Transport, accommodation and other tourism activites already account for four to six percent of global greenhouse gas emissions that drive climate change, according to the report, which is due to be released later this year.
But the industry's growth could lead to a 150 percent increase in its carbon dioxide emissions alone in the next 30 years, the UNWTO, UNEP and the World Meteorological Organization (WMO) agencies said.
Just under three-quarters of the carbon dioxide produced by tourism comes for transport — 40 percent from aircraft and 32 percent from cars, while accommodation accounts for an estimated 21 percent, the report said.
Emissions are being driven by the rapid increase in international travel, with about 846 million international trips worldwide last year and growing at an average annual rate of 6.5 percent since 1950, according to the UNWTO.
The number of international trips is expected to nearly double to 1.6 billion by 2020.
The global tourist industry is now worth $880 billion annually, surpassing oil exports, food production or the auto industry, it said.
Travel to and from the poorest countries that rely heavily on tourism represents only a small proportion of trips but they are among the ones most exposed to climate change, Frangialli stressed.
He said that overall efforts in the industry to tackle climate change could also contribute to poverty reduction in such countries.
"Tourism is an important player in both as it represents the main economic driving force for several developing states," Frangialli said.
The Davos meeting is due to set the agenda for a ministerial summit on tourism and climate change in London on November 13.
