My only problem with the anthropomorphic causes is that the argument is a bit of a red herring. It simply doesn't matter if humans are the cause. What matters is that humans are the only agents capable of affecting change on this front.

Global climate change is well documented. The movement of tectonic plates alone (among a wealth of contributing factors) is enough to push the ocean currents all over the place, which has dramatic effects on world climate. The average yearly temperature has been both much higher and also much lower than current average yearly temperatures.

The Earth is in a period between ice ages. The Earth has had hothouse conditions before.

The sun's evolution as a main sequence star will cause it to gradually deliver more and more light to the Earth. This will certainly boil the oceans in due time (at least 100 million years or so from now).

The climate changes. Whether / how much it has been caused by people is simply irrelevant. The facts are that climate changes, that affects us, and we are the only ones capable of doing anything about it.

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The current trend in the data is that of warming. That will have a profound effect on the shape of the coastlines of the world. As far as direct human impact goes, this is pretty much the extent of it (as I understand). The changing salinity and temperature of the oceans will dramatically alter all of those aquatic biomes. The warming temperatures will change migratory patterns and drive new pressures for the species of the world. This has happened many times before. This will only indirectly affect humans.

Humans are the single most adapting species on the planet. Humans live in deserts of the Sahara and the deserts of Antarctica. From the jungles of the Congo to the vast sprawling metropolitan cities of the world. Humanity is absolutely not threatened (on a catastrophic or extinction level) by global climate change. Any doomsayers who hint at this are being equally pigheaded about the data as the climate change deniers.

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The erosion of arable land is going to impact humans more profoundly than climate change.