The forum's founder Klaus Schwab has seen vast changes in business,society and culture over the 50 years since he created the yearly gathering in the Swiss Alps. The meeting was initially was a forum for business leaders,but it is now also a key stop for policymakers and activists.
Following another year of extreme heat,bushfires and melting ice sheets,environmental issues are considered to be one of the top five long-term risks confronting the global economy,the World Economic Forum said last week,citing a survey of more than 750 decision-makers.
It said catastrophic trends like global warming,climate change and the extinction of animal species would top the agenda at the meeting when it begins on Tuesday.
The forum is shifting its recent focus from how technology is transforming lives to the environment and responsible business practices that promote jobs,fight climate change and work for both social good and profit-making.
The focus on environment could make for an uncomfortable subject for Trump,whose administration has called for expanded use of carbon-spewing coal,stripped away environmental protections and played down concerns among scientists about man-made climate change.
Trump has also moved to take the US out of the landmark 2015 Paris accord that aims to fight climate change.
Schwab says Trump would be welcome because of his role on the world stage,while Thunberg's presence would help keep the focus on the environment. Both will speak on the opening day.