Indeed, it does seem that the Earth will run out of oil, natural gas and coal much more quickly than was, originally, anticipated by researchers keeping track of overall expenditure of these resources . At the same time, others warn that any expectation of nuclear power taking over as an effective substitute is both unrealistic and, potentially, ruinous .
On other grounds, ethanol can't work either . Meanwhile, wind, solar and hydro provisions won't be sufficient in and by themselves. In addition, what sort of work will people - the billions making their livings in industries related to airlines, cruise lines, mechanized workshops and factories producing oil based products such as plastic items and fertilizers -- do since their jobs are dependent on the use of huge amounts of petroleum? Yes, what will they all do once it all but disappears?
In the same vein, our high rate of agricultural yield, medical care, transportation of the basic goods needed to sustain life, home heating and cooling, travel related to school and work, as well as so much more constituting "our way of life" are all, directly and indirectly, reliant on fossil fuels. Likewise, many diverse industries require huge energy inputs for the production of a voluminous and diverse assortment of wares on which most people have come to depend. Therefore, it is ill-fated that most of our electricity derives from coal, gas and oil. For example, 68 % of the electricity in the US is provided by these power sources  and nothing yet found by scientists can adequately replace them without disastrous results.
If we had small self-sustaining communities across the world fulfilling most basic needs locally, our dependence on fossil fuels would not be such a daunting issue. Needed adjustment (weaning away from our heavy addiction) could transpire more easily. However, our complex lifestyles and ever booming population necessitate increasing amounts of energy to be sustained.
Especially this is so with the ways that our capitalistic system and transnational economics are configured so as to obtain cheap raw materials in one location, low wage labor in a second and high paying purchasers in a third with the goal in mind to always provide ever more consumables to ensure ever great profit for corporate heads and stock holders. In other words, our customs and standards of living are, literally, bringing us ever closer to a pending downfall.
In this vein, it will, likely, lead to the most rapacious members of humankind (the ones who've always garnered the most power, resources and money for themselves) making out just fine, as always. Their kind -- comprising of corporate moguls, certain government leaders appropriating benefits from war mongering activities and others of their ilk -- nearly always find a way to flourish in spite of surrounding adversity.
From an evolutionary standpoint, this sort of outcome always is the case regardless of whether we find this pattern morally repugnant and outrageous or not. Survival of the fittest always has meant that those most successful at taking "the lion's share" most often thrive regardless of whatever happens to everything and everyone else.
Yet despite the many severe daunting problems that the rest of us will, obviously, face due to the decreasing supply of fossil fuels, the benefits from running out of them, certainly, could include curtailment of global warming effects. All the same, it does not seem that their disappearance will provide any welcomed panacea for humanity's collective and looming woes .
In part, this is because many diverse environments across the globe are staggering under the influence of weather changes already having taken place from the rising heat. Our species and other ones are already at risk from the nearly universal threat of drought, crop reduction , ever more powerful hurricanes, wild floods, spreading fires, vastly expanding desert regions, rising oceans and other awful impacts. Meanwhile, they're slated to get worse.
Even the outcomes that are not so thoroughly daunting are bad. As Jean-Louis Robert Turcot, a naturalist in Canada, notes, "In terms of the global warming scenarios that are becoming more and more evident as time goes on, I witnessed a small part of it just yesterday in a remote fishing lake which I, occasionally, visit. The Pine Beetle [Dendroctonus ponderosae], which is usually controlled by spells of cold winter weather, are devastating forests of British Columbia and about twenty-five percent of the trees that line the lake are now red, killed by the insect infestation, with predictions of a ninety percent kill ratio. I felt for the time in my heart that nature was truly being affected, even though these trees were far removed from humanity and I did feel a moment of deep sadness..."
For example, Eurasian Watermilfoil (Myriophyllum spicatum), a non-indigenous plant life with no easy local means for curtailment, thrives in acidic, carbon rich waterways (such as US lakes have become due to their containing acid rain and serving as carbon sinks). With such favorable growth conditions provided, it is, literally, choking the life out of many water systems across America.
Combined with further negatives, such as higher water temperatures and other factors, many aquatic species are shrinking in numbers or altogether perishing. In short, the noxious Milfoil, co-joined with other impingements, is destroying much submerged life on which many other life forms depend. Hence, whole interactive systems are vanishing underwater AND around shores. Moreover, further organisms, ones reliant on the shore life for their sustenance, are similarly being decimated and so on down the line.