Travellers who pay extra dollars to offset their carbon emissions on flights have not achieved much to reduce their carbon footprint, an Australian study has found.
As technology makes flights cheaper and affluence grows in countries like China and India, the global demand for travel continues to outstrip the de-carbonisation efforts of tourism operations, researchers have revealed.
The study, published in Nature Climate Change on Tuesday, found the tourism sector accounts for eight per cent of global greenhouse gas emissions with the true environmental cost of the industry quantified for the first time.
Unlike previous studies, the research led by Integrated Sustainability Analysis took into account the carbon emitted directly during tourism activities, from shopping and food to accommodation and transport, across 160 countries.
The study found tourism's global footprint has increased from 3.9 to 4.5 gigatonnes of carbon emissions between 2009 and 2013 - nearly four times more than previously estimated.
The increase in global tourism and its emissions has "cancelled out all carbon intensity reductions", the study said.
Affluence in countries such as the United States and growing middle-classes in China and India has turned tourism into a more carbon-intensive activity, with travellers spending their money on longer flights to reach exotic destinations and participating in further consumption of goods through shopping and hospitality.
Meanwhile, visitors from low-income countries consume a high proportion of unprocessed food and use road transport with little commercial hospitality services, which translates to a smaller carbon footprint.
Dr Arunima Malik, researcher and University of Sydney lecturer, said travellers had to look at their whole trip, and not just their flight, to consider their carbon footprint.
"Whether it's public transport or a more carbon intensive mode (of transport), that all comes together and is part of your carbon footprint," Dr Malik told AAP.
Dr Malik said the tourism industry could contribute to its own eventual decline if it does not take measures to offset emissions, with the industry's global footprint forecast to reach 6.5 gigatonnes of carbon emissions by 2025.
The researcher hoped the "eye-opening" research would inform conversations ahead of the next meeting of the Paris Agreement in 2023.
"Our holidays destinations that we love going to, such as coastal areas, winter locations, the Great Barrier Reef, they're all vulnerable to the effects of climate change," she said.
"It's likely that these destinations that we love are going to undergo drastic changes in coming years if we don't protect them."
Australian Associated Press