This is a common and understandable sentiment, but there is no evidence suggesting that it is true. Scientists are clear that human activities in coming months and years are absolutely critical to the future of the climate. We may not be able to stop climate change totally in its tracks—at least not immediately—but human activities are what have caused the warming, and a coordinated human response can have a decisive impact on the future of our climate. The future is in our hands. We must act, with immediacy, courage and vigor.
The fatalistic response is understandable. This grim brand of certainty seems to help some people cope with their terror of climate change. Claiming to know, definitively, the fate of humanity and the world can be a relief against the feelings of being small and afraid. Making claims of certain destruction can provide a feeling of power and omniscience. It also absolves the fatalist of the moral duty to urgently fight back.
Such fatalistic certitude is indefensible because: 1) Our top scientists disagree with it, telling us that what humanity does in the next few years will have a tremendous impact on the future and 2) To claim that something as complex as the fate of humanity and the natural world is sealed is the essence of hubris. We don't have the ability to know, for sure, what will happen in any scenario. There are no prior cases of human-caused climate change to study. We are the test case. This is very frightening information, but it does not lend itself to the conclusion that we are, inevitably, doomed. Furthermore, resigning yourself to "doom," means that you're okay with the prospect of billions of people, including possibly yourself, dying early, painful deaths within this century. It could even mean you’re resigned to the suicide of our species.
The dissemination of this unverifiable argument is highly destructive. It is capable of immobilizing large groups of people, who may otherwise be working to save civilization. The idea that our fate is sealed—that destruction is unavoidable—is a self-fulfilling prophesy: If we collectively resign ourselves to despair and do not mobilize, we are surely doomed. Imagine if the sentiment in the US after Pearl Harbor had been, “We can never beat the Axis powers, so let’s just allow the inevitable to happen and surrender to them.” We could have never mobilized. Despair is not a moral option in times of great crisis. We have a moral duty to muster our courage and give this fight our all.