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.
When we first approached Viking Ingvar docked in St. Petersburg, the first thing that struck us was how much larger it was than other river boats on which we have sailed. Unlike Viking River Cruises' European ships, which typically carry 150 guests (new longships carry 190), Viking Ingvar carries up to 206 guests.