On the Persistenceof Climate Change

[danieldwilliam]

In converation with Andrew Ducker I wondered aloud how long the effects of climate change would continue for after we stopped emitting carbon dioxide.

 

The best guess seems to be 1,000 years. Some modelling done by the Canadian Center for Climate Modeling and Analysis suggests that even if we stopped emitting CO2 into the atmosphere we would still be experiencing the impact a millenium from now.

 

This appears to be due to the persistence of CO2 and other greenhouse gases in the atmosphere in the atmosphere. We can expect elevated levels of greenhouse gases for hundreds of years after we stop emitting them. Along side the continued warming effect of greenhouse gases it takes a long time for the additional heat trapped on the surface of the planet to make its way into the various climate systems. The key system for the long tail of climate change seems to be the deeper levels of the southern oceans. Additional heat moves slowly into these systems until it ends up next to the Antartic ice-sheets. These in turn eventually melt leading to an increase in sea-levels of 4 meters.

 

If we stopped emitting CO2 in 2100 the model predicts some 55% of excess carbon emitted during the industrial period would still be in the atmosphere in the year 3000. The changes in climate as a result of the two effects of accumulated climate change persisting into the future and the unwinding of climate change as the distribution of CO2 changes seem to drive significant regional variation with the southern hemisphere seeing increases in tempreture after 2100 and the nothern hemisphere seeing tempretures fall back after 2100.

 

Two big worries flagged up by the model are continuing warming of Antartic seas and the consequent loss of ice from Antartica and a drying effect on northern Africa.

 

The modelling goes out for thousand years and doesn’t appear to show the effects peaking and then reversing over the model’s period.  They are still accumulating a thousand years from now.

 

As a caveat, this is one study. The climate is probably the very definition of a non-linear chaotic system and I think climate change modelling is highly dependent on all sorts of best estimates about things we don’t really understand at all well.  But it’s the best we have.

 

I have to say I’m surprised and dismayed. I’d thought that we would start to see a reversal of climate change within a hundred years or so of us reducing carbon emissions below their aborbsion rates.

 

My source for this is here

 

http://sos.noaa.gov/Docs/ngeo1047-aop.pdf

Comments

[andrewducker]

Yup. We have a huge amount of CO2 in the atmosphere that wasn't there before (well, for millions of years), and it should be put back it came from, underground. Which is, admittedly, tricky.

[fearmeforiampink]

My assumption would be that it'd take ages for it to drop out naturally, but we may be able to develop technologies that increase its drop.

[danieldwilliam.livejournal.com]

Hundreds of years for the CO2. From the commentary from the Canadian modellers what I think happens is that as soon as we stop emitting carbon dioxide a lot of CO2 is taken up by plants and ends up as bio-mass but after about a hundred years we hit an equilibrium where as much CO2 is entering the atmosphere from bio-mass decaying and the oceans venting some of the stuff they’ve stored up that we’re now basically waiting for the deep carbon cycle to kick in and turn carbon dioxide into coral reefs and snail shells and so on. So levels drop quite quickly at first and then drop much more slowly for the next five hundred years or more.

There is a neat technology I saw being touted a few years back – basically artificial trees that gathered up the CO2 so one could pump it down a disused oil well or turn it into plastic.

[fearmeforiampink]

Aye, and I remember something about dropping metal into the sea, algae forming around it, then it dropping down into the deeps, taking the algae with it.

[danieldwilliam.livejournal.com]

Which worked very well but only for a bit because the iron dropped through the sunnier upper level of the sea more quickly than the people doing it hoped for.

Which was a bit of a blow because I think the effect on the algae was better than expected.

Perhaps some form of iron coated cellulose mini-bubble might be the answer.

[fearmeforiampink]

I have a memory, though, that it *all* went down, deep down, meaning that there wasn't going to be over time some of it coming back up and returning to the cycle, so more iron needed, but it'll take it out of the system for a long time when it goes.

Yeah, I'm wondering now if you could add baloons to the iron to slow its descent…

[danieldwilliam.livejournal.com]

and through the magic of wikipedia

http://en.wikipedia.org/wiki/Iron_fertilization

Looks like it might work very well but only if you get the iron to stay topside for a while.

[rhythmaning.livejournal.com]

I'm in a good mood.

Basically, we're all fucked.

And will be for generations.

[danieldwilliam.livejournal.com]

I think there are still lots of opportunities to live a good life and to prosper.

[rosathome.livejournal.com]

The non-linear chaoticness of the climate seems to me to be the most important, most frequently ignored feature of the climate change problem. In a chaotic system, even if you reverse a cause, you have no reason to expect to reverse the consequence. You are equally likely to exacerbate the consequence. So, merely reducing CO2 emissions is virtually certain not to solve the problem. I don't know what would solve the problem, and I think any attempt to determine how we can influence the climate is doomed to the law of unintended consequences.

[danieldwilliam.livejournal.com]

Exactly.

I think of ocean currents when I think about the non-linearity, specifically the Gulf Stream which appears to have some interaction with the salt water / fresh water cycle in the far North Atlantic.

There seems to be a worry that changing the temperature and salinity of the sea in the North Atlantic will start a chain of events that dramatically slows or stops the Gulf Stream. Bad Times for Europe.

It’s not at all clear to me that reversing the overall temperature increase that lead to the changes in sea temperature and salinity reverses the interaction with the fresh water / salt water cycle and turns the Gulf Stream back on.

I think what we should expect would be a thousand years of climate change with increasing energy in the system followed by a thousand years of climate change with decreasing energy in the system but not necessarily returning to what we have now.

[f4f3.livejournal.com]

So I'm going to try and start from the proposition "Nothing is good or bad except that we make it so."

The Gulf Stream might switch off or reverse, but the Sahara might become wetter. As fresh water supplies are depleted, and water tables degrade, then the idea of more rain falling everywhere might be a life-saver (nothing desalinates on the scale of the water cycle, or more cheaply).

The thing about unintended consequences is that they can be benificial as well as detrimental, and that there are methods of reversing the CO2 levels, as well as reducing the amount produced. I do love the idea of, basically, giant, iron Aero bars being dropped in the ocean. I like the idea of CO2 being pumped into depleted oil wells.

On the one hand, I don't think we'll stop using fossil fuels until every last ounce of the stuff has been mined, drilled, blasted, sucked and fracked from the earth. On the other, as soon as that happens (and probably a few years before) then other technologies will become economically attractive, rather than just technically feasible.

Our attitude towards conservation and ecology has changed out of all recognition in less than 50 years. Our very vocabulary has been changed (when I were a lad, being "green" in some parts of Glasgow would have got you a good kicking - today it probably gets you a Duke of Edinburgh award). It seems short-sighted to think that it will remain at this early level from now on.

Generally, I think that being depressed, or angry, about this stuff isn't going to help. Helping change opinions, helping them to continue to change, is where the hope is.

[danieldwilliam.livejournal.com]

Aye – I share the general optimism, not that things will be fine without us having to take action but that we’ll be able to make a good and noble life if we chose. Every year technology makes it just that little bit easier and every year the economic growth of the Not First World makes it a bit easier for them.

I also share your view that being depressed or angry about this isn’t going to help.

On using fossil fuels until they are all used up: I’m not so sure. The current marginal price of a barrel of oil or a therm of gas or tonne of coal, puts a floor under the cost of renewables. If you can get below the floor then you win. If you can build a renewable energy system that is cheaper than the current marginal cost of fossil fuels then the hydrocarbon stays in the ground. Which is what I think we’re about to see with solar PV. It’s already cheaper than hooking up to a diesel generator in rural India.

This rather puts the onus on hydrocarbon producers to cut the cost of developing marginal deposits. Which I’m sure they will have a go at. But I think they are on a sticky wicket with that as they are trying to do something which is increasingly hard, increasingly cheaply, compared to the RE sector which is trying to do something increasingly easy, increasingly cheaply.

Or putting it another way. Hydrocarbon extraction will reach the point where each project is substantially unique whilst RE will be doing the same thing again and again.

[f4f3.livejournal.com]

That's an excellent point - I did say that the renewable options would become economically viable, but didn't think we were that close.

And on living a good and noble life - Hillhead Underground Station is being renovated just now. At the top of the escalators is a 30 foot stretch of wall which used to be blank, but now there's an Alisdair Grey quote painted across it: "Work As If You Live In The Early Days Of A Better Nation." I can't think of a better message to greet us as we set off on the working day.

[danieldwilliam.livejournal.com]

I love that quote and have done since the day I first heard it.

[danieldwilliam.livejournal.com]

Yeah, some of them are pretty close to cost parity. It’ll be solar PV first, creeping away from the equator as the cost falls and the efficiency improves. I think as soon as they start to hit parity that increases the rate at which the cost falls as the factories really gear up for mass production.


On-shore windfarms look like they will hit parity with gas power stations next decade. The rest will be a while yet. Some of the changes in infrastructure we’ll need to make to accommodate solar PV will help pave the way for them to be cheaper.

It frustrates me somewhat when climate change denier types unfavourably compare the cost of RE technologies today with the cost of hydrocarbon today. We’ve been burning coal to turn water into steam for more than 200 years. We might have learned how to do it pretty well after making the millionth steam turbine.