I don't think so. It's probably a real threat to human survival, but most people lack the perspective to recognize that. Humans are great at denial.
I guess not even the majority see climate change as the biggest threat, there are people who see an equal threat solely in vaccinations or diversity. For others it might be immigration, war or economy.
Maybe the difference is that we invented devices and services to easily share our fears and communicate them to others. 15 years ago most people weren't equipped with the tools to keep a constant stream of new information about "their" biggest fear alive. They might have read a book about it, some articles on the internet, or a documentation on TV. But getting that information needed some effort. Like getting some screen time on the family PC (which took minutes to boot up), going to the book store, or renting a DVD. It was something that you did maybe twice a month. Today everyone can open their favourite apps at any time and get new content about "their" fear multiple times a day. The social media platforms even keep suggesting those new pieces of information, so you see them also if your intention was only to watch some cat videos to calm down before going to bed.