climate change in our lifetime

Great Debates
81

If you’re asking “was there a vastly higher CO2 concentration at some point in Earth’s history?” then yes, of course I’d accept such a premise (the evidence being indirect rather than from analysing bubbles of air trapped in ice). I would, likewise, accept that the Earth was much hotter (and also much cooler) at various times in its history.

But the rate of change is what concerns me, and should concern you. Just because I don’t believe that ACC will mean the end of life on Earth, humanity or even civilisation, doesn’t mean that it can’t still spell suffering for billions of people. It’s as though I’m warning of an incoming asteroid 6 miles in diameter and you’re asking “Ok SentientMeat, how come we’re still here after the last one 65 million years ago?”

82

[QUOTE=intention]

I did not propose that “some mechanism will kick in this century”. I pointed out that as the CO2 concentration in the atmosphere has risen every year, so also the amount of CO2 sequestered by the planet has increased every year. This is an example of Le Chatelier’s Principle, and is well known to be modeled by an exponential decrease in the amount of the relevant component, in this case CO2.

This is shown by comparing the amount of CO2 emitted by the amount remaining in the atmosphere. Currently, the planet is absorbing about 3 gigatonnes of additional carbon per year (~ 6 Gtonnes are emitted annually, about 3 Gtonnes remain in the atmosphere, the rest is sequestered). Obviously, this number has risen since pre-industrial times. Get the numbers, do the math.

One of the curiosities about an exponential decay is that given a stable input, an equilibrium point is reached when the amount of the decay equals the amount of the input.

Consider a pool with a drain being filled by a large hose. At first, the hose puts in more water than flows out. But as the pool fills higher and higher, the pressure on the outlet increases and the water flows out faster and faster. At some point, they are equal, and the pool will not fill any more.

In other words, as I said before, if emissions stabilize, atmospheric concentrations will not continue to rise indefinitely.

Glad to hear about the lake in Fiji, however, and now all of your ignorance is vanquished.

w.
[/QUOTE]
Of all your claims, intention, this is surely the most faith-based - a charge you are quick to level at others here. You admit that 3 gigatonnes of CO2 per year are not being absorbed, but pull from your hat the assumption that this number will start to decrease (presumably soon, ie. in the next decade or so?). Believe me, I wish for this miracle as strongly as you, but am so overwhelmed by skepticism (see, I’ve got plenty of it too!) that it merely seems so much wishful thinking.

What is the actual mechanism of this vastly increased CO2 uptake? More plants, more plankton, more reflection of sunlight? Again, that would be wonderful. But it’s just not happening. Rainforests are being felled, phytoplankton is becoming less productive, white regions are melting to leave dark, methane-releasing regions.

If your miracle doesn’t arrive within the next few decades, it might as well not bother turning up at all, so high will the concentrations be by then. And surely, given your hose analogy, the water can’t start filling up the barrel quicker, as though the increased pressure reduces the speed of the outflow.

So, would you be willing to make a bet? If the amount of CO2 sequestered shows an average increase over the next five years, in line with your predicted miracle, I will lose the bet. If it stays the same, I win. (If it decreases, I win big!)

Are you willing to stake your honour (or something else if you like) on the next five years’ data?

83

[QUOTE=intention]
Oh, please. Future concentrations of CO2 are not facts. They are projections, or scenarios, or forecasts, but they are not facts. Please learn to distinguish facts from other types of information, your life will be much less stressful.

Nor is 600 ppmv even a reasonable forecast. All of the B scenarios of the IPCC are below that level, and even those are based on highly questionable economic scenarios. In addition, they all assume larger emission rates than the present, while you have specified our current rate of emission above.

Would a CO2 level of 0.6% have only “insignificant” consequences? The truth is, we don’t know. Here’s one way to look at it.

Without the greenhouse effect, the temperature of the earth would be about 19° lower. The total greenhouse downwelling radiation is about 325 watts/m2. This means that each watt/m2 has warmed the earth by about a tenth of a degree. Let’s double that to be on the safe side.

Current CO2 level is about 380 ppmv, increase is 3.7 w/m2 time log2(600/380) = 2.5 w/m2 = half a degree.

We had half a degree warming in the 20th century without significant effects.

w.
[/QUOTE]
Well, the 600ppm figure assumes an increase per year of 2-3ppm, the current level of increase, for another century. So the only way it can be “unreasonable” is if your miracle mechanism arrives, and I would hope that you could at least entertain the possibility that it might not. (IIRC, the B scenarios also assume that we don’t do absolutely nothing, emission-wise - a course of action you appear to advocate. I may be wrong here.)

As for the “half a degree”, don’t you realise that you are hoisting yourself by your own petard? You are at great pains to emphasise that we just don’t know how global climate works, and then adopt the absolute most optimistic estimate for its sensitivity to increased CO2! This, to me, is as unreasonable as adopting the most pessimistic estimates of 10 degrees or so - the figures we, both of us, roll our eyes when sensationalist news agencies use in their headlines.

Also, don’t you think there might be a time lag, such that we haven’t yet seen all the warming effects of the 20th century’s emissions? As you say, repeatedly, we just don’t know - we could merely be seeing the warming effects of the CO2 concentrations in the 1950’s or something. Measuring the temperature at midnight on 1/1/2000 and saying “See, half a degree!” smacks of legerdemain even to a layperson like me.

84

Again I ask: Why, then, are you only assuming positive feedbacks in your prediction of a future concentration stabilisation?

Agreed. Let us, in addition, look at ways in which future problems might, just might be ameliorated. In Kimstus’s analogy, let us at least stop drinking faster.

85

Erratum: Why, then, are you only assuming negative feedbacks in your prediction of a future concentration stabilisation?

86

I really can’t be bothered with this.

Actually I think that the collective IQ of humanity was never that high, but it is sinking dismally.

If Jonathon Swift were around these days, he would have rich material.

If I were smarter I would be rich and famous … for running round yelling that I had read the future in the entrails of a computer.

87

[QUOTE=MrDibble]
Geologist checking in:
Yes, isostasy leads to rising and falling. As you noted the rates can be as high as several cm a century. But also as you noted, this is not a uniform effect. In some places there’s rise, in others, depression under sediment load. Consider that global sea level rise would be just that - thermal expansion and increased melt would lead to a rise of some sort everywhere, and at a far greater rate than isostatic rebound. There are terraines still rising from the last Ice Age, but we’re feeling the first rising effects of ACC right now. Those are way different timescales, and it’d be incredibly naive to think that isostatic rebound woul cancel out sea level rise.

Also, a coupling of ACC-fed drought and topsoil dessication with ACC-fed superstorms or increased storm frequency would lead to increased erosion on continents, meaning while the continental interiors undergo more isostatic uplift because they no longer have to bear the mass of all that nasty topsoil, the coastal regions and shelf will have an increased sediment load, leading to increased isostatic depression. This could be seen as another (albeit slow) mechanism exacerbating sea level rise .
[/QUOTE]

Question: how much of the sinking of New Orleans (subsiding at about 12’/century) is due to the mass of the Mississippi Delta crushing and compacting itself? Mankind may not be the ONLY guilty party, in the sinking of the land in this region.

88

[QUOTE=intention]

Sensitivity (°C per watt/m2 forcing) = 33°C/325 w/m2= 0.1°C per watt/m2.

[/QUOTE]

This estimate of the climate sensitivity is roughly 7X lower than the mean estimates in the field and I imagine it would be quite difficult to explain the ice age - interglacial temperature changes with this sort of estimate!

89

intention, I think that congratulations are in order. You may well have set the record for the highest amount of junk science, misinformation, and distractions ever crammed into a single post at the Straight Dope Message Board. Write this one down, because it’s one for the record books.

[QUOTE=intention]
Take Tuvalu as an example. The whole furor over Tuvalu was started by a long article in the Sierra Club magazine about how Tuvalu was hit so hard by rising seas that a missionary’s cabin, that had stood for over 100 years, had been eaten away by rising sea levels.
[/quote]

So you claim that the only reason anyone cares about the possibility of sea level rise near Tuvalu is because of an article about a missionary’s cabin.

Now when I read the Governor General of tuvalu’s statement to the UN about the threat that climate change poses to his country, I don’t see anything about a Sierra Club article about a missionary’s cabin. In fact, I don’t see anything about the Sierra Club or missionaries or cabins. Are you claiming that the Governor General knows less about what’s happening in his own country than you do? That he makes his judgements based articles from foreign environmental groups rather than on the facts about what’s happening in his own country.

Consider this: Tuvalu joined the UN in 2000. It did so entirely to get a chance to express concerns about global warming. The cost of participating in the UN and in other activism related to global warming consumes a considerable chunk of the country’s 12 million dollar economy. Are you trying to tell me that the country throws away all of this money only because they were fooled by an article in Sieraa Club magazine? No country would be that stupid. Even if the government tried to do so, the people would not permit it.

Tuvalu would not devote this effort to informing the world of its vulnerability to climate change if climate change was not already happening.

That article says nothing about global warming, positive or negative. Furthermore, it discusses only the effects on one small island, not the whole nation. furthermore, it is 11 years out of date.

Let’s try here

That, you see, is a current article that quote real scientists from Tuvalu, states that flooding has increased throughout the nation, and ties that flooding to global warming and rising sea levels. You will also note that it says nothing about missionaries or cabins.

Oh really? When, pray tell, did I mention anything about a missionary’s cabin? I don’t think that I ever did. I had already provided one article about evacuations from Tuvalu, one that never mentioned missionaries or cabins either. No one mentioned them except you. It’s clear that you really love talking about this missionary’s cabin, but you’re only blathering to yourself because it has nothing to do with the debate at hand.

There are three problems with this sentence.

  1. First, you somehow failed to mention that both Australia and New Zealand have increased immigration quotas for Tuvalu because of climate change. So you’re asking us to believe that a tiny, destitute nation has somehow successfully conned two of the richest and most advanced nations in the world.

  2. The decisions from these two nations had nothing to do with missionary cabins, or at least the one for New Zealand doesn’t. If you want to read it, it’s linked from the wikipedia article on Tuvalu. These decisions were based on the most up-to-date climate science.

  3. The immigration offices in those two countries are famously hard-assed bureaucracies. To imply that they could be “conned” into allowing more immigration without solid data is absurd. It would be easier to con the Catholic Church into supporting abortion.

Let’s go back to the summary of what the Governor General said.

So on the one hand we have actual officials from Tuvalu, and on the other an anonymous internet user. Guess who I’m going to believe.

Why exactly am I remembering this cabin that no one but you cares about?

You suppose incorrectly. And as the second half of your post deals with this island that no one other than yourself ever mentioned, I see no reason to care about it. It’s telling that you’d rather respond to your own claims about global warming than anyone else’s.

90

Isn’t it the height of arrogance to think we can destroy the earth?

91

Well, I don’t think that anyone is claiming that we will destroy the earth. However, we do seem to have the power to change its atmospheric chemical composition and climate considerably…and, in particular, to make it less hospitable for ourselves and many other species.

92

[QUOTE=Don26]
Isn’t it the height of arrogance to think we can destroy the earth?
[/QUOTE]

It is not really about destroying Earth. It is more about destroying Earth’s ability to hold all of us at the standards of comfort we are accustomed to. That we can do with the push of a button.

93

Can anyone make it rain? Snow? Hail? Not be cloudy? Make the wind blow?
Uh, No. no. no. no. no. Why, we don’t have that kind of power. Not intentionally nor unintentionally

94

Don26: Your argument sounds more theological than scientific at the moment.

95

I never claimed it was scientific, but, neither is it theological, and btw, why is that a slur?
The idea that we have that much power over this planet just strikes me as preposterous.

96

To those confronting reality, it doesn’t do much good to hear someone claiming that the reality is preposterous.

[QUOTE=intention]
I did read the article on the Maldives. While they made the claim that it was also from sea level rise, they presented no evidence to back it up. They did provide evidence, on the other hand, that the reefs have been destroyed. Regarding sea level rise, if you have any evidence that the sea level rise in the Maldives has shown any sign of change from its historical rate, bring it on … if not, you might reconsider your claim.

Remember also that a coral atoll exists in a balance between wind (tearing it down) and reef growth (building it up). It is a delicate balance, and easily disturbed. Cutting down trees (an ugly habit of humanoids) for example can kill an atoll just as surely as destroying the coral. Finally, the Maldives were hard hit by the New Years tsunami. It’s easy to say “it’s from sea level rise”. I do not consider that a random person making that claim establishes anything.

[/QUOTE]

It was you who linked to the article by Goreau, Hilbertz, and Hakeem. If you think they’re untrustworthy, that their statements are worthless, that their article is no better than “some random person making that claim”, then why did you first cite them as authoritative? If they can lie about climate change and sea levels, then they can also lie about coral reefs. How can you accept one set of statements and not the other? Is it that when they started writing the article they were part of the big, bad, politically correct global warming hoax, and then they changed their minds later on? Is it that Goreau and Hakeem are honest scientists writing about the coral reefs, but nasty little Hilbertz snuck in the material about climate change? Or is it that you’ve realized that the only way to justify the policy of inaction on climate change is to cherry-pick the data, accepting anything that argues against damage from global warming while rejecting anything that argues for it, even when it’s from the same source?

97

[QUOTE=Don26]
Can anyone make it rain? Snow? Hail? Not be cloudy? Make the wind blow?
Uh, No. no. no. no. no. Why, we don’t have that kind of power. Not intentionally nor unintentionally
[/QUOTE]

We can make it rain. The technique is called cloud-seeding , and it’s a straightforward process of dropping particles of CO2 into certain clouds. Water molecules coalesce around the particles and soon become heavy enough to fall as raindrops.

Ignorance fought.

98

[QUOTE=ITR champion]
We can make it rain. The technique is called cloud-seeding , and it’s a straightforward process of dropping particles of CO2 into certain clouds. Water molecules coalesce around the particles and soon become heavy enough to fall as raindrops.

Ignorance fought.
[/QUOTE]

Ignorance demonstrated perhaps…
Can ya make a cloud, Skippy?

99

We’ve made plenty of acid rain.

100

[QUOTE=Don26]
Ignorance demonstrated perhaps…
[/quote]

If that’s your goal, then mission accomplished.

Personally, no. But that’s not what’s at issue in the global warming debate.