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 the December sky.

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<strong>Munich, Germany:</strong> "Never Again," a work by artist Walter Kuhn to mark the 100th anniversary of the end of World War I, fills Munich's Königsplatz.

Photos: 2018's best travel photos

Munich, Germany: "Never Again," a work by artist Walter Kuhn to mark the 100th anniversary of the end of World War I, fills Munich's Königsplatz.

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<strong>Xinjiang, China:</strong> Red peppers are aired following the fall harvest in northwest China's Xinjiang Province.

Photos: 2018's best travel photos

Xinjiang, China: Red peppers are aired following the fall harvest in northwest China's Xinjiang Province.

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<strong>Wallops Island, Virginia: </strong>An Antares rocket sets off from NASA's Wallops Flight Facility en route to the International Space Station, where it will deliver vital research materials, crew supplies and vehicle hardware. <br /><br />

Photos: 2018's best travel photos

Wallops Island, Virginia: An Antares rocket sets off from NASA's Wallops Flight Facility en route to the International Space Station, where it will deliver vital research materials, crew supplies and vehicle hardware.

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<strong>Volcán de Fuego, Guatemala: </strong>Close to 4,000 people were evacuated from their homes in November when Guatemala's Fuego volcano erupted, spewing ash and lava.

Photos: 2018's best travel photos

Volcán de Fuego, Guatemala: Close to 4,000 people were evacuated from their homes in November when Guatemala's Fuego volcano erupted, spewing ash and lava.

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<strong>Valley of the Gods, Utah: </strong>A team of international base jumping athletes rig a 503-meter slackline in Utah's spectacular Valley of the Gods. <br />

Photos: 2018's best travel photos

Valley of the Gods, Utah: A team of international base jumping athletes rig a 503-meter slackline in Utah's spectacular Valley of the Gods.

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<strong>Yerevan, Armenia: </strong>The Armenian Genocide Memorial complex, Tsitsernakaberd, was built in 1967 in the Armenian capital of Yerevan to commemorate the approximately 1.5 million Armenians killed in the Ottoman Empire between 1914 and 1923.

Photos: 2018's best travel photos

Yerevan, Armenia: The Armenian Genocide Memorial complex, Tsitsernakaberd, was built in 1967 in the Armenian capital of Yerevan to commemorate the approximately 1.5 million Armenians killed in the Ottoman Empire between 1914 and 1923.

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<strong>New Delhi: </strong>The Lotus Temple, made up of 27 free-standing marble-clad "petals," is a Bahá'í House of Worship and one of India's most popular sights.

Photos: 2018's best travel photos

New Delhi: The Lotus Temple, made up of 27 free-standing marble-clad "petals," is a Bahá'í House of Worship and one of India's most popular sights.

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<strong>Dhaka, Bangladesh:</strong> In Bangladesh, Hindu devotees sit together on a temple floor to observe Rakher Upobash celebrations. <br />

Photos: 2018's best travel photos

Dhaka, Bangladesh: In Bangladesh, Hindu devotees sit together on a temple floor to observe Rakher Upobash celebrations.

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<strong>Uji, Japan</strong>: Byodoin Temple, built in the 10th century, is a Buddhist place of worship and a UNESCO World Heritage site. <br />

Photos: 2018's best travel photos

Uji, Japan: Byodoin Temple, built in the 10th century, is a Buddhist place of worship and a UNESCO World Heritage site.

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<strong>Paris: </strong>The Louvre is the world's largest art museum and is home to around 38,000 exhibits. It receives more than eight million visitors a year.

Photos: 2018's best travel photos

Paris: The Louvre is the world's largest art museum and is home to around 38,000 exhibits. It receives more than eight million visitors a year.

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<strong>Amberley, United Kingdom</strong>: An enchanting mist fills lower-lying areas in South Downs National Park, which is in West Sussex near Amberly, England, in early October.

Photos: 2018's best travel photos

Amberley, United Kingdom: An enchanting mist fills lower-lying areas in South Downs National Park, which is in West Sussex near Amberly, England, in early October.

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<strong>Katsuta, Japan</strong>: Visitors wander through a field of bright red kochias (summer cypress) at Hitachi Seaside Park in Katsuta, east of Tokyo. In early to mid-October, these kochias turn from green to red and become a photographer's paradise.

Photos: 2018's best travel photos

Katsuta, Japan: Visitors wander through a field of bright red kochias (summer cypress) at Hitachi Seaside Park in Katsuta, east of Tokyo. In early to mid-October, these kochias turn from green to red and become a photographer's paradise.

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<strong>Stuttgart, Germany: </strong>Revelers ride a chain carousel at the 173rd Cannstatter Volksfest, a three-week long beer festival and fair. Stuttgart is in southwestern Germany, about a two-hour drive from the French border.

Photos: 2018's best travel photos

Stuttgart, Germany: Revelers ride a chain carousel at the 173rd Cannstatter Volksfest, a three-week long beer festival and fair. Stuttgart is in southwestern Germany, about a two-hour drive from the French border.

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<strong>Zakynthos, Greece</strong>: The Blue Caves in the Bay of Skinari on the Greek island of Zakynthos in the Ionian Sea are one of the island's top tourist attractions. The water's incredible color comes from special light reflections.

Photos: 2018's best travel photos

Zakynthos, Greece: The Blue Caves in the Bay of Skinari on the Greek island of Zakynthos in the Ionian Sea are one of the island's top tourist attractions. The water's incredible color comes from special light reflections.

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<strong>Milan, Italy:</strong> This striking image is taken at the "Inside Magritte" multimedia path at the Fabbrica del Vapore (Steam Factory), an arts center in this northern Italian city.

Photos: 2018's best travel photos

Milan, Italy: This striking image is taken at the "Inside Magritte" multimedia path at the Fabbrica del Vapore (Steam Factory), an arts center in this northern Italian city.

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<strong>Arolla, Switzerland</strong>: In mid-October in Arolla, western Switzerland, visitors throw stones in the "Blue Lake." Algae and glacial clays colors the water this vivid blue.

Photos: 2018's best travel photos

Arolla, Switzerland: In mid-October in Arolla, western Switzerland, visitors throw stones in the "Blue Lake." Algae and glacial clays colors the water this vivid blue.

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<strong>Trieste, Italy: </strong>At the 50th Barcolana regatta in Trieste, Italy, boats sail past the Victory Lighthouse. This historic regatta is held annually on the second Sunday of October.

Photos: 2018's best travel photos

Trieste, Italy: At the 50th Barcolana regatta in Trieste, Italy, boats sail past the Victory Lighthouse. This historic regatta is held annually on the second Sunday of October.

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<strong>Weng'an, China</strong>: This aerial shot depicts kayaks moored on the Jiangjie River in Weng'an County, which is in southwest China's Guizhou Province.

Photos: 2018's best travel photos

Weng'an, China: This aerial shot depicts kayaks moored on the Jiangjie River in Weng'an County, which is in southwest China's Guizhou Province.

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<strong>Rotterdam, the Netherlands: </strong>This is the Cube House in Rotterdam -- 38 cube-shaped pile dwellings and 13 business cubes. The Cube House was designed by architect Piet Blom.

Photos: 2018's best travel photos

Rotterdam, the Netherlands: This is the Cube House in Rotterdam -- 38 cube-shaped pile dwellings and 13 business cubes. The Cube House was designed by architect Piet Blom.

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$<strong>\North Tyneside, United Kingdom</strong>: A surfer heads toward the North Sea at sunrise in North Tyneside in northern England.$

Photos: 2018's best travel photos

\North Tyneside, United Kingdom: A surfer heads toward the North Sea at sunrise in North Tyneside in northern England.

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<strong>Seljalandsfoss, Iceland:</strong> Iceland's Seljalandsfoss waterfall features a 60-meter drop (197 feet) and is part of the Seljalands River. Visitors here are able to walk behind the falls and explore the cave behind.

Photos: 2018's best travel photos

Seljalandsfoss, Iceland: Iceland's Seljalandsfoss waterfall features a 60-meter drop (197 feet) and is part of the Seljalands River. Visitors here are able to walk behind the falls and explore the cave behind.

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<strong>Phimai, Thailand: </strong>One of the largest Khmer temples in Thailand, the centerpiece of Phimai Historical Park is the restored ruins of the Prasat Phimai sanctuary.

Photos: 2018's best travel photos

Phimai, Thailand: One of the largest Khmer temples in Thailand, the centerpiece of Phimai Historical Park is the restored ruins of the Prasat Phimai sanctuary.

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<strong>Pucón</strong><strong>, </strong><strong>Chile: </strong>Villarrica -- seen here from the town of Pucón -- is one of Chile's most active volcanoes. Its last major eruption was in 2015. <br />

Photos: 2018's best travel photos

Pucón, Chile: Villarrica -- seen here from the town of Pucón -- is one of Chile's most active volcanoes. Its last major eruption was in 2015.

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<strong>New York City: </strong>The "Tribute in Light" is an art installation lit annually in New York on September 11. Searchlights are used to create two vertical columns of light representing the Twin Towers.

Photos: 2018's best travel photos

New York City: The "Tribute in Light" is an art installation lit annually in New York on September 11. Searchlights are used to create two vertical columns of light representing the Twin Towers.

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<strong>Moscow: </strong>Zaryadye Park opened near the Kremlin in September 2017. One of its highlights is the 70-meter "floating bridge" designed by Diller Scofidio + Renfro, the architectural studio behind New York's High Line Park. <br />

Photos: 2018's best travel photos

Moscow: Zaryadye Park opened near the Kremlin in September 2017. One of its highlights is the 70-meter "floating bridge" designed by Diller Scofidio + Renfro, the architectural studio behind New York's High Line Park.

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<strong>Polignano a Mare, Italy: </strong>The town of Polignano a Mare, in southern Italy on the Adriatic coast, played host in September to the Red Bull Cliff Diving World Series.<br />

Photos: 2018's best travel photos

Polignano a Mare, Italy: The town of Polignano a Mare, in southern Italy on the Adriatic coast, played host in September to the Red Bull Cliff Diving World Series.

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<strong>Valais, Switzerland:</strong> There's a 100-meter ice tunnel and ice chamber inside Switzerland's Rhone Glacier. It's cut fresh each year and the season runs from June to October. <br />

Photos: 2018's best travel photos

Valais, Switzerland: There's a 100-meter ice tunnel and ice chamber inside Switzerland's Rhone Glacier. It's cut fresh each year and the season runs from June to October.

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<strong>Rome: </strong>What's more spectacular than St Peter's Basilica? Two St Peter's Basilicas. Photographer Tiziana Fabi caught this reflection in a puddle in September. <br />

Photos: 2018's best travel photos

Rome: What's more spectacular than St Peter's Basilica? Two St Peter's Basilicas. Photographer Tiziana Fabi caught this reflection in a puddle in September.

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<strong>Hunan province, China: </strong>This aerial shot shows a farmer raking rice crops for air-drying. This year, China marked its first Farmers' Harvest Festival on September 23.

Photos: 2018's best travel photos

Hunan province, China: This aerial shot shows a farmer raking rice crops for air-drying. This year, China marked its first Farmers' Harvest Festival on September 23.

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<strong>Moscow:</strong> This aerial views shows the unusually shaped building at 13 Nezhinskaya Street, a circular house in Moscow's Ochakovo-Matveyevskoye District.

Photos: 2018's best travel photos

Moscow: This aerial views shows the unusually shaped building at 13 Nezhinskaya Street, a circular house in Moscow's Ochakovo-Matveyevskoye District.

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