Glacier Bay National Park is a protected reserve of glacier activity. The amount of visitors is heavily regulated to something like 1 or 2 cruise ships at a time and only 2 smaller ships. The entire park was once a receding glacier that is now made up of a dozen or so smaller glaciers, the water you see in the background was once covered in glaciers. Before you start blaming George Bush for this, most of the mass of the glacier activity receded before 1900.