PORT-OF-SPAIN (Trinidad) - US ENERGY Secretary Steven Chu is warning that if countries don't do something about climate change, 'some island states will simply disappear'.

The energy secretary is travelling with President Barack Obama to the two-island nation of Trinidad and Tobago for a summit of the Western Hemisphere's democracies.

WASHINGTON - THE US Environmental Protection Agency shifted course and deemed carbon dioxide a health risk on Friday, in a turnabout important to global warming-related regulation.

'After a thorough scientific review ordered in 2007 by the US Supreme Court, the Environmental Protection Agency issued a proposed finding... that greenhouse gases contribute to air pollution that may endanger public health or welfare,' an EPA statement posted on the agency website read.

WASHINGTON - THE US government Friday unveiled guidelines for publicly-funded embryonic stem cell research limiting it to embryos developed in test tubes for would-be parents but never used.

The draft guidelines, issued by the National Institutes of Health, came in response to President Barack Obama's executive order on March 9 lifting a ban on embryonic stem cell research.