DAVOS, Switzerland: Swedish teen activist Greta Thunberg on Tuesday slammed global inaction on climate change in front of the world's top business leaders, as the annual Davos forum faced up to the perils of global warming while bracing for an address from US President Donald Trump.

The 50th meeting of the World Economic Forum in the Swiss Alps resort got under way seeking to meet head-on the dangers to both the environment and economy from the heating of the planet.