"Adds heat" is a woefully inadequate simplification of whether or not it's an issue to be concerned with. When temperature goes up, other things change as a result of the relevant phsyics. For instance, the evap/precip cycle accelerates, carrying more warm air and moisture up, and more cool air and moisture down. CO2 in the upper atmosphere reduces radiation by a factor, but more heat up there, more often, increases radiation. More CO2 almost universally implies conditions better for plants. More and healthier plants means more of all sorts of things and less of others.
Dire predictions: Warming moves the zone(s) within which plants and animals flourish north. There's plenty of room to go, a great deal of northern area is frozen wasteland at this point. More CO2 is good for plants. People might have to move. They do that all the tiime. Coastlines may change and infrastructure may need to maintained, adapted, moved or replaced. That happens all the time. Currently estimated timescale for sea level changes: inches per year. Totally yawn-worthy.
In short, the issue is complex beyond any possible "on noes, warming" assessment -- hysteria is entirely uncalled for.
Science is a method. When facing something new, it involves formulating a hypothesis, testing that to validate or disprove it, and then drawing conclusions. We have not seen and do not know what happens when CO2 increases by large amounts due to our production of it. In the historical record, CO2 increases trail warming, not lead it -- which is another way of saying that historically speaking, CO2 increases herald cooling, so that is not any kind of adequate confirmation of the idea that human-caused CO2 increases will lead to significant climactic warming. Doesn't mean it won't -- it just means that this is a new thing and that drawing conclusions either requires flawless modeling that takes everything significant to the process into account (which we don't have... not only in re natural processes, but in re unanticipated technology), or actually seeing what happens. Without one of those - which again, we don't have -- it's not settled science. It is unvalidated hypothesis.
o Yes, we should be trying to figure this out.
o No, we have not figured it out.
When will we know when we have figured this out? When we have a model that accurately predicts climate change as known to have occurred in the historical record.
PS: coral does not "die when you touch it." I have multiple coral reef tanks. I touch my corals (hard ones and soft ones) all the time to move them around, frag (subdivide and transplant) them, brush them when I'm reaching for something else. I cut colonies of soft corals with a razor in order to divide them into more than one instance and place them in multiple places and/or share them with other coral reef owners. Certainly doesn't kill them (doesn't even seem to hurt them.) For hard corals, you break them into separate instances (frag them) with tools that are basically smallish hammers and chisels. You even do this out of the water. Again, doesn't kill them. They don't die because they were bothered or touched. I've never, ever seen that happen. Some of them don't react at all or very much, but the most I've ever seen them do is pull away or retract, dependably to return to their original extension and condition within minutes of the disturbance that caused it ending. Fish touch them all the time as well. Doesn't hurt a thing.
The things that I have seen be directly and immediately detrimental to corals are Ph changes, temperature changes, salinity changes, very large and sudden changes in lighting, and the actions they engage WRT each other (chemical warfare among corals has to be seen to be believed. They are nasty to each other at times.)
Climate change panic bores me. Climate change dismissal bores me. But, like a lot of other induced hysteria, it's a major component of pop culture and the media's slavish devotion to fanning same, so I have to actually work to avoid both. :)