UNITED NATIONS — U.N. Secretary-General Antonio Guterres has appointed the outgoing president of the General Assembly as the first special envoy for the oceans, seeking to galvanize efforts to protect the world’s seas.

Peter Thomson played a leading role at the first-ever U.N. conference on oceans in June. The 193 U.N. member states issued an urgent call for action to reverse the decline in the health and productivity of the world’s oceans.

U.N. spokesman Stephane Dujarric announced Thompson’s appointment Tuesday, saying the former ambassador for Fiji will promote action to implement the conference recommendations.

Thomson told reporters the major challenge facing the oceans is the change in climate, which affects the seas and the air that all people breathe. In his words, “accumulated human activity is putting us out of balance.”