Because it is a current event and it gives a lot of impact, and now that everyone is exposed to a higher temperature until the feeling is different from the past that once every year. The cause of the global warming.
Because the current And made known to affect many, and now that everyone is exposed to higher temperatures every year and feel very different from the past. This cause of global warming itself.
Because of current events. And know how to affect a lot of things and now that everyone can touch is a higher temperature, so feel different from every year ever since. This causes from global warming.