This is the stark conclusion from the Envisioning Tourism in 2030 report, published by the Travel Foundation, which found destinations and tourism businesses "must take action now" on sustainability if they are to reach the goal.
It comes after global policymakers and climate planners attending Cop27 were urged to combine current measures with "significant" investments and incentives for bringing forth the greenest forms of transport, and limits on the most polluting.
The team behind the report used a "systems modelling" technique to explore future scenarios for global travel and tourism.
They found only one decarbonisation scenario that could match current growth forecasts and so double revenue and trips in 2050 from 2019 levels.
This scenario is achieved through trillion-dollar investments in all available decarbonisation measures and by prioritising trips which can reduce emissions most readily – for instance those by road and rail, and shorter distances.
"It’s clear that business as usual for tourism is neither desirable nor viable," said Menno Stokman, director at the Centre of Expertise Leisure, Tourism and Hospitality (CELTH).
"Climate impacts are already here, increasing in frequency and severity, with monumental costs for humanity and the environment that affect tourism more than most other sectors.
"Current decarbonisation strategies will reach net zero far too late. So we must reshape the system. From a climate perspective, once we reach net zero we can travel as much as we like."
