Even ignoring the CO2 produced by flying, what evidence is there that enviro-tourism itself reduces CO2 emissions?
I admittedly lack evidence on the enviro-tourism aspect, but it seems logical that tourists from heavily industrialized 3rd world countries return with some desire to improve their home environment.
"Coral reefs are some of the most diverse and valuable ecosystems on Earth. Coral reefs support more species per unit area than any other marine environment, including about 4,000 species of fish, 800 species of hard corals and hundreds of other species. Scientists estimate that there may be another 1 to 8 million undiscovered species of organisms living in and around reefs (Reaka-Kudla, 1997). This biodiversity is considered key to finding new medicines for the 21st century. Many drugs are now being developed from coral reef animals and plants as possible cures for cancer, arthritis, human bacterial infections, viruses, and other diseases.
Storehouses of immense biological wealth, reefs also provide economic and environmental services to millions of people. Coral reefs may provide goods and services worth $375 billion each year. This is an amazing figure for an environment that covers less than 1 percent of the Earth’s surface (Costanza et al., 1997)."
http://oceanservice.noaa.gov/education/kits/corals/coral07_i...
"The IPCC has estimated that aviation is responsible for around 3.5% of anthropogenic climate change." [https://en.wikipedia.org/wiki/Environmental_impact_of_aviati...]
> “This isn’t just an environmental issue. The Great Barrier Reef is one of Australia’s greatest economic assets. It’s responsible for bringing in more than $7 billion each year to our economy, while also supporting the livelihoods of around 70,000 people.”
The irony is that in order for these tourists to visit, they have to fly overseas in planes creating significant carbon emissions.