Havana  - Cuban revolutionary leader Fidel Castro appeared on state-run television over the weekend for the first time in more than a year, during a meeting with Venezuelan students that showed him in good health and humour.

The six-minute video was recorded on Saturday, according to an announcer, during a discussion with recent graduates of the law school of Carabobo University, which is named after the retired Cuban leader.

Castro, 83, was dressed in sports clothes and spoke in a firm voice as he discussed the dangers of climate change during the animated conversation.

"We are facing very grave occurrences, I would say, grave for survival," said Castro, who stepped down as Cuban president in July 2006 during a serious illness.

"The problem of two degrees of higher temperatures will cause the melting of the Antarctic polar ice cap, not to mention Greenland," he said, noting that the US government has included climate change in the list of factors that threaten its security.

"They are discussing who will be the last to die," said Castro, provoking laughter from the students with whom he reportedly spent more than three hours.

Castro relinquished control of the Cuban state to his brother, Raul, three years ago, and has not appeared in public since, though officials have released photographs and rare videos of him during that time.

The last broadcast video appeared in June 2008 showing the Castro brothers with Venezuelan President Hugo Chavez. Those images, which were not accompanied by audio, showed the ailing leader in apparently worse condition than as he appeared this weekend. (dpa)