More and more holidays Mike Kelley / mpkelley.com

To help stop global warming, cancel that round-the-world holiday. Tourism has expanded so rapidly that it now accounts for 8 per cent of the greenhouse gases we belch into the air. That is up to four times previous estimates.

Arunima Malik of the University of Sydney, Australia and her colleagues estimated the annual greenhouse gas emissions of tourism in 160 countries. They say the industry emits around 4.5 gigatonnes (Gt) of carbon dioxide equivalent every year.

Previous estimates varied from 1 to 2 Gt per year. The team’s new estimates are higher because, as well as direct emissions from air transit, they also included indirect emissions. These include emissions from food production for tourists eating lavishly while on holiday, hotel upkeep and maintenance, and souvenirs. In 2013 this added an extra 1 to 2 gigatonnes.


What’s more, tourism’s annual carbon footprint has grown rapidly, from 3.9 Gt in 2009 to 4.5Gt in 2013. That looks set to continue. “We estimate that a business-as-usual scenario will increase the carbon footprint from tourism to 6.5 gigatonnes by 2025,” says Malik.

A wealth problem

Tourism is growing as people get richer. Perhaps unsurprisingly, the US is the biggest source of tourism emissions, due to both its own citizens travelling elsewhere and people from elsewhere visiting the US.

But other nations are catching up fast. “[The] strongest growth was seen in emerging economies such as China, India and Brazil, as wealthy citizens seek to travel to exotic destinations,” says Malik.

In line with this, figures released last month by the UN World Tourism Organization show that in 2017 Chinese people were the top tourism spenders. They shelled out US$258 billion, nearly double the US$135 billion spent by Americans.

“Flying less is one recommendation,” says Malik. But so far people’s desire for exotic holidays shows no sign of abating. “Growth in tourism-related expenditure is a stronger accelerator of emissions than growth in manufacturing, construction or service provision,” says Malik.

Journal reference: Nature Climate Change, DOI: 10.1038/s41558-018-0141-x