Emission scenarios and economic impacts of climate change

[-1=e^ipi]

the study being completely focused on temperature only

You can easily repeat the methodology to estimate impacts of precipitation and other things. The authors chose not to, maybe because they wanted to focus on temperature or maybe because they had limited journal space.

perhaps that's why the U.S. and China are finally on the mitigation bandwagon, hey!

You are deluded if you think China is on the mitigation bandwagon. China is just pledging to do BAU while trying to appear as if they are performing mitigations. It's all posturing to obtain political leverage over the US and EU.

so are you a slowdown alarmist?

Either the slowdown exists or it doesn't. It's not hard to figure out. Both BEST and Cowtan & Way show a slowdown.

You know there's significant analysis countering the suggestion a slowdown even occurred

Yeah and it's a joke. It shows how invested some people are in the alarmist narrative. Acknowledging the existence of the slowdown doesn't somehow mean that mitigation policy isn't justified.

fake-skeptics downplay/ignore what the warming rate might have been had there not been that anomalous 'perfect storm' line-up of natural factors.

And a decade + ago, alarmists were downplaying natural variability and claiming that basically all the warming from like 1970 to 2000 was anthropogenic.

Point is that natural variability matters, and the implication is that climate sensitivity is likely lower than what the alarmists were claiming a decade + ago. Yet the alarmists are still clinging to the upper half of the IPCC's ECS range even as empirical evidence suggests otherwise.

[-1=e^ipi]

That's why you mentioned him again just a few posts back!

Because he commented on the paper and I respect him as an economist. He probably has some decent criticisms of the Burke et al 2015 result.

Intuitively productivity is a function of technology - not temperature.

It's a function of both, as well as rainfall and other things. I think an empirical fit, where the logarithm of productivity is a roughly quadratic function of temperature, a quadratic function of precipitation, and a linear function of time might be reasonable (or maybe you need more interaction terms). In any case, it seems like productivity losses due to temperature changes are the strongest justification for mitigation policy.

I look forward to you publishing your Euler-speak!

What I wrote follows from performing a parabolic fit that is fixed 0 warming and is fixed at 2.5 C - 3 C of warming. If the estimates around 1 C were overestimates, then this suggests that the linear term is smaller in magnitude while the quadratic term is larger in magnitude. That's a very simple concept and is far too trivial for any publisher to have any incentive to public.

[TimG]

It's a function of both, as well as rainfall and other things.

All of which interplay. I don't believe one can separate out one of those factors and develop an empirical model that tells you the relationship between a single factor and productivity. More importantly, technology allows adaptations which mitigate the effects of any such relationship. The only thing that makes sense is eventually there will be a drop off as the environment becomes simply too hot for humans but that is way beyond the range of likely climate changes. Edited October 24, 2015 by TimG

[-1=e^ipi]

All of which interplay. I don't believe one can separate out one of those factors and develop an empirical model that tells you the relationship between a single factor and productivity.

You can if you construct the model to be overly simplistic. The Burke et al 2015 paper does this for temperature. Of course you probably want to to depend on multiple factors, but that isn't very difficult since the methodology is a simple regression.

More importantly, technology allows adaptations which mitigate the effects of any such relationship.

And you can estimate this effect by including time in the regression.

[waldo]

Also, there is a bit of irony here.

is it... the fact you said diddly squat about the study's temperature-to-productivity correlation that includes agricultural activity in both rich and poor countries? Sort of "puts the boots to" those peddling that "CO2 fertilization effect"... notwithstanding the "CO2 is simply plant food meme". Which of those was yours again... which of those had you laying down a brazillion posts all attempting to leverage nothing more than non-real world, controlled, isolated greenhouse/hood enclosure studies?

[-1=e^ipi]

Sort of "puts the boots to" those peddling that "CO2 fertilization effect"

A study that doesn't take into account the CO2 fertilization effect 'puts boots to' the CO2 fertilization effect... That doesn't make sense.

"CO2 is simply plant food meme". Which of those was yours again

I have never said anything along those lines. You wish I did though, which is why you keep strawmaning me.

[waldo]

A study that doesn't take into account the CO2 fertilization effect 'puts boots to' the CO2 fertilization effect... That doesn't make sense.

the study's temperature-to-productivity correlation that includes agricultural activity in both rich and poor countries...

[-1=e^ipi]

the study's temperature-to-productivity correlation that includes agricultural activity in both rich and poor countries...

And temperature is not atmospheric CO2. Just like how temperature is not precipitation and you were complaining a few posts ago that the study doesn't take into account changes in precipitation patterns.

[waldo]

And temperature is not atmospheric CO2. Just like how temperature is not precipitation and you were complaining a few posts ago that the study doesn't take into account changes in precipitation patterns.

temperature-CO2 correlation. Notwithstanding, as you're well aware, I separately punted your "CO2 global crop yield increase" nonsense that you presumed to attribute to the "CO2 fertilization effect"... that you substantiated by your, again, reliance upon non-real world, controlled and isolated greenhouse enclosure studies.

.

[-1=e^ipi]

temperature-CO2 correlation.

The correlation isn't that great over the time period and really I think they should have stuck with cross-section data.

Also, given that CO2 concentrations aren't measured in Celcius, you can't infer anything about the CO2 fertilization effect from the results of temperature on productivity, other than the fact that they didn't control for CO2 level, which suggests a slight underestimation in the productivity effects (although an overestimation for other reasons).

[waldo]

The correlation isn't that great over the time period and really I think they should have stuck with cross-section data.

over that 1960-2010 study period: esrl-CO2 (Mauna Loa) versus hadcrut4 surface temperature record (per WoodForTrees interactive plot):

[-1=e^ipi]

Like I said, the correlation isn't that great. Also, over this time period, AMO and CO2 are highly correlated, but that correlation breaks down outside this period, which means pretending that the CO2 and AMO relationship will hold till 2100 will greatly bias results.

Let alone the fact that the study deals with local temperatures. So 400 ppm would corresponds to a different temperature in say Ottawa compared to Miami. Which means that you can't infer anything about the CO2 fertilization effect from the Berke et al. 2015 study.

[-1=e^ipi]

Hey Waldo, I have an idea. Email Burke et al. about your discovery. I'm sure that they would be super pleased that their study somehow accounts for the CO2 fertilization effect.

[-1=e^ipi]

Okay, Marshall Burke's email is [email protected].

Come on Waldo, email him about your discovery. If people are more aware of your discovery it could influence the Paris negotiations. Think of all the good you could cause! You should totally email Burke for the greater good!

Edited October 26, 2015 by -1=e^ipi

[-1=e^ipi]

Here's an interesting paper that estimates the effect of CO2 on Net Primary Production:

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.2003.00021.x/pdf

Basically, Global Net Primary Production is approximately proportional to (1 + 0.34*ln(CO2/278)), where CO2 is atmospheric CO2 in ppm. So a doubling of atmospheric CO2 increases global net primary production by 24%.

[waldo]

Let alone the fact that the study deals with local temperatures... Which means that you can't infer anything about the CO2 fertilization effect from the Berke et al. 2015 study.

it's you claiming increased global crop yields... and you're relying upon the most localized of non-substantiation you can in your lame attempts to leverage non-real world, isolated and controlled greenhouse hood/enclosure studies - how hypocritical of you! Notwithstanding, of course, the study is using those local/regional temperatures to arrive at a global average temperature of 13°C (55°F) as being the most economically optimal

in the context of reduced productivity... are you segmenting out your hobby-horse "global crop yields" from that reduction? Alternatively, how do you explain/rationalize reduced productivity with your claimed/unsubstantiated claims of increased global crop yields?

the rest of your nonsense, as I replied to in your earlier taunting status update... is simply you being the strawmanKing!

[waldo]

Here's an interesting paper that estimates the effect of CO2 on Net Primary Production:

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.2003.00021.x/pdf

Basically, Global Net Primary Production is approximately proportional to (1 + 0.34*ln(CO2/278)), where CO2 is atmospheric CO2 in ppm. So a doubling of atmospheric CO2 increases global net primary production by 24%.

do you find that somewhat dated paper "interesting" since it aligns with your non-real world substantiation? From your own linked study:

...shows that current hypotheses about CO2 fertilization effect (and thus projections of the related carbon sink) are very sensitive to the choice of driving forces taken into account. Consideration of the light limitation inside a canopy dramatically changes the pattern of climate dependence as derived on the assumption that this factor is not important. What will happen when proper attention will be paid to another factor such as nitrogen limitation, for example? The meta-analysis of CO2 fertilization effects in case of European forest species (Medlyn et al., 1999) suggests that nitrogen limitation may really take place there: across the 15 field experiments the rate of light-saturated photosynthesis was increased only by 51% at doubled CO2. Therefore, we may suppose that taking into account nitrogen limitation will significantly reduce our estimates of the growth factor for tundra and boreal forest.

and that's just with regard to a single nutrient factor... without considerations of other/all nutrient limitations, water availability, warming itself (e.g., decomposition and CO2 return), fires, pests, high temperatures, permafrost thawing, etc., etc., etc.! As I've provided in the past, you simply choose to ignore the latest IPCC AR5 report content, the latest USGCRP report content... that counters your ongoing unsubstantiated claims of "increased global crop yields". Of course you do!

[-1=e^ipi]

Alternatively, how do you explain/rationalize reduced productivity with your claimed/unsubstantiated claims of increased global crop yields?

I already explained this, but you refuse to acknowledge the difference between full and partial derivatives.

[-1=e^ipi]

After someone pointed me to an article by the CATO institute (http://www.cato.org/publications/testimony/analysis-obama-administrations-social-cost-carbon) which claimed that the CO2 fertilization effect used by Anthoff and Tol in their FUND model (page 10 has CO2 fertilization parameters) was overestimated by a factor of 2-3 based on results by Idso 2013 (http://web.uvic.ca/~kooten/Agriculture/CO2FoodBenefit%282013%29.pdf), I tried to see where the discrepancy arises.

It seems that FACE studies are showing roughly 50% of the CO2 fertilization effect compared to enclosure studies (https://www.sciencemag.org/content/312/5782/1918.abstract), for whatever reason. Furthermore, Idso assumes a linear relationship between yields and CO2 concentrations, as opposed to a logarithmic approximation, which means that Idso is overestimating the CO2 fertilization effect for an increase in atmospheric CO2 by 300 ppm given the data used.

So CATO and Idso seem to be full of nonsense, the FUND model parameters seem reasonable (though I don't get why they use a truncated normal distribution as opposed to a lognormal distribution), and the other integrated assessment models used by the EPA (DICE and PAGE) don't directly account for the CO2 fertilization effect (PAGE doesn't have it and DICE's quadratic damage function somewhat accounts for it but is likely inadequate).

[-1=e^ipi]

Our understanding of the impacts of ocean acidification on Coral growth may be completely wrong:

https://www.newscientist.com/article/dn28468-growing-corals-bathe-themselves-in-acid-without-suffering-damage/

[-1=e^ipi]

Okay, I've tracked down this 2.7 C warming number that keeps getting referred to with respect to Paris. Apparently it comes from an International Energy Agency report (https://www.iea.org/media/news/WEO_INDC_Paper_Final_WEB.PDF) which used a model known as MAGICC to predict temperature changes by 2100. Of course this IEA failed to mention the equilibrium climate sensitivity used. From what I can tell from the MAGICC site (http://www.cgd.ucar.edu/cas/wigley/magicc/), the default ECS is 3.0 C, which suggests that this 2.7 C number that keeps getting thrown around is all based in an ECS of 2.7 C.

Also, the IEA report does indicate what the 2.7 C is compared to. Is it 2.7 C rise relative to today's temperature or relative to pre-industrial temperature? I think it's relative to pre-industrial based on what I have read from Bjorn Lomborg, but you would think that the basis of this 2.7 C value that keeps getting thrown around would be easier to track down.

[-1=e^ipi]

Posted this a few days ago... but no one seems interested. http://www.mapleleafweb.com/forums/topic/25325-expected-social-welfare-maximization/

[-1=e^ipi]

New paper out by Richard Tol. https://www.sussex.ac.uk/webteam/gateway/file.php?name=wps-75-2015.pdf&site=24

The results of climate economists Tol, Nordhaus and Weitzman all seem to suggest that climate change reduces global GDP by approximately 0.2%*(deltaT)^2, where deltaT is the temperature minus pre-industrial temperatures in celcius.

[-1=e^ipi]

Here is a recent critique of RCP 8.5.

http://judithcurry.com/2015/12/13/a-closer-look-at-scenario-rcp8-5/

[-1=e^ipi]

The temperature response to CO2 emissions used in integrated assessment models is generally unrealistic and inconsistent with general circulation models.

This suggests that current optimal level of taxation is closer to $15/ton CO2 than $20/ton CO2, and the difference on global well being due to an inappropriately applied tax is $1 trillion in net present value of utility.

https://judithcurry.com/2016/08/15/abnormal-climate-response-of-the-dice-iam-a-trillion-dollar-error/

Looks like an emissions path that peaks at 600 ppm CO2 and 3C above preindustrial levels is optimal.

Edited August 26, 2016 by -1=e^ipi