If economics took externalities into account then our entire economic order would break down. Thus, it won't happen...until eventually the whole thing stops working.
Externalities have a long history in economics. The concept has always been a somewhat slippery and controversial, but remains an important analytical tool for discussing market failures and government intervention [0]. The prospect of ecological collapse has drawn a lot of attention to the idea of negative externalities, but it's worth mentioning that positive externalities are also important in economic theory. For…
Exponential growth has a tendency to creep up on you, and then all of a sudden things are out of control. Plus, there are the significant lag effects, where we don't feel the effect of today's pollution until much later (which is usually decades later, depending on the nature of it).
People should be panicking about this, but most prefer to just pretend everything is fine or we'll somehow invent some magic technology that will defy the laws of physics.
[1]: https://climate.copernicus.eu/global-temperature-exceeds-2de...