Travelers are reducing their air travel across Europe in a trend that started in Sweden. "Flight shame," which goes by several different names depending on each country, is leading to a boom in rail travel as people become ashamed to fly. 

The multi destination holiday trend has led to travelers opting for overnight trains across Europe to cut back on their carbon foot print.

Air travel is a major contributor to climate change, accounting for 4% to 9% of total climate change impact. The aviation's rapid growth has allowed international aviation CO2 emissions to increase by 83% since 1990.

Grassroots initiatives are working to encourage travelers to take mass transit over airlines to their next destination. We Stay on the Ground, a group started by Maja Rosen, aims to recruit people to pledge to give up flying for one year. Rosen claims that more than 8,000 people around the world have made the pledge to give up flying for one year.

Rails are benefitting from the change, with rails in Europe experiencing as much as a 20% increase in tickets as the airline industry in Sweden and other European countries experiences a decline in sales. Sweden's domestic flights fell by 4.5% in the first-quarter of the year, as many travelers choose to give up flying for more eco-friendly modes of transportation.

Greta Thunberg, the 16-year-old activist and Sweden native, is helping push the trend forward. Thunberg was publicly recognized when she went on strike last year from school to bring attention to her government's inaction on climate change. Her protest led to protests around the world, with younger generations demanding that governments take climate change seriously.

Thunberg travels to events across Europe by trains and refused to fly to New York's United Nations Climate Action Summit due to the CO2 produced by air travel. A sailboat will take her to New York.

Environmental activists are choosing rail travel across Europe, with an increase in rail travel in Finland, Germany, Switzerland and the United Kingdom.

Air travel and shipping remains in high demand, with record demands for flights in many countries. Leisure flights and falling ticket prices are encouraging travelers in emerging countries to fly more often.

Aviation emits 860 million metric tons of carbon annually. Emissions from air travel are expected to increase by 300% to 700% by 2050 unless consumers change their transportation habits or the industry finds new ways to lower emissions.