Six countries produce nearly 60 percent of global carbon dioxide emissions. China and the United States combine for more than two-fifths. The planet's future will be shaped by what these top carbon polluters do about the heat-trapping gases blamed for global warming. How they rank, what they're doing:
River cruise companies also have their own tipping policies. A handful, such as Scenic Tours, Avalon Waterways and Tauck, include gratuities in their overall price, while Viking River Cruises recommends that guests tip at the end of the trip at a rate of between Â£5 and Â£10 a day.
It is the parent company of Viking River Cruises and Viking Ocean Cruises. In 2015, the company began offering ocean cruises on ocean vessels that sail the coasts of Scandinavia and the British Isles, and the waters of the Baltic Sea and the Mediterranean Sea.