“The fact that there is ongoing climate change in the world is completely clear and we ought to learn from that,” he said on Friday.
The king was speaking at a press conference as part of the Norwegian royal family’s visit to Sweden.
“We ought to try thinking the unthinkable,” he added, reminding the gathered press corps of the Boxing Day tsunami catastrophe.
He expressed horror that a society as advanced as that of the United States, with all its technical knowledge and its access to information, still had not been able to get to grips with the tragedy as it unfolded.
“The catastrophe just grows and grows for them too,” said the king, comparing the effects of the hurricane to the catastrophe.
King Carl Gustaf avoided being drawn into more detailed speculation about the direct causes of the hurricane disaster, but it was clear from his speech that he was shaken by the pictures coming through from New Orleans and other affected areas.
The Norwegian and Swedish royal couples attended the press conference in the old Stock Exchange building in Stockholm’s Old Town after visiting the Nobel Museum there.
The atmosphere between the couples was said to be warm and the Norwegian guests said that they had appreciated the visit. But when the king was asked why the visit was so important, he was somewhat vague.
“We are showing that our two countries are still neighbours and brothers,” he said.
“One and the same,” interrupted King Carl Gustaf, who emphasised the opportunities for further developing Swedish-Norwegian economic cooperation, a subject which was discussed during a business seminar on Friday morning.
The royal families later visited Mälsåker Manor House by Lake Mälaren, where during the Second World War Norwegian soldiers were trained under the guise of being policemen. After the German collapse, they took control of their homeland.
King Harald and Queen Sonja described the strong impression the visit made on them, not least because Sonja’s older brother was in the police troops during the war. Until now, very little of the police operation has been known in Sweden.