Even people who pay attention to climate change tend to think in terrestrial terms: aridity, extreme weather, crop management changes, and effects of sea level rise on property. But most of our planet is covered in water, and what happens in the oceans matters.
Here is a meta-analysis of studies on biological changes in response to various factors associated with global warming, but not limited to temperature increase. A repeated theme is how there is little data on various factors and what coverage there is tends to be concentrated in studies of the North Atlantic, but even given how little attention has been applied to looking at these things, there is a burgeoning laundry list of how species are changing where they live, when they do things, and how well they live given the change in particular factors in their environment.
We have instituted vast changes in the conditions of life for the majority of the planet and have failed to pay enough attention to even know exactly how much impact that is going to have. We landlubbers tend to take the oceans for granted, even though 50 to 70% of the oxygen we breathe comes from oceanic phytoplankton. If we overturn the ecology of the oceans and mess up the phytoplankton among other biota, though, I expect we will have a geologically brief collective moment to reflect on that mistake before going the way of the dodo. The analysis shows that change is happening, that responses are occurring, and we have essentially no clue what the total risk involved is.
Update: See also this article on rising heat in the oceans from The Guardian.