Tuvalu's Prime Minister says the option of litigation remains open if no progress is made in international climate talks.nele Sopoaga, whose low-lying country is one of the most at risk from rising sea levels, says trying to make other countries aware of Tuvalu's plight is difficult, but he remains optimistic an agreement can be reached this year.Mr Sopoaga says it is also difficult when major countries like the United States and Australia continue to argue about climate change and struggle to push through any meaningful legislation.\The time for arguing over the science is over. It is very