I think it would take an additional catastrophe of some sort on top of Scenario #1 to launch us into Scenario #2.
...like peak oil (that according to professional/government/national security bodies all around the globe - we are experiencing right now, since 2004, a "plateau" of oil extraction, not exactly a sharp peak), that will send oil prices sky high, disrupting everything, but most crucially, global high-yield farming (strictly depending on affordable oil AND affordable fertilizers (also past their peak production - phosphorus), AND they have to be shipped globally = oil-dependent again), sending food prices sky-high and sending unemployment sky-high (our western economies are linked 1:1 with the availability of CHEAP oil, and there's NO WAY we could get off oil-dependant economy in the next 20 years, trust me, before I started to educate myself in our current dire economic situation, I was very much into renewables/free energy sources, and there's simply no alternative in sight to cheap oil, not even nearly in our sight, and much less so in the very much disrupted/broken economy).
Like world wide monetary systems being a giant ponzi schemes, depending on an exponential growth of global economy to even kept functioning? Alas, facing hard limits to grow further (re: paragraph above), thus inevitably collapsing (as any Ponzi scheme, that could not grow anymore).
Like Baby-Boomers beginning to retire, and starting selling their accumulated enormous paper "wealth" en masse on the stock market, to pay their monthly bills/retirements, thus sending stocks down, thus forcing them to sell more each month, to pay their monthly bills, thus sending stocks even further down?
Like the enormity of the total (sovereign, institutional, personal) debt, burdening the global economy, that has to be serviced - by borrowing MORE money from central banks into existence? Like the fact that delta debt/delta GDP ratio is going down linearly (currently, delta GDP is negative, so the ratio itself is negative as well, meaning that every dollar borrowed into existence actually DIMINISHES the money supply in the economy, but why bother, "leaders", huh?)
Like the size of derivatives markets being AN ORDER OF MAGNITUDE BIGGER (that is, estimated about 20 times, AFAIR), than the size of global REAL economy, and this enormous casino wobbling above the heads of all of us, if (no, sorry: WHEN) burst, will came down crushing every bit of REAL economy in its path...
Shall I continue
All these above are not figures of speech or more/less relevant memes, these are FACTS, and these are only the most important ones I have, and best backed in hard numbers.
Global warming is small potatoes, comparing to these ticking timebombs. But at least people are talking about it for quite a while now.
What about all of these above? It is not even on any public discussion agenda! As such, there's no way anyone will ACT on them, before too late (BTW, another curious fact, with regards of ACTING upon the core problem of our current, flawed-by-design monetary/banking system: every US President who attempted and/or succeeded to take the power to issue US dollar back from the hands of central bankers into the hands of Congress (as the US Constitution warrants, by the way...) was either assassinated, or attempted to. Surely, a coincidence!)
I never thought I will be trying to scare people with a global financial armaggeddon, that will most likely transform into some kind of a REAL global armaggeddon, but here I am, just quoting the facts collected by smarter than me, more in the know in every of these issues, that when viewed together, are downright frightening. And there's no magic technology to the rescue.
In short, we are heading towards the cliff at ever increasing pace, and the real cause for it is our fiat monetary/fractional reserve banking systems, that REQUIRE exponential growth to prevent them from collapsing. Did anyone said "a bubble"? We are living in an enormous, monetary bubble, started a good while ago - when money started to be BORROWED into existence, and then leveraged a hundred times, via fractional reserve banking - yet again, as an interest-bearing debt. And our planet is finite. It cannot stand the chance against exponential growth. Or, shall I rather say, exponential growth cannot stand a chance against our ULTIMATELY FINITE RESOURCES... So sooner or later, the collapse of such a system, based on a giant Ponzi scheme, is inevitable. And the facts seem to be pointing out that writing is on the wall.
I can only hope our financial "engineers" will be able to buy me enough time to develop enough resilliance in my life for inevitable catastrophe, since I am very late to the game, and woefully unprepared at the moment - but trying hard to change that ASAP. The tragedy is, they are not trained engineers, these chaps, only economists, and worse still, working hand in hand with complete muppets, ie politics/policymakers. If they were engineers indeed, they would NEVER design a system which requires an exponential growth, just to keep it functioning - have you ever seen a car, that would require you to put, say, 7% more gasoline in every year, just to keep it running? Just for laughs, it would meant, that after just 10 years, your MPG would HALVED, and god forbid 20 years - it would be a QUARTER of the original. And it would be by design so, regardless of any efforts from you to drive economically etc

. Just like our economy is DOUBLING roughly every 10 years, at the "stable" economic growth rate of 7%.
The power of exponential functions is very easy to underestimate, but it is crucial to understand why our current civilisation is at the brink of a total collapse.
...and a very Merry Christmas, to you, of course

. Pray to God I am an idiot scaremonger. But better do not bet your life on this assumption, not trying to boast myself nor anything like that

, but my IQ according to official tests is quite high in the general population, and also I tend to be quite a critical thinker... That is just that... We are deeper in shit, that anyone would like to admit, IMHO, and it is just hard to believe that our (mostly) comfortable and secure lives, will most likely look extremely different, in quite a short time from now...
Best Regards,