Don't believe all you hear
Peak oil is coming, they say. One day soon there will be a year when more oil (or fossil fuel in general) is used than ever before or ever after. No doubt. Most things peak, after all. But does it have any significance, beyond the academic? Does the coming of peak oil mean we are safe from armageddon? If not, why are they telling you?
The answer may be about as sinister as it could be. Imagine, as an analogy, that you are employed by some UN refugee support agency to visit the site where, it is said, local civilians are being rounded up and shot en masse by the current bloody military regime in power in the area. When you arrive, you find the situation exactly as stated. The officer in charge of massacre greets you cordially, and you remonstrate with him, saying that his actions are unethical. He assures you that you need not worry unduly. He admits that, viewed in retrospect, starting the massacre might not have been morally defensible, but he assures you that little more harm will come to the local population, because the soldiers are about to run out of ammunition anyway. So there is no need for any inconvenient change of plan, and no one should bother them with undue ethical considerations.
Of course, the massacre of a few humans bears no comparison in terms of degree with the destruction of much of the life on Earth, but you get the general idea. The Peak Oil types are relying on the same old "running out ammunition" argument as the unspecified regime in the above example. Their interest is, I suggest, not to alert us to a mythical threat at some time future, but instead to avoid their responsibility for a real crisis already in progress. They also hope to position themselves as best they can for the future by looking like the sort of people who care about the future.
It takes little research for even the stupidest of us to satisfy ourselves that, while fossil fuels will undoubtedly get slightly more difficult to obtain cheaply, the atmosphere's capacity to absorb fossil combustion products will to run out first. In fact, the atmosphere is already effectively full, and the oil wells are nowhere near empty. Reserves now starting to be exploited also produce much more CO2 than previously for the same amount of fuel produced. As oil exploitation becomes more difficult, we must expect that many gallons of oil will be burned to extract each gallon of oil produced, with the carbon thus burned entering the atmosphere ever faster.
If only we could run out of fossil fuels, we would be safe, but unfortunately we cannot.