It is sometimes pointed out in climate discussions that the earth has been much warmer at times in the distant past, so why should we be upset about it getting that hot again? Apparently some obvious differences need to be spelled out. (Sigh.) OK, I will give that a shot. These points are why we humans should be worried, not about "the planet", but about our own survival as a civilized race. Read on below the orange heat wave.
The last time the earth was hotter than it is predicted to get this century, genus homo did not exist. Our entire life as a species has been spent in the alternating ice age/interstadial pattern, and our entire civilization has been in this interstadial. (Arguably, we ought to be headed into another ice age but we are making that nearly impossible.)
The inhabitants of the hotter earth were free to migrate to find congenial conditions. They had no jobs or mortgages or obligations holding them. They hadn't built a quadrillion bucks worth of immovable infrastructure in the areas that were then, and will be again, under water. (That figure is pure rhetorical guesswork and quite possibly low.) There were no national boundaries and no immigration laws.
If humans find their habitats becoming unlivable today, they cannot just move. The cooler areas of Earth cannot absorb the population of the subtropics. This will not stop desperate people from trying. There. Will. Be. War. There are already wars over resources. There are already desperate migrants. We are not dealing with them in any way that suggests we could handle a hundredfold or thousandfold more.
Past inhabitants of earth ate what didn't eat them first, best two falls out of three. Today's humans are vastly more numerous and dependent on a relatively few specialized food crops, which will not produce as abundantly in less favorable conditions. Droughts and floods alike cause crop failures. Farm animals make less milk, fewer and smaller eggs, and put on less weight in heat waves. There.Will. Be. Famine.
Our species evolved in the tropics, and so did most of the disease organisms that prey on us. They are spread by insect vectors that need warm temps. Cold winters cut down on bugs, mild ones produce pest swarms the following year. No freezing at all means year-round disease transmission. There. Will. Be. Pestilence.
The fourth horseman was Death. Tens of thousands have died in heat waves already this century. If we don't act to abate it, following centuries will see us sweltering in temps that haven't been reached since before the dinosaurs ruled. Those that survive, that is. We aren't coldblooded.
Yes, the earth will go on. Something will probably live here. But if we don't want cockroaches to inherit the earth, we need to use our heads and not our habits.