productive from December to March. They found that winter chlorophyll-a in the Arabian Sea has been increasing steadily since the 1990s—as much as four times higher in some winters. The map above shows the trend—mostly increasing—in the Arabian Sea from 1996 to 2018.