Basically, the reason most of the dinosaurs went extinct is because they were foolish and short-sighted and didn't bother to develop a serious space program so they could detect, track, and then intercept inbound asteroids. They lived at a time when there were surely more asteroids hitting the Earth than now (the system was younger, so there was more debris flying around), so they surely had more warning than we do: craters, smaller impacts, etc. They ignored all this, so when a really big asteroid came along, they had no way of redirecting it, or even detecting it beforehand.
We're not doing much better.
We can detect some asteroids, but are we able to intercept and redirect them? No, because we haven't bothered investing much money in a program to develop that capability. Yet we've had plenty of impacts and near-misses. One hit in Russia a few years ago, injuring 1000 people. One flies by pretty frequently, and I think one is supposed to come extremely close this month. Where's the program to intercept these things well ahead of time and redirect them?
Climate change isn't that different, except that it isn't just some natural occurrence, it's something we're mostly doing by ourselves. So we're studying it some, we've made predictions about what the effects will be based on evidence from earlier times, yet we absolutely refuse to make any real changes to attempt to avoid this fate.
In short, we really aren't much smarter than the dinosaurs.