Study predicts imminent irreversible planetary collapse

Post by ktizo » Tue, Jun 12, 2012, 1:08 AM UTC

apsec112 wrote: post #44

ktizo wrote: post #38

Earlier quoted context omitted.

I thought the claim was that the earth's environment is subject to critical transitions, that critical transitions are by their very nature highly disruptive on all levels of a system, and that if you statistically map the environment then it looks strongly as though we look like we are approaching another one rather quickly. The thing is, if we are approaching a critical transition then it is very hard to say what t…

"Transitions" is way too vague to mean anything. What will "transition"? The climate? Another climate transition on the order of the most recent interglacial beginning seems reasonable (+3-5 C over centuries), but if that's what "critical transition" means, we've been through dozens over the last million years and are none the worse for wear. (At least if you just look at species count.) What would the actual negativ…

Post by anthonyb » Tue, Jun 12, 2012, 1:13 AM UTC

apsec112 wrote: post #42

eschulte wrote: post #40

Earlier quoted context omitted.

"the planet’s ecosystems, as we know them, could irreversibly collapse in the proverbial blink of an eye" seems like a fairly straightforward clearcut negative consequence. They're worried that ecosystems (those networks of interacting species) will collapse (meaning the ecosystem dynamics change and the vast majority of the species who rely on and compose the ecosystem go extinct).

That seems like obvious nonsense - eg. mile-wide asteroid impacts, which are much larger in terms of energy release than all nuclear arsenals combined, don't cause mass extinctions. But it at least gets credit for being a specific claim. Just saying "collapse" is vague, and could arguably apply to just about anything.

  BOX 1: Past planetary-scale critical transitions and state shifts

  Last glacial–interglacial transition18,24. The critical transition was a
  rapid warm–cold–warm fluctuation in climate between 14,300 and
  11,000 yr ago, and the most pronounced biotic changes occurred
  between 12,900 and 11,300 yr ago24,27,30,54.

  The major biotic changes were the extinction of about half of the
  species of large-bodied mammals, several species of large birds and
  reptiles, and a few species of small animals30; a significant decrease in
  local and regional biodiversity as geographic ranges shifted
  individualistically, which also resulted in novel species
  assemblages37,49,53,54; and a global increase in human biomass and
  spread of humans to all continents27.

  The pre-transition global state was a glacial stage that lasted about
  100,000 yr and the post-transition global state is an interglacial that
  Earth has been in for approximately 11,000 yr. The global forcings
  were orbitally induced, cyclic variations in solar insolation that caused
  rapid global warming. Direct and indirect of effects of humans
  probably contributed to extinctions of megafauna and subsequent
  ecological restructuring.

Post by ceol » Tue, Jun 12, 2012, 1:23 AM UTC

jcdreads wrote: post #52

droithomme wrote: post #48

Earlier quoted context omitted.

The article then states that "This study concludes we better not exceed the 50 per cent mark of wholesale transformation of Earth’s surface or we won’t be able to delay, never mind avert, a planetary collapse", as if that is a fact, and then claims that "We’ve already reached the 43 per cent mark through our conversion of landscapes into agricultural and urban areas" (maybe that is so for their definition). And then…

The authors do not say "drastically lower our population very quickly" anywhere in the paper. The closest I can see that they come to saying this is in the conclusion, where they talk about, "reducing world population growth and per capita resource consumption" (among other things) as being "vital". Please save your accusations of irrational, hysterical agendas for them that advocates hysteria and the abandonment of…

Post by jcdreads » Tue, Jun 12, 2012, 1:32 AM UTC

roc wrote: post #29

excuse-me wrote: post #23

The planet is fine it's not going to collapse. A few species on a thin smear of biosphere on the outside of the planet might be in trouble - but the planet is perfectly safe until the sun expands.

Why stop there then? If you've decided that 'safe' indicates the continuation of the mass that comprises our planet, and not the particular, temporarily-compatible, form it takes today, then why even worry about the expansion of the sun? Or a collision which may shatter it? In how many ways is an asteroid cloud meaningfully less 'safe' than a single barren rock of comparable mass? I mean, you've already dispensed wit…

Post by jcdreads » Tue, Jun 12, 2012, 1:41 AM UTC

droithomme wrote: post #56

jcdreads wrote: post #52

Earlier quoted context omitted.

The authors do not say "drastically lower our population very quickly" anywhere in the paper. The closest I can see that they come to saying this is in the conclusion, where they talk about, "reducing world population growth and per capita resource consumption" (among other things) as being "vital". Please save your accusations of irrational, hysterical agendas for them that advocates hysteria and the abandonment of…

I pasted the quote directly from the article. Thank you for the reactionary downvotes.