Global tourism's carbon footprint is four times bigger than thought, study says

By Susan Scutti, CNN

Updated 1:31 PM ET, Mon May 7, 2018

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<strong>Hamamatsu, Japan:</strong> Visitors come to Bentenjima Island from mid-November to mid-January, when the setting sun is framed by the torii gate, creating marvelous shots like this one. Click through the gallery for the rest of the best travel photos of 2018:<br />
Photos: 2018's best travel photos
Hamamatsu, Japan: Visitors come to Bentenjima Island from mid-November to mid-January, when the setting sun is framed by the torii gate, creating marvelous shots like this one. Click through the gallery for the rest of the best travel photos of 2018:
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<strong>Krasnoyarsk, Russia:</strong> Deep in the Siberian winter, with air temperature at about -16 C (3 F), a man fishes on the banks of the Yenisei River.
Photos: 2018's best travel photos
Krasnoyarsk, Russia: Deep in the Siberian winter, with air temperature at about -16 C (3 F), a man fishes on the banks of the Yenisei River.
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<strong>Kirkjufell, Iceland: </strong>The aurora borealis, or northern lights, are seen over Kirkjufell, a 463-meter mountain on the west coast of Iceland.
Photos: 2018's best travel photos
Kirkjufell, Iceland: The aurora borealis, or northern lights, are seen over Kirkjufell, a 463-meter mountain on the west coast of Iceland.
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<strong>New Delhi, India: </strong>One of the largest mosques in India, Jama Masjid was commissioned by the Mughal emperor Shah Jahan and completed in 1656.
Photos: 2018's best travel photos
New Delhi, India: One of the largest mosques in India, Jama Masjid was commissioned by the Mughal emperor Shah Jahan and completed in 1656.
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<strong>Lisbon, Portugal:</strong> A popular way to explore the Portuguese capital is to ride its distinctive yellow trams around the city's cobbled hills.
Photos: 2018's best travel photos
Lisbon, Portugal: A popular way to explore the Portuguese capital is to ride its distinctive yellow trams around the city's cobbled hills.
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<strong>Soshartyan, Hungary:</strong> As December temperatures fall below 0 Celsius (32 F), a church stands above a layer of fog in the Hungarian village of Soshartyan. <br />
Photos: 2018's best travel photos
Soshartyan, Hungary: As December temperatures fall below 0 Celsius (32 F), a church stands above a layer of fog in the Hungarian village of Soshartyan.
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<strong>Linfen, China: </strong>The Hukou Waterfall scenic spot lies on the border between north China's Shanxi Province and northwest China's Shaanxi Province.
Photos: 2018's best travel photos
Linfen, China: The Hukou Waterfall scenic spot lies on the border between north China's Shanxi Province and northwest China's Shaanxi Province.
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<strong>Cairo, Egypt: </strong>The mosque of Ibn Tulun is the oldest mosques in the Egyptian capital of Cairo standing in its original form.
Photos: 2018's best travel photos
Cairo, Egypt: The mosque of Ibn Tulun is the oldest mosques in the Egyptian capital of Cairo standing in its original form.
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<strong>San Sebastian, Spain: </strong>Dogs run free along Ondarreta Beach as a dramatic sunset takes over the December sky.
Photos: 2018's best travel photos
San Sebastian, Spain: Dogs run free along Ondarreta Beach as a dramatic sunset takes over t