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 planning your cruise, check with your travel agent or the cruise line about the tipping policy. Often the recommended tips, which run from about $10 to $20 per passenger per day, are published either in the cruise brochure or on the cruise line Web page. The cruise director will also remind passengers about how much and whom the cruise line recommends you tip.