Some people fear that global warming will cause the large ice formations in the polar seas to melt, thereby warming the waters of those seas and threatening the plankton that is crucial to the marine food chain
Some scientists contend that it is unlikely that the melting process has begun, since water temperatures in the polar seas are the same today as they were a century ago
The mean air temperature above both land and water in the polar regions has not varied significantly over the past 100 years.