Rising sea levels, pollution, and increasing stresses on marine species and areas are major challenges confronting marine ecosystems as a result of climate change. In this chapter the author reviews the major changes in marine environments which natural scientists expect to occur because of elevated levels of greenhouse gases (GHG) in the atmosphere and considers their general implications for the presence of living organisms and supply of marine ecoservices. The chapter then focuses attention on the insights obtained from a Norwegian investigation of the economic impacts of GHG-induced changes in marine ecosystems. Thereafter GHG-induced losses of coral reefs and their potential economic impacts are discussed. Proposed policies for responding to predicted changes in marine ecosystems are examined, followed by a discussion of building resilience in the context of marine ecosystems.