system
Given the following post, respond as if you're commenting on Reddit:
human
I think civilization as we know it will end during my life time. CMV

To give an idea of what "during my life time" is, I am almost 30 years old. I really hope that I am wrong about some of this stuff, because the future is looking really dark in a lot of ways, so please CMV.

  The biggest threat I think humanity as a whole faces right now is global warming. It is a scientific consensus that global warming is happening and that the consequences could be disastrous. Recently, even the more conservative estimates are on the quite disastrous side. Humanity MAY have still have a window to stop greenhouse gas emissions and escape the worst, but I think this is unlikely. Recent signals of feedback loops being triggered (arctic ice, tundra melt, methane emissions from the ocean, Amazon going from carbon sink to carbon source) indicate that we are probably not going to be able to reverse this. This leads to a few reasons why civilization as we know it cannot continue:

1. Pollution is killing off species and warming is destroying habitats. If enough species die, we could see a mass extinction event in a short time with a quick ecological collapse.

2. Disasters caused by global warming have already displaced millions of people around the globe. Also, events such as droughts starve millions. If these kinds of things continue to worsen, the global economy won't be able to stand in the face of the disruption.

3. Food resources will grow scarcer from the above stated reasons. Ironically, oil is also becoming more scarce (this is a good thing for reducing emissions, but probably too late for that). As resources dwindle, we are going to see war increase as a scramble to grab the last remaining energy and food supplies. You could argue that civilization will continue for the victors, but certainly not for large parts of the world population.

4. Arguably none of the above would have happened if we hadn't expanded human population during the 20th century so rapidly. We are probably way past the long-term carrying capacity for the Earth and will see it corrected shortly. Again, you could argue that civilization will continue for the survivors, but I doubt it will look much like it does now.

I guess I could word it a little differently. I think large amounts of people are going to die during this century, and whatever is left over will inevitably be more of a rebuilding than a continuation of civilization. CMV!
gpt
No prediction of doom for humanity has ever come true even once in human history, and there have been a LOT of them.

Global warming science says that the planet is warming, sea levels are rising, and it is our fault. There is nothing there about not being able to stop it; there is not even anything there about not being able to deal with rising sea levels.

I agree with you that it will probably end up killing many, many people, but it won't be anywhere near the end of civilization. If it kills even as many people proportionally as the definitely-not-world-ending Spanish Flu I'd be surprised, but even if it kills as many people as the still-definitely-not-world-ending Black Plague civilization as a whole would be fine.