Quotulatiousness

May 6, 2014

Climate change and positive effects

Filed under: Economics, Environment, Media, Science — Tags: , — Nicholas @ 08:30

Matt Ridley explains that according to the experts, it’s believed that ongoing climate change actually provides net benefits for most of this century:

Climate change has done more good than harm so far and is likely to continue doing so for most of this century. This is not some barmy, right-wing fantasy; it is the consensus of expert opinion. Yet almost nobody seems to know this. Whenever I make the point in public, I am told by those who are paid to insult anybody who departs from climate alarm that I have got it embarrassingly wrong, don’t know what I am talking about, must be referring to Britain only, rather than the world as a whole, and so forth.

At first, I thought this was just their usual bluster. But then I realised that they are genuinely unaware. Good news is no news, which is why the mainstream media largely ignores all studies showing net benefits of climate change. And academics have not exactly been keen to push such analysis forward. So here follows, for possibly the first time in history, an entire article in the national press on the net benefits of climate change.

There are many likely effects of climate change: positive and negative, economic and ecological, humanitarian and financial. And if you aggregate them all, the overall effect is positive today — and likely to stay positive until around 2080. That was the conclusion of Professor Richard Tol of Sussex University after he reviewed 14 different studies [PDF] of the effects of future climate trends.

To be precise, Prof Tol calculated that climate change would be beneficial up to 2.2˚C of warming from 2009 (when he wrote his paper). This means approximately 3˚C from pre-industrial levels, since about 0.8˚C of warming has happened in the last 150 years. The latest estimates of climate sensitivity suggest that such temperatures may not be reached till the end of the century — if at all. The Intergovernmental Panel on Climate Change, whose reports define the consensis, is sticking to older assumptions, however, which would mean net benefits till about 2080. Either way, it’s a long way off.

[...]

You can choose not to believe the studies Prof Tol has collated. Or you can say the net benefit is small (which it is), you can argue that the benefits have accrued more to rich countries than poor countries (which is true) or you can emphasise that after 2080 climate change would probably do net harm to the world (which may also be true). You can even say you do not trust the models involved (though they have proved more reliable than the temperature models). But what you cannot do is deny that this is the current consensus. If you wish to accept the consensus on temperature models, then you should accept the consensus on economic benefit.

2 Comments

  1. Apologies in advance for the mini essay.

    First, let me say congratulations on posting an article which accepts completely a) that climate change is a real thing that is actually happening and b) that it’s linked to carbon emissions from human activity. This is a big step for you =P

    I appreciate that Ridley made this a non-hostile, “just the facts” look at current climate change consensus. And he was helpful enough to link to Tol’s study!

    And he’s right! Tol definitely says that “some estimates… point to initial benefits of a modest increase in temperature”

    Now, where does Tol say that 2.2 degrees is where things start to go bad? Spoiler alert: he doesn’t. What Tol says is 1.1 degrees, +- 0.7. So, 2.2 degrees is 20% higher than the best-case estimate in the paper that shows “the consensus on economic benefit”. Let me be clear: The figure 2.2 degrees Celsius appears nowhere in Tol’s paper.

    But… If the _very first_ thing Ridley quotes from Tol’s paper is wrong, then what are the odds that he isn’t actually faithfully reporting Tol’s findings? Well, let’s see what else Ridley says, and then compare it to what Tol actually wrote:

    Ridley says: “you can argue that the benefits have accrued more to rich countries than poor countries”

    Tol says: “the output of the global economy is concentrated in the temperate zone, where warming reduces heating costs and cold-related health problems. Although the world population is concentrated in the tropics, where the initial effects of climate change are probably negative, the relatively smaller size of the economy in these areas means that—at least over the interval of small increases in global temperatures—gains for the high-income areas of the world exceed losses in the low-income areas”

    So, actually the benefits _only_ accrue to rich countries. Poor countries are already suffering the losses. More people live there, and they are all being affected negatively. Good thing they don’t make as much money as us or we’d be talking about the economic drawbacks of climate change. But Ridley didn’t talk about net benefit or mention negative effects. He said poor countries were just high-fiving each other less over awesome climate change.

    Ridley says: “Either way, it’s a long way off”

    Liam interjects: Whew! Good thing it’s a long way off! Now I don’t even need to take it seriously! Why did I even bother reading Tol’s study or writing this comment? Oh, wait…

    Tol says: “The initial warming can no longer be avoided; it should be viewed as a sunk benefit”

    So… Right now we’re already locked in for the warming that causes the benefit? And letting emissions go further isn’t going to lead to increased benefits? That’s disappointing…

    Then Tol says: “Policy steps to reduce emissions of greenhouse gases in the near future would begin to have a noticeable affect on climate sometime around mid-century—which is to say, at just about the time that any medium-run economic benefits of climate change begin to decline”

    Emission reduction _now_ may be enough to preserve the economic benefits in 2080. So where does Ridley get off claiming that “It’s a long way off” like it means there’s nothing to be done today?

    Let’s be clear: Tol thinks that emission reduction needs to happen now, because the effects of emissions today are what’s going to be causing problems in 50 years. And Tol represents the current consensus, right?

    And, just for fun, let’s play “What does that word mean?”: Tol says “mid-century”. Does that mean 2080 or 2100? Or does it actually mean several decades earlier? Trick question! It means that Ridley didn’t like the estimate in the source he quoted, so he had to substitute in a different timeline from an unnamed source. Smooth.

    And, that seems to be all that Ridley wanted from the paper. Which is weird, since Tol’s entire point seems to be that action on emissions reduction needs to be taken now and Ridley never mentions that. Why don’t we just finish up looking at what Tol actually wanted to get across?

    (I’m also going to leave a lot of Tol’s analysis uncommented on. There’s a whole bunch of cool stuff in there [and some significantly more in-depth economic analysis that I have no idea how to judge], but it all leads to where I’m headed anyway)

    Tol takes a look at the known unknowns and the unknown unknowns in economic forecasts of climate change. Here are some of the more unlikely, but possible, scenarios:

    “While it is relatively easy to imagine a disaster scenario for climate change—for example, involving massive sea level rise or monsoon failure that could even lead to mass migration and violent conflict—it is not at all easy to argue that climate change will be a huge boost to economic growth.”

    Now, why is Tol mentioning any of that shit at all? That pie-in-the-sky disaster movie stuff detracts from his credibility. Luckily, he’s explaining a previous point: Statistical analysis of the uncertainty across the distributions shows far more uncertainty on the right-hand side. In this case that means it’s far more likely to have an unexpected extreme event of negative economic impact than a positive one. Again:

    “In short, the level of uncertainty here is large, and probably understated— especially in terms of failing to capture downside risks. The policy implication is that reduction of greenhouse gas emissions should err on the ambitious side.”

    And again:

    “The missing effects further emphasize that climate change may spring nasty surprises. Such risks justify greenhouse gas emission reduction beyond that recommended by a cost-benefit analysis under quantified risk.”

    Wait, didn’t Ridley say that this paper was all about the economic benefits of climate change?

    Anyway, Tol tells us that the best route to hitting these ambitious reduction targets is through a tax per ton of released carbon. He suggests $25-50/ton, but then reminds us that higher values are justified given the large uncertainty above.

    Well, I’m glad that Ridley thinks this paper is so great. He must be all for aggressive emissions reductions. I can’t think of why he didn’t bother mentioning that anywhere.

    It couldn’t possibly be because he’s grinding an axe with a source he thought no one would actually check.

    Just remember, “what you cannot do is deny that this is the current consensus”.

    So, let’s get a rousing discussion on emissions tax rates going!

    N.B. I did investigate the full post, and Ridley’s point is much longer and takes in more sources. However, there are two things to consider: 1) Nick’s quote accurately depicts what Ridley had to say about Tol’s paper and that’s what I’ve responded to. 2) Given the massive difference between what Ridley says Tol’s paper says and what Tol’s paper actually says, I’m not going to invest any more time trying to follow up anything else he claims.

    Comment by Liam — May 7, 2014 @ 11:18

  2. First, let me say congratulations on posting an article which accepts completely a) that climate change is a real thing that is actually happening and b) that it’s linked to carbon emissions from human activity. This is a big step for you =P

    Not as big a step as you think. In 2004, I said “I’ve never been all that convinced of the accuracy of the scientific evidence presented in favour of the Global Warming theory, especially as it seemed to play rather too clearly into the hands of the anti-growth, anti-capitalist, pro-world government folks. A world-wide ecological disaster, clearly caused by human action, would allow a lot of authoritarian changes which would radically reduce individual freedom and increase the degree of social control exercised by governments over the actions and movement of their citizenry.” And a bit more in the same vein in 2009.

    That is still much of my reluctance to climb on board the climate change/global warming bandwagon. If it was happening (and it appears to be, despite the multi-year pause), it still wouldn’t justify the kind of radical political and social changes many advocates were demanding. The actual, provable costs of their preferred measures far outstripped the potential costs of global warming. As Bjorn Lomborg pointed out later that year, “The cost of Kyoto compliance is at least $150 billion a year. For comparison, the UN estimates that half that amount could permanently solve the most pressing humanitarian problems in the world: it could buy clean drinking water, sanitation, basic health care and education to every single person in the world.”

    So, despite the ongoing pause, I’ve accepted that the planet is currently in a warming phase. I’m not convinced that CO2, especially man-made CO2, is the primary driver of that warming. If there’s any climatological worry I do entertain it’s actually the opposite of global warming: according to some studies, we’re overdue for an ice age, which would be a far more serious problem for humanity than any form of warming could be.

    Now, where does Tol say that 2.2 degrees is where things start to go bad? Spoiler alert: he doesn’t. What Tol says is 1.1 degrees, +- 0.7. So, 2.2 degrees is 20% higher than the best-case estimate in the paper that shows “the consensus on economic benefit”. Let me be clear: The figure 2.2 degrees Celsius appears nowhere in Tol’s paper.

    Not in the text. Look at figure 1 at the top of page 35. The point at which the median welfare impact line goes negative is at the 2.2 mark on the horizontal scale (degrees centigrade). I think that’s where Ridley got the number. In context, that seems to make sense.

    Ridley says: “you can argue that the benefits have accrued more to rich countries than poor countries”

    [...]

    So, actually the benefits _only_ accrue to rich countries.

    I think, by omitting the parenthetical clause “(which is true)” from Ridley’s article, you’re creating an impression which I certainly don’t read in the full sentence. He’s agreeing with you: the benefits did accrue to the richer countries rather than to the poor countries in the tropics.

    He said poor countries were just high-fiving each other less over awesome climate change.

    Sorry, perhaps that got edited out of the version I read.

    Tol said “Second, if pre-existing poverty is one of the main causes for vulnerability to climate change, one may wonder whether stimulating economic growth or emission abatement is the better way to reduce the effects of climate change.” That, I think is what Ridley’s emphasizing: that economic growth over the “long way off” timespan may allow poorer tropical countries to take action on the things they can currently do in richer countries.

    Comment by Nicholas — May 7, 2014 @ 13:18

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