<nitpick>It’s closer to 8 billion than 7.</nitpick>
But what is the mechanism? Is the half-life even less at much higher concentrations? I.e. is it breakdown in the upper atmosphere from solar energy, is it random oxidation in the entire atmosphere? The first is obviously scales linearly, the latter, faster. Would the resulting increase in CO2 cause a burst of plant growth or plankton growth? Etc.
My argument is that the subtle and third-order effects may be more significant than any computer model predicts. The obvious point is, though, that there’s only one way to find out and the best option is to avoid finding out if we possibly can…
Peak oil was based on the existing known oil reserves and rate of consumption. We’d have to find a new Saudi Arabia every 20(?) years or less to keep up with accelerating demand; there just aren’t too many places left to be found like Saudi Arabia, or North Sea, or Gulf of Mexico. But wait - there is one - the giant shale oils of central North America. For decades, the cost and complexity of recovering that oil was simply too much.
But in 2007, if anyone remembers, gas was pushing $5 and sometimes $6 in the Land of The Free. ($1.50C a litre here in Canada). Entrepreneurs meanwhile figured out how to frack the oil out of the shale of the Dakotas, Montana, Wyoming, etc. So first the world economy collapsed and the demand pressure on oil dropped dramatically. Then frack oil flooded the market. The USA became the largest oil producer in the world again. Gas dropped from $5 a gallon to $2, oil from $100-plus a barrel to $40 and under. So essentially, we did find a new source of oil to put off the supply crunch (“Peak Oil”) for another decade or three…or more.
Killing more than 90% of all humans would take something much much worse than global warming. Something like… a supernova that releases enough cosmic rays to sterilize most of the planet. Or a collision with an asteroid ten times bigger and/or faster than the one which triggered the K/T extinction event. Or maybe a deadly virus (with no cure) which doesn’t show any symptoms until about a month after you’ve already infected everybody around you.
Now, if you combined several small disasters simultaneously, that might do it. For example, 10C increase in global temperature in just one year AND an outbreak of drug-resistant smallpox AND a sudden drop in our oil supply AND a huge scarcity in the ingredients we use in making artificial fertilizer AND a series of sunspots that overload every electrical wire and basically fry all our electronics… put all those things together simultaneously and you could kill maybe 95% of humans. Heck, throw in a nuclear war for good measure and you could get to 99% but that still doesn’t get you to 100% extinction.
I can imagine a scenario where sudden global warming sets in motion a series of disasters, like dominoes. But that assumes that the dominoes are already there, just waiting to be tipped over, and nobody stops the chain reaction. There’s simply no way that any plausible arrangement of those dominoes would get you past 99% killed.
Yes, my though. a 10C rise would mean utter disaster. Whole swaths of the equatorial regions would become uninhabitable. Places in India, Arabia and Africa already hit the 40C and occasionally 50C range. Even those with ocean-moderated climates like Indonesia, they get monsoons. Climate data for Hong Kong, for example, already lists a rainfall in the peak month(s) of over 400 inches. Harvey was a disaster for Houston with over 40 inches in 3 or 4 days. Imagine getting twice that every day for a month… Who knows what 10C would do to the rainfall patterns. (You do realize 10C is 18F? That’s a HUGE increase…)
I would not foresee human extinction, but I see a huge flood of invaders that would make last year’s Syrian refugee invasion in Europe look puny. The west could easily absorb a million or two of new migrants - but not a billion Africans and another billion or two from the India subcontinent, while also dealing with crop failures or major flooding. North America might be luckier - we could conceivably handle the whole population of central America and Mexico, but not if people start coming across the ocean by the containership load. I suspect vicious war would be the next outcome. And where would China or South America go? I don’t think Siberia or the pampas could suddenly be turned into amber fields of grain and fruited plains overnight, even if the climate turned out to be incredibly cooperative. Even North America could lose half its agricultural area…
I see refugee ships being sunk at sea, troops at the borders machine-gunning anyone who approaches, and other tactics that we nowadays could not imagine condoning. then there’s the disruption to supplies. It takes a functioning economy to produce machine gun bullets. Harvey, for example, seems to have shut down half the refining capacity of North America for a week. We would need mines, factories, refineries, and roads that are not washed out to continue running society. I could see many areas of the USA and Canada being written off - too difficult to support the people there. But I still expect several million people in the temperate to arctic zones to survive, albeit at a severely declined level of civilization.
I find it interesting how optimistic so many folks are about warming. Most seem to think we will survive. Even with a large increase in temperature. It is in the future. So the future will solve it or suffer it. Like our massive financial debts. Old infrastructure. The problems of the future, not ours.
I am 60. So not my problems either. But I do come face to face and suffer ignorant folks everyday in all sorts of things. Occasionally I engage with them to ask why they just did what they did. So often their immediate self evident ignorance, is not their problem. Not their concern. Often not even in their awareness. Just everyone elses problem. And too often my problem.
Things go extinct all the time. From less than large changes. So will we. But it will be suicide. As we will likely be at least dimly aware.
Species go extinct with regularity. Humans (or our ancestors) have faced near-extinction bottlenecks in the past, but that doesn’t mean we are destined to survive all catastrophes.
What makes us, perhaps, unique is our ability to anticipate and respond to catastrophic change. Most of the world is now trying to do so. Even the US has made major strides in the last decade. Will this continue? That’s an IMHO/Great Debates thread, feel free to go there (I’m sure several exist).
I also don’t think anyone is sure exactly how climate change, perhaps including the release of methane hydrates, is going to affect the planet. What if (ignoring the rest of the world) the result is megahurricanes devastating the US east coast, megadrought killing the west, megatornadoes ripping through the plains? Maybe United Statesians will be running for the comparative climate calm of Mexico and Canada.
Exactly. I’ve lived once upon a time where the temperature in northern Canada hit -40 during a cold spell and stayed there for weeks. (Go ahead, figure out if that’s Celsius or Fahrenheit). Given a temperate climate - a longer growing season - a place like that could probably support its modest population. A sudden huge increase in temperature and massive nutrients flowing into the ocean would probably result in a surge of fish population, meaning the inhabitants of the Northwest territories, Nunavut, Alaska and Greenland would be able to survive much like traditional days, by fishing - but for most of the year, not just the summer. Farmers in Tibet or Mongolia might enjoy the new climate too, even if the other side of the Himalayas was getting several times the current rainfall.
Humans are an opportunistic adaptable predator. We can eat a wide variety of wildlife, if motivated. As the ecology adapted to the new normal, humans would move in again with the smarts to pick off the tastiest bits.
Not optimistic. Just realistic. The idea that a little bit of temperature change will be enough to kill off every single human being across every area of Earth while they are putting in their best effort to survive is–frankly–deeply stupid.
As mentioned before, killing off 99 percent of humans would leave behind 70 million (actually 75 million.) Killing off 99.999 percent would leave behind 75,000, which is small, but still 5 or 10 times the human population during a bottleneck around 70,000 years ago.
A cosmopolitan weed species is very hard to wipe out.
From Peter Sandman, risk communication consultant.
Perceived risk = hazard + outrage. The hazard is high, but the outrage is low. Practically nothing can make people afraid of temperature increases, especially something small like 2 degrees Celsius. The risk is simply not upsetting except to experts who have a clear idea of what could happen.
What happened when the clathrates and permafrost melted in previous interglacials?
Glad this wasn’t widely reported like the “on-coming ice-age crap” in the 70s that got a over-reported and mis-reported and gets brought up today all the time.
From the link here - Climate Change Indicators: Atmospheric Concentrations of Greenhouse Gases | US EPA
it appears that the increase in tempertaures released methane at a rate where the reaction of methane with atmospheric hydroxyl keep concentrations from spiking.
The question is, what happens if heating spikes sufficiently fast to drive huge amounts of methane into the atmosphere? We’re reaching new highs in temperature, new lows in ocean acidity and we’re gleefully stomping forward into uncharted methane peaks.
Hold up - that link is CO[sub]2[/sub].
Here’s the methane one : Climate Change Indicators: Atmospheric Concentrations of Greenhouse Gases | US EPA
ETA : Can’t make the link go to the proper chart. If you look at the bottom of the page you’ll see several different view. Methane is down there as figure 2
Agree completely. But …
Our nearly 8 billion people are dependent on our advanced technological economy. If we changed nothing about the planet at all, but merely waved a magic wand tomorrow and 30% of the populace instantly & uniformly vanished without a trace, the resulting shock to the economic system would be profound. Perhaps enough to start a chain reaction collapse back to the 1800s or earlier.
That is, back to a time when the carrying capacity of Earth was larger than today, but the carrying capacity of the human economy was far less.
If we do, for whatever reason, quickly (on a human societal timescale) find ourselves with a population bigger than our economy can support, that will begin a self-reinforcing contraction. Accompanied by mass migrations and mass violence. An overshoot to the downside is all but guaranteed.
Would that make humans extinct? Not even close.
Could large-scale disruptions to the technological economy set off a rapid self-reinforcing downward spiral of human disaster? IMO it has a pretty high likelihood of happening someday for some reason unless we start designing and paying for a lot more resilience in our systems.
Will 10C of global warming by 2026 be that reason? No way.
The text toward the bottom suggests that water vapour is a greenhouse gas with a positive feedback loop. However, I would think that yes, while water vapour mitigates temperature swings from night to day, the high albedo of clouds will reflect sunlight and actually lower the surface temperature.
Pretty much what the IPCCsays
That appears to be a huge spike!
And our use of tools and control over technology.
The answer is given in posts #32 and #33. Again and again, when discussing anthropogenic climate change it always comes down to the question of the extraordinary rate of change – a rate that is one to two orders of magnitude faster than the natural rate of glacial termination. Another way of looking at the same phenomenon: in no interglacial in the past million years has the CO2 level ever exceeded 300 ppm. Today it is 400 ppm and rising fast. This is a fundamentally new phenomenon in the earth’s modern geological history.
So the relevant question is, not what happened to methane releases in previous interglacials, but what happened when large amounts of carbon were released into the atmosphere with the suddenness with which we’re currently doing it. This happened.
That said, the speculation in the OP is a rather alarmist take on a paper that seems to be itself rather hypothetical. What is undoubtedly true is that loss of the majority of polar ice would create a whole new class of positive climate feedbacks that would result in runaway climate change; at the point, current estimates of climate sensitivity (climate response to increased CO2) would probably need to be doubled or tripled. However, we are a long, long way from that possibility. There is ample solid evidence that climate change is a very serious problem – there’s no need for alarmist sensationalism.
You’re missing the point. Look at the CO2 chart for comparison. Those huge spikes at the end are anthropogenic – modern human-caused phenomena. The timeframe of the charts encompasses at least half a dozen interglacials. There is a huge CO2 spike and a huge CH4 spike at only one point – today! As I just said, never in the past million years has CO2 ever exceeded 300 ppm during any interglacial, until we started burning fossil fuels.