阅读下列短文，根据短文内容填空。在未给提示词的空白处仅填写1个恰当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

When （1） （travel）, we engage with cultures and experiences. However, according to a report by the World Wildlife Fund, tourists （2） （leave）over 1.3 billion tons of food waste last year, （3） accounted for about 8% of the total global gas release in 2024. To reduce our impact, we can take simple steps: empty the fridge before heading out, and choose sustainable dining options. These efforts help us travel more responsibly. After all, exploring the world shouldn’t come （4） the planet’s expense.