Current human society is completely and utterly buggered.
We are about to (or have already) hit Peak Oil production for planet Earth; crude oil has been the catalyst for mankind's explosive expansion in every field; science, art, medicine, culture, population. For the past 60 years we have been blessed with fairly low prices for nearly everything; food, water, transportation, medicine, education, information, all due to the presence of easy to acquire crude oil.
From now on till whenever the oil does truly run out, we will find it more and more difficult to get at the oil. If we had constant consumption (as of levels today), we would have about 10 years to plan for when the oil becomes expensive to drill for, plan accordingly and avert the first disaster; but consumption is not constant, as China, India, Russia, Eastern Europe and pretty much every country in the world is demanding more oil to fuel their economic expansions.
We could be looking at the pinch point in the next 4 or 5 years with no preparation for it.
This sudden shortage of the only thing that keeps our society heated, fed, clothed, moving and functioning could be our collective downfall. Systems that we have grown to rely on since the 1970's will choke, splutter and eventually die because of a lack of crude oil. Food production, which requires crude oil based fertilisers and pesticides, diesel to ship and cool, plastics to package and transport, will plummet. Only the rich or self sufficient will be able to compensate for this, with an inevitable drop in the world population; in the short term this will be in poor areas of the world, but in the medium term the hardest hit will be first world nations with high density population centres; London, Paris, New York, Moscow, anywhere urban locked will be next to impossible to feed, and eventually, get clean water to.
The shortage of crude oil, assuming we survive it intact, will lead to a World War to secure crude oil. The only way that nations will be able to do this is by invading oil producing contries, specifically in the Middle East. America, Russia, China, India, Israel, France, Britain and possibly Iran; we will all be at each others throats to control the oil. Iran is developing nuclear weapons not only to cajole neighbouring nations to succumb, but to have a credible and known retaliation should a power attack; not even Bush would invade a country that has nuclear weapons with no compunction to hand it to terrorists.
With Russia having a non-aggression pact with Iran (and probably with China as well), and NATO still being in force, we would be looking at a WW3 nuke fest, in which case the cities mentioned above would cease to be.
If we manage to pull through these with diplomacy and no bloodshed, we have the whirlwind to reap we sowed back in the Industrial Revolution; global warming, from which we have no escape from or way to counteract.
The Kyoto Protocol, enacted as of 2004 (IIRC), was 30 years too late. The conversion to cleaner fuels, more economical transportation, and greater efficiency is also 30 years too late. We cannot expect the planet to be able to absorb nearly 250 years of increased and ever increasing CO2 emmissions without it being adversely affected. Cutting the methods of CO2 removal (chopping the rainforests down, reducing habitats, increasing intensive farming) is like taking a hospital ward, taking some of the ward space for offices every few weeks whilst asking them to take more patients; eventually you can't fit any more in, no matter how small you make the beds, how you stack the patients, how you rotate them, it will seize up. Why would it be any different for our climate and atmosphere?
These events could all be the wrong way round; everyone could go to war to secure as much oil as possible before the crash. Planet Earth could decide it's had enough and try to balance itself by removing us.
According to many scientists, we are over due an asteroid hit, a supervolcano eruption, natural climate change or a massive outbreak of a deadly virus/bacteria.
Either way, I think the next 5 to 20 years will be some of the most important and deadly years for the human race (depending which bit gets us).
We could be staring at the biggest mass extinction in this planet's history; directed, enacted and executed by the species soon to be extinct.
Or, we could be looking at the biggest opportunity to build mankind into something more than we have already achieved, but achieve our new strides into science, medicine, knowledge, enlightenment and life with a sustainable, inclusive and tolerant society.
I'm feverantly hoping for the latter, yet seeing the former as the odds on favourite.
