A treaty to safeguard the future of the South Pacific nation of Tuvalu has come into force, Australian Prime Minister Anthony Albanese announced in Tonga on Wednesday. Tuvalu, which is threatened by rising sea levels, requested the support of Australia to help safeguard the nation. Under the agreement, 280 Tuvaluans a year will be able to live, work or study in Australia under a special visa. Australia will be obliged to respond when Tuvalu calls for assistance in the face of a major natural disaster, health pandemic or military aggression. Tuvalu, in turn, will mutually agree any new third-pa…