Melody Cheung, 16, St Paul's Secondary School While tourism generates millions of dollars in revenue, many seem to forget the harm it causes. For example, a record 130,000 tourists visit the Forbidden City in Beijing every day, much higher than the ideal capacity of 30,000. The packed crowds, and their litter, may cause serious damage to the ancient structure. Despite the tremendous income the central government earns from allowing so many guests to visit the Forbidden City, no amount of money would be enough to make up for the loss of cultural and historical value. It's the same with human disturbance of coral reefs. The US Coral Reef Task Force identified 'recreational overuse' as one of the six top threats facing America's reefs. In developing countries, the rapid expansion of tourism isn't always accompanied by effective conservation efforts. Once ecosystems or structures are damaged, it will take a lot of time and money to restore them - if they can be repaired at all. Also, travellers can spread infectious diseases around the world. A pandemic could kill millions of people and destroy world economic growth. Then there's global warming. Most tourists travel by air, and planes release huge amounts of carbon dioxide into the atmosphere. This causes the Earth's temperatures and sea levels to rise, posing a serious threat to low-lying areas. So tourism's disadvantages outweigh its benefits. Charmain Li, 18, Imperial College London There's growing awareness nowadays about how tourism can wreck tourist attractions. I believe there are ways to ensure that the economic benefits generated by tourism eclipse the damage caused by the surging number of visitors. Above all, sustainable tourism needs to be promoted. This means meeting all the needs of tourists while making only a small impact on the environment and local culture. This model creates economic benefits for locals - they have jobs and earn an income - without harming a tourist destination. There will be minimal wastage and ecosystems won't be damaged. Tourism is a huge industry in many developing countries. Millions of people rely on tourism for their livelihood. This is especially important at a time when America and many countries in Europe are facing recession. It can even encourage people to set up their own businesses by promoting the unique aspects of their culture, food or merchandise. Tourism also allows interaction between locals and tourists, leading to a better understanding about the cultures of different places. People can learn from one another and promote respect for each other. Hence, sustainable tourism can lead to positive experiences for locals, the tourism industry and the tourists themselves. At the same time, it will generate economic benefits that can overshadow any potential damage caused by the tourism industry.