Is it possible to avoid a massive die off?

[adam2]

Life can indeed prosper at much higher carbon dioxide levels than those prevailing at present, the dinosaurs did !

Modern civilisation seems unlikely to survive at significantly increased carbon dioxide levels. Sea level rise alone would submerge most major urban centers and much of the most fertile land.

I cant see even the worst climate change killing of the entire human race, some would surely survive in say the Scottish highlands, but most would perish, there is nothing like enough high land to support anything approaching todays population.

[JavaScriptDonkey]

Geologically speaking higher sea levels than today are 'normal'.

However we all seem to agree that we are deep in to overshoot and expect a die off when the oil runs out. What matter then that the coast moves a few miles in land?

[kenneal - lagger]

I would be concerned about pumping huge quantities of sea water into the air in case it came down on land. Certain parts of the world have enough trouble with saline irrigation water without adding saline rain to their problems, Lewis.

[JavaScriptDonkey]

Hmm, just how salty will the sea still be once enough fresh water has ben released to raise it so high I wonder.

[woodburner]

Given that quite a lot of the sea is several miles deep, and we are talking of metres, or maybe tens of metres rise, it will still be pretty salty.

[biffvernon]

We have solid paleoclimate evidence that

over 90% of fossil-forming species died out. We now have the potential to make it closer, or even equal to, 100%.

[JavaScriptDonkey]

We have solid paleoclimate evidence that

over 90% of fossil-forming species died out. We now have the potential to make it closer, or even equal to, 100%.

Over 99% of ALL species have died out Biff - you know that it's an integral part of evolution and is a great indicator of just how much our environment changes over time.

[JavaScriptDonkey]

Given that quite a lot of the sea is several miles deep, and we are talking of metres, or maybe tens of metres rise, it will still be pretty salty.

I like that

[Billhook]

I would be concerned about pumping huge quantities of sea water into the air in case it came down on land. Certain parts of the world have enough trouble with saline irrigation water without adding saline rain to their problems, Lewis.

Kenneal -
Professors Salter and Latham are not looking at pumping huge quantities of sea water into the air - they calculate that around 2,000 vessels lofting a mist of seawater into the lower troposphere should be sufficient to offset committed warming. As a fraction of terrestrial precipitation this isn't a remotely significant amount of rainfall.

They are further aware of the sensitivity of the terrestrial rainfall changes issue, which is one reason why they've been researching the deployment of such vessels to enhance cloud cover over selected sea areas to avoid such changes for the last fifteen years. The planet being about 70% oceans and clouds raining out in about 9 days makes this an eminently feasible goal.

The core issue is whether there is a better option (in terms of affordability x effectiveness x controllability x ecological acceptability) for preventing the onset of intensifying global crop failures during the 2020s, preventing the resulting geopolitical destabilization undermining a global climate treaty, and preventing the destruction of attempts at afforestation for Carbon recovery thereafter.

Cloud Brightening is the most promising option I've seen, but if you come across anything that looks preferable I'd be very interested to learn of it.

Regards,

Lewis

[biffvernon]

Cloud Brightening is the most promising option I've seen,

What does that do for ocean acidification other than allow us to make it even worse!

[Billhook]

Cloud Brightening is the most promising option I've seen,

What does that do for ocean acidification other than allow us to make it even worse!

Biff - your logic in assuming that lofting a mist of seawater to the lower troposphere would worsen ocean acidification - would be hard to follow if that was what you meant.

OTOH, if you meant that Cloud Brightening doesn't resolve ocean acidification I'd well agree, but neither will Emissions Control - which as I pointed out on the previous page offers not the slightest chance of controlling the eight interactive feedbacks that are already accelerating, of which most will add to airborne CO2 concentration, and thus to OA. Nor will EC affect in the slightest our present course towards intensifying global crop failures now indicated for the 2020s.

Cloud Brightening doesn't "allow us to make it [OA] worse" unless a consensus of UN members decided to implement it without also committing to commensurate EC - which is a pretty far fetched possibility given the many states this would injure - In combination with Emissions Control and Carbon Recovery, CB allows us to resolve the AGW problem.

If you'd like to show me how EC + CR can provide a solution without an effective form of Albedo Restoration, I'd be very glad to see it, as it would be substantially easier to achieve.

Regards,

Lewis

[RenewableCandy]

I think Biff's suspicion is that they'll go ahead and do the cloud-brightening

without any other measures

, because they can. My suspicion is, that on this one Biff's right.

[biffvernon]

Er, yes, I thinks that's about it.

If we implement any form of geoengineering that reduces warming by means other than reducing CO2 in the air, then it is likely to make folk even more complacent about emitting more CO2, thus making ocean acidification worse.

The chance of a worldwide agreement to allow geoengineering only on condition of reduce emissions seems remote. Hence I see the only hope in a combination of reduced emissions and carbon capture, BEFORE, we put much effort in things like cloud brightening.

(And since that looks pretty unlikely I don't really see much hope.)

[Billhook]

Biff and Candy -

I take it you get the insufficiency of EC + RC in failing to change the trajectory via global crop failure towards the feedbacks running amok,
but it looks as if your outlook doesn't include the potentially vital impact of AR on the negotiation of those two by themselves.
"A critical and largely unremarked benefit of AR is its transformative effect on negotiations,
in that it removes the wicked problem of perceived open-ended climate damages,
and also the perceived open-ended liabilities therefrom, from the discussion."

I'd entirely agree that AR should not be a stand alone first goal, and it seems implausible that it could be given the deficiency of this approach,
but neither can we afford to pursue CE + CR as a primary goal, however long that takes,
leaving AR as a later add-on and missing its lubrication of agreement, and postponing the stringently supervised R&D it requires.

Time is very very short, since the window of geopolitical coherence will likely close with the onset of global crop failures and hostilities.

Regards,

Lewis

[Tarrel]

Ha, we can't even model the climate accurately enough to predict changes, let alone trying to actively modify it! If I understand it correctly, the mainstream models didn't predict such an early reduction in arctic sea ice, for example.

It would be like sawing a bit off the leg of a table to try to level it. We'd end up sawing bits off here and there as we over did it or under did it, until there were no legs left.

And then what would we do?