#199–“Names appearing on this blog’s roll-call put in the shade any peer review. . .”
Hardly the point. It isn’t who does the looking, it’s the skill, talent and commitment with which the looking is done. In peer review, there is an implicit commitment to take the ideas seriously, and to examine (quite often in a mode rather like destructive testing) how ‘robust’ they are.
It sounds to me as if what you are saying is that you have a hobby, and you like it the way it is. Nothing wrong with that. But it’s not likely to shake the world (or any subset thereof.)
Just saying.
JCHsays
Dan H. – what does it mean when you say a greenhouse has CO2 at 1000 ppm? In my experience it means CO2 will not, hopefully, drop to a limiting level ppm and suspend uptake. This is something that never happens, that I know of, in a cornfield – not in 1812, not in 1912, and not in 2012.
Ray Ladburysays
Dan H.,
I’m gonna go out on a limb and guess that you aren’t a gardener. If you were, you would realize that the important thing is NOT whether CO2 promotes growth of plants, but whether it promotes growth of the plants we need to support a population of 9-10 billion by 2050.
All indications are that rising temperatures reduce grain yields–especially of rice and winter wheat.
Do not confuse fetid with fertile.
Ray Ladburysays
Vukcevic,
A blog post and comments cannot substitute for a detailed review by experts. As scientists, reviewing work within our expertise is part of our day job (albeit, usually an unpaid part). You simply will not get the sort of detail in a blog comment that you do in a peer review.
Then, too, there is the problem of sorting the wheat from the chaff. How do you know the commenter could actually find his ass with both hands and a GPS on the subject matter? The intertubes are full of bullshitters and wannabes. An expert sees through them pretty easily, but they can do a convincing immitation if you are not expert inthe subject matter.
This is not to say that peer review is perfect. The reviewers have the imprimatur of the editors, but both sometimes make mistakes. That is why the ultimate stamp of approval comes when your colleagues–even if they are brand new colleagues–realize the usefulness of the ideas, data or methods you introduce. This is my definition of scientific consensus. Scince–it works, and there is a reason why it works the way it does.
# 199 vukcevic …Names appearing on this blog’s roll-call put in the shade any peer review,…..
roll-call is on this page ….an inquisitive reader or poster of this blog.
is occasionally but not too often found here
Ray,
Yes, I am a gardener, but only small time. My father grew up in Iowa, and I experienced many a farm there. Whether we can grow enought food to support the population of 2050 is a whole different question. Paul Ehrlich feared that mass starvation would occur starting in the 1970s due to overpopulation. Agricultural advances since then have increased food production to ease these fears. Feeding the future population may require further advances. Knowing how plants grow in an atmosphere with higher CO2 concentrations will certainly aid these developments. For examplee, see these experiments on wheat.
[Response: Maybe it’s just me, but if I had an agenda I was trying to push when citing a scientific paper, I think I would at least read say, the abstract, so that I knew how representative it was, or at least what it’s major focus was, or failing those, that it at least didn’t contradict my position. Crazy eh?–Jim]
Lynn Vincentnathansays
Here’s a new one denialists are using, with a horizontal sine wave of temps on into the future; what is the scientific response to this:
Abstract:
We compare the performance of a recently proposed empirical climate model based on astronomical harmonics against all CMIP3 available general circulation climate models (GCM) used by the IPCC (2007) to interpret the 20th century global surface temperature. The proposed astronomical empirical climate model assumes that the climate is resonating with, or synchronized to a set of natural harmonics that, in previous works (Scafetta, 2010b, 2011b), have been associated to the solar system planetary motion, which is mostly determined by Jupiter and Saturn. We show that the GCMs fail to reproduce the major decadal and multidecadal oscillations found in the global surface temperature record from 1850 to 2011. On the contrary, the proposed harmonic model (which herein uses cycles with 9.1, 10–10.5, 20–21, 60–62 year periods) is found to well reconstruct the observed climate oscillations from 1850 to 2011, and it is shown to be able to forecast the climate oscillations from 1950 to 2011 using the data covering the period 1850–1950, and vice versa. The 9.1-year cycle is shown to be likely related to a decadal Soli/Lunar tidal oscillation, while the 10–10.5, 20–21 and 60–62 year cycles are synchronous to solar and heliospheric planetary oscillations. We show that the IPCC GCM’s claim that all warming observed from 1970 to 2000 has been anthropogenically induced is erroneous because of the GCM failure in reconstructing the quasi 20-year and 60-year climatic cycles. Finally, we show how the presence of these large natural cycles can be used to correct the IPCC projected anthropogenic warming trend for the 21st century. By combining this corrected trend with the natural cycles, we show that the temperature may not significantly increase during the next 30 years mostly because of the negative phase of the 60-year cycle. If multisecular natural cycles (which according to some authors have significantly contributed to the observed 1700–2010 warming and may contribute to an additional natural cooling by 2100) are ignored, the same IPCC projected anthropogenic emissions would imply a global warming by about 0.3–1.2 °C by 2100, contrary to the IPCC 1.0–3.6 °C projected warming. The results of this paper reinforce previous claims that the relevant physical mechanisms that explain the detected climatic cycles are still missing in the current GCMs and that climate variations at the multidecadal scales are astronomically induced and, in first approximation, can be forecast.
[Response: This is just another curve fit with no predictability. The analysis of the GCMs assumes (completely incorrectly) that all climate variability in them is forced and is misconceived from the get-go. Even volcanic impacts are ignored in favor of celestial forcings that are more akin to astrology than science. An embarrassment to the author and the journal. – gavin]
JCHsays
Dan H – greenhouses worked very well before enhanced CO2 fertilization. The sequence was not: we just invented this CO2 enhancement equipment, what we need now is some sort of glass enclosure.
The site says that when windows are open, 390 ppm, the enhancement should be done for just two hours. Does this strike you as odd? When it’s 400 ppm outside, will the two hours drop to one and a half hours?
Ron R.says
Doing an unscientific review of some of the many papers re: CO2 and N (some of which appear conflicting). Here’s a list authors I found.
Only one name, Benjamin Z. Houlton, appeared twice. One wonders if these people talk to each other.
Anyway, I wonder if it might be possible for RC to invite the lead authors of the FACE study to do a guest editorial. What they found and what still remains unknown. Might clear up some confusion.
siddsays
Re:Boyce paper in Nature claiming phytoplankton decrease
Please note the brief communications commenting on this paper. The finding does not appear to be robust.
Ray Ladburysays
Paul Ehrlich failed to anticipate that humans would learn to survive by eating petroleum–with the intermediate step of turning it into corn and soy, and in the process hastening the depletion of not just this one-time windfall, but also aquifers, water quality and soil fertility.
As I have said before, there are two types of demographers–Malthusians and those who are bad at math.
I still can’t believe that no one has done a correlation study of earthquakes on Pluto to climate change on Earth.
Just imagine, the magical wonders of curve fitting producing fanciful results to titillate the minds of those that don’t want to know…
Lynn Vincentnathansays
RE #208, thanks for your response, Gavin — it was duly transmitted to the said skeptics.
I pointed out before your response that if this were so — planetary harmonic impacts on climate — then that would not overturn the laws of physics on which the GH effect was based, so it would be similar to the solar irradiation cycles — in the troughs, we might expect some cooling or only slight warming, considering the impact of AGW, and in the peaks we would expect the AGW to piggy back on the other warming and really put us in deep do-do.
To compliment #203 Ray Ladbury, crop yield production is already significant in the numbers in relation to thermal limits, and in context of increased RF/temp. Changes in atmospheric hydrology will increasingly to impact crop productivity as well as soil moisture drop and temperature will increase acres burned and result in increasing crop loss.
[When I tried clicking it it started in the middle ??? so if that happens just click in the timeline at the beginning. Chris Field does an excellent overview on these issues.]
NPP data indicates that it really doesn’t matter that much though. What good does it do to have larger plants form increased CO2 if the plants burn up so you never even have a chance to eat them?
M Hofmann et al 2011 Environ. Res. Lett. 6 034035
doi:10.1088/1748-9326/6/3/034035
Declining ocean chlorophyll under unabated anthropogenic CO2 emissions
“… numerical simulations reveal only weak reductions in chlorophyll(a) concentrations during the twentieth century, but project a 50% decline between 2000 and 2200. We identify a local and a remotely acting mechanism for this reduction in the North Atlantic …”
flxiblesays
For Ray and Hank, more appropriate here than on the methane model thread, the always interesting CBC program Quirks and Quarks today had a piece with Dr Drew Shindell about human caused methane releases and black carbon/soot effects on climate [scroll to the bottom, should be able to listen]. The discussion concerned this study, a partial solution for society to try to limit the damage.
The study is related to this 2010 finding: Phytoplankton Population Drops 40 Percent Since 1950
Researchers find trouble among phytoplankton, the base of the food chain, which has implications for the marine food web and the world’s carbon cycle http://www.scientificamerican.com/article.cfm?id=phytoplankton-population
And it appears that the new study is a bit too conservative? For instance no methane forcing and current emission scenario incorporated. So i don’t see why ocean chlorophyll and following phytoplankton decline should not go even lower.
“We explore these questions using an ocean general circulation model forced with documented historic and projected future anthropogenic emissions of carbon dioxide according to the IPCC SRES A1FI emission scenario until the year 2100. We further extend the time period covered by the A1FI scenario by assuming a linear decline in emissions from 2100 to 2200 and keeping them at zero levels until 2400.”
I have just completed building a $15,000+ greenhouse.
One of the most important things about a greenhouse is how to accomplish air exchange without affecting the temperature or humidity too much (I used my own design, based on lots of input from knowledgeable friends, and the requirements of the species of plants I intend to grow). As plants metabolize CO2, they release oxygen. If this oxygen is not carried away and replaced by more CO2 at a sufficient rate (which varies substantially depending on species), the plants will suffer. Air circulation and exchange is vital. For this reason, greenhouses DO NOT have high levels of CO2, unless someone is intentionally injecting CO2 into them. They have at most the level of CO2 of the air that is being exchanged. How could they possibly have more? What would be generating the CO2?
[Response:He’s talking about artificial enhancement to ~ doubled levels that some production greenhouses use to speed growth.–Jim]
No one is dismissing anything except your faulty logic.
Ken Lambertsays
Top five climate science points for 2011:
1. Dr Hansen says warming imbalance for the last 5-6 years is about +0.6W/m2.
2. Dr Trenberth says that it is still about +0.9W/m2 confirmed by models.
3. Dr Hansen says that the reduction is due to Chinese aerosols.
4. Dr Trenberth says that he does not believe that for a minute and the missing heat is still to be found in the oceans.
5. Professor CERES is still reading the imbalance at +6.4W/m2.
Craig Nazorsays
Well, I have been to A LOT of greenhouses, and the “typical greenhouse,” as Dan called it, does not inject CO2. CO2 injection will only work well in colder climates, as air exchange must be discontinued for CO2 injection to be beneficial. If there is no air exchange, then the cost of cooling the greenhouse increases substantially. Greenhouses are not closed systems.
Here in Texas, a closed greenhouse during the day is extremely expensive to keep cool during much of the year. And since AGW is making temperatures warmer, that problem is getting worse, not better.
[Response:Right, not an option in any warm climate, even with whitewash applied.]
My point is that while CO2 has an effect on plants, and while that effect is worth understanding, there is no credible evidence that increased atmospheric CO2 will be beneficial for human societies on the whole, and there is plenty of credible evidence that just the opposite is most likely.
Dan H.says
Craig,
In your specific case, the practice may not be efficient. Here, in the “colder climates” it works quite well, as you maintain. No one ever implied that the greenhouse was a “closed system.”
The whole previous discussion was about the CO2 effect upon plants. The effect upon human societies is a different story.
JCHsays
My question with CO2 injection is whether or not it is continuous ~2.6XCO2, or whether it bounces between a lower number, say 400 ppm, and 1,000 ppm?
[Response:800 ppm or so is a typical target, don’t know about diurnal variation or regulation.]
The advice on the site to which Dan H. linked recommends just 2 hours of CO2 injection on days when it’s okay to open the glass, so the economic value of the difference between 390 ppm and 1,000 ppm may not be very high.
The difference between 390 ppm and ~150 ppm would have a significant economic benefit.
Lynn Vincentnathansays
Here’s another supposed disproof of current AGW (tho I’m not sure how it disproves it):
“Multiproxy summer and winter surface air temperature field reconstructions for southern South America covering
the past centuries,” R. Neukom, et al. 2011. Climate Dynamics
Volume 37, Numbers 1-2, 35-51.
Abstract: We statistically reconstruct austral summer (winter) surface air temperature fields back to AD 900 (1706) using 22 (20) annually resolved predictors from natural and human archives from southern South America (SSA). This represents the first regional-scale climate field reconstruction for parts of the Southern Hemisphere at this high temporal resolution. We apply three different reconstruction techniques: multivariate principal component
regression, composite plus scaling, and regularized expectation maximization. There is generally good agreement between the results of the three methods on interannual and decadal timescales. The field reconstructions allow us to describe differences and similarities in the temperature evolution of different sub-regions of SSA. The
reconstructed SSA mean summer temperatures between 900 and 1350 are mostly above the 1901–1995 climatology. After 1350, we reconstruct a sharp transition to colder conditions, which last until approximately 1700. The summers in the eighteenth century are relatively warm with
a subsequent cold relapse peaking around 1850. In the twentieth century, summer temperatures reach conditions similar to earlier warm periods. The winter temperatures in the eighteenth and nineteenth centuries were mostly below the twentieth century average. The uncertainties of our reconstructions are generally largest in the eastern lowlands of SSA, where the coverage with proxy data is
poorest. Verifications with independent summer temperature proxies and instrumental measurements suggest that the interannual and multi-decadal variations of SSA temperatures are well captured by our reconstructions. This new dataset can be used for data/model comparison and data assimilation as well as for detection and attribution studies at sub-continental scales.
RE the discussion about “CO2, we call it life,” – I studied it a bit & included something about it in a paper on food rights and climate change which will be coming out this year:
First we need to address the argument that elevated carbon dioxide levels increase crop production. Aside from this being disingenuous because the CO2 is also causing warming and other effects that could be harmful to crops, there is evidence that increasing CO2 will not help crops as much as expected, and may even harm some crops and sea life, never mind the warming (Cline 2007: 23-26). While earlier enclosed studies showed increased growth with added CO2, recent open field studies show less increase and even a decline of some crops (Long, et al. 2006, Cruz, et al. 2007: 480). Furthermore, crops were found to be less nutritious (Högy, et al. 2009), and had greater pest damage (Hunter 2001). In the real world, crop growth is affected by many factors beyond CO2, including other nutrients, water supply, climate, extreme weather events, soil moisture, toxins expected to increase with global warming, and soil acidification from CO2 (Oh and Richter 2004). So while CO2 may moderately enhance crops up to a point, these other factors are expected to limit the potential enhancement and even lead to eventual declines. When the impact of warming is considered, a nonlinear relationship regarding crop productivity has been found for mid and high latitudes — the U.S., Canada, Europe, Russia, Japan and Northern China — with increased yields projected up to around 2050, after which the warming causes sharp decrease (Schlenker and Roberts 2009). A more recent study has found that climate change has already reduced some crops globally, despite CO2 fertilization and improved technology (Lobell, et al. 2011). As for sea life, an important human food supply, CO2-caused ocean acidification is having negative impacts on zooplankton (at the base of the food chain), shellfish, fish, and coral reefs, home to one-fourth of sealife (Rogers and Laffoley 2011; Doney, et al. 2009; Hoegh-Guldberg, et al. 2007; Munday, et al. 2010).
REFERENCES
– Cline, W. R. 2007. Global Warming and Agriculture. Washington, DC: Center for Global Development and the Peterson Institute for International Economics.
– Cruz, R. V., H. Harasawa, M. Lal, S. Wu, Y. Anokhin, B. Punsalmaa, Y. Honda, M. Jafari, C. Li, and N. Huu Ninh. 2007. “Asia.” Climate Change 2007: Impacts, Adaptation and Vulnerability. Contributions of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. M. L. Parry, O. F. Canziani, J. P. Palutikof, P. J. van der Linden, and C. E. Hanson (eds.). Cambridge, UK: Cambridge University Press, pp. 469-506.
– Doney, S. C., V. J. Fabry, R. A. Feely, and J. Kleypas. 2009. Ocean Acidification: The Other CO2 Problem. Annual Review of Marine Sciences 1: 169-192.
– Hoegh-Guldberg, O., P. J. Mumby, A. J. Hooten, R. S. Steneck, and E. G. P. Greenfield, C. D. Harvell, P. F. Sale, A. J. Edwards, K. Caldeira, N. Knowlton, C. M. Eakin, R. Iglesias-Prieto, N. Muthiga, R. H. Bradbury, A. Dubi, M. E. Hatziolos. 2007. Coral reefs under rapid climate change and ocean acidification. Science 318(5857): 1737-1742.
– Högy, P., H. Wieser, P. Köhler, K. Schwadorf , J. Breuer, J. Franzaring, R. Muntifering and A. Fangmeier. 2009. “Effects of elevated CO2 on grain yield and quality of wheat: results from a 3-year free-air CO2 enrichment experiment.” Plant Biology 11: 60-69.
– Hunter, M. D. 2001. “Effects of Elevated Atmospheric Carbon Dioxide on Insect-Plant Interactions.” Agricultural and Forest Entomology 3: 153-159.
– Lobell, D. B., W. Schlenker, and J. Costa-Roberts. 2011. “Climate Trends and Global Crop Production Since 1980.” Science 333(6042): 616-620.
– Long, S. P., E. A. Ainsworth, A. D. B. Leakey, J. Nösberger, D. R. Ort. 2006. “Food for Thought: Lower-Than-Expected Crop Yield Stimulation with Rising CO2 Concentrations.” Science 312(5782): 1918-1921.
– Munday, P. L., D. L. Dixson, M. I. McCormick, M. Meekan, M. C. O. Ferrari, and D. P. Chivers. 2010. “Replenishment of fish populations is threatened by ocean acidification.” Proceedings of the National Academy of Sciences 107(29):12930-12934.
– Oh, N-H., and D. D. Richter, Jr. 2004. “Soil acidification induced by elevated atmospheric CO2” Global Change Biology 10.11: 1936-1946.
– Oschlies, A., K. Schulz, U. Riebesell, and A. Schmittner. 2008. “Simulated 21st century’s increase in oceanic suboxia by CO2-enhanced biotic carbon export” Global Biochemical Cycles 22: 1-10.
– Schlenker, W., and M. Roberts. 2009. “Nonlinear Temperature Effects Indicate Severe Damages to U.S. Crop Yields under Climate Change.” Proceedings of the National Academy of Science. 106(37): 15594-15598.
“As I have said before, there are two types of demographers–Malthusians and those who are bad at math.” – Ray Labdury
Yes, you’ve said it many times, and it’s been wrong every time you’ve said it. Malthus, unsurprisingly, did not know what the effects of urbanisation and improving the status and education of women would be, and he had a horror of contraception. He would find the rapid fall in birth rates over the past half-century astonishing.
Re sea level rise: I’ve now finished my part of a coauthored book on this subject and think we have covered all the bases at an introductory level. I haven’t read anything radically new and dramatic on sea level rise for at least the last three months. If you have, please tell me what you found.
Hughsays
Hi Gavin, et al, I was having a discussion/altercation with one of those “experts” the internet alchemically generates (opinionated blowhard goes in, expert on everything comes out) who asserted that the amount of heat generated by the physical process of burning fossil fuels was “thousands of times greater” than that trapped by the resultant CO2-enhanced greenhouse effect. He was one of those bore who thinks that global warming violates the Second Law of Thermodynamics (and mass-energy conservation, somehow), but regardless, I was wondering if there was a way of calculating the effect, however insignificant, on the planet’s average temperature of such inputs? I imagine internal climate variability makes it impossible to directly observe, but maybe an equation?
“At the end of the last Ice Age, there was a great increase in seismicity along the margins of the ice sheets in Scandinavia and places like this, and that triggered these huge submarine landsides which generated tsunamis,” McGuire said. “So you’ve got the whole range of geological hazards there that can result from if we see this big catastrophic melting.”
McGuire conducted a study that was published in the journal Nature in 1997 that looked at the connection between the change in the rate of sea level rise and volcanic activity in the Mediterranean for the past 80,000 years and found that when sea level rose quickly, more volcanic eruptions occurred, increasing by a whopping 300 percent. http://www.livescience.com/7366-global-warming-spur-earthquakes-volcanoes.html
Hugh @230
Your question requires a calc that I have seen done before but I obviously wasn’t paying much attention because I don’t remember the answer at all. So I’ll tap out my workings here just in case I make a mistake (which is something I’m quite good at doing).
Calorific value of a ton of carbon (ie anthracite =almost solid carbon) = 36 GJ. Natural gas would release about double that with its hydrogen content, so call it 72 GJ/tC
Double atmospheric CO2 (giving forcing of 4 W/sq m of earth) requires 270ppm x 2.13 GtC in atmosphere. Emissions required would be double the atmospheric increase.
So multiplying it out (72 x 270 x 2.13 x 2 x 10^18) and dividing by the 4 W/sq m gives energy release to raise global forcing 1 W/sq m = 2 x10^22 J The world is 510 million sq km so working that through you get ( / (5.1E14 x 60 x60 x24) = very approximately 470 days to trap the energy equal to that released by burning.
If you want an answer in thousands, try 11,000 hours. It would be half that for coal & somewhere inbetween for oil.
Hopefully, if I’ve divided by a numerator or stuck a decimal point upside down, someone will come to my rescue.
“Annual global energy consumption is about .5 zettajoules. . .” (1 ZJ = 10e21 Joules.)
However, a yottajoule is 10e24, and is approximately the amount of energy needed to warm all the planet’s water 1 degree C. Looks like direct heating is just way, way too small to account for observed warming–especially when you consider that absorbed solar energy is about 3.85 YJ.
Ray Ladburysays
Nick Gotts, Malthus was a son of a bitch, a heartless apologist for privilege. However, his fundamental insight–that popultions cannot grow indefinitely without outstripping available resources–was correct. That there was much he did not understand about growth of human populations does not invalidate this insight.
Human populations continued to grow in Europe largely as a result of new foodstuffs from the New World, increased mechanization and improved farming techniques, all of which increased calories per acre. We averted disaster again in the 50s and 60s when the green revolution discovered how we could eat petroleum by turning it into corn and soy. We may even avert disaster yet again by means of genetically modified crops. However, each of these circumventions depletes scarce, one-time windfalls–fossil fuels, soil fertility, aquifers that once dry will never flow again, and fisheries that are being turned to aquatic deserts. What do you think that does to the carrying capacity of the planet? How do you envision us moving from 9-10 billion in 2050 or even 15 billion in 2100 to a sustainable population of perhaps 1 billion (given the environmental damage we’ve done)?
Ray Ladburysays
Hugh@230,
Your Internet correspondent is an idiot. Even the most cursory search of the web is sufficient to show him he is wrong.
Terry richardsonsays
Sorry to be OT on this thread but can you comment on yesterday’s NY Times article reviewing a proposal which appeared in SCIENCE which would 1) attack “black soot” and methane mainly 2) allegedly lower avg temp by 1 degree by 2050?
Again, sorry to be OT on this particular thread. I think people take you as a very credible and sober voice in all this and look to you to help them parse the latest AGW headlines.
I suggest that folks opining that Malthus was “wrong” might wish to be specific as to what they think Malthus was “wrong” about.
It is hard to see how Malthus’s “fundamental insight”, to use Ray Ladbury’s words, that “populations cannot grow indefinitely without outstripping available resources” could be “wrong”.
And the fact that the human species has been able to continue growing by exploiting fossil fuels certainly doesn’t invalidate that insight.
On the other hand, to the extent that Malthus argued that populations WILL and MUST inevitably grow until they outstrip available resources and crash, MAY prove to be “wrong”, IF humans prove able to voluntarily reduce and maintain our population at a sustainable level — although that remains to be seen.
Slight correction, Ray–“enough to show Hugh he is wrong.” For “him,” I’m not so sure that ‘enough’ exists.
Yeah, I know–I was the one decrying snark, a while back. Sigh.
Nick Gottssays
“However, his fundamental insight–that popultions cannot grow indefinitely without outstripping available resources–was correct.” – Ray Ladbury
His fundamental claims were that population increases geometrically while food supply increases arithmetically – both specifically mathematical claims which have up to now been quite wrong. This is what makes your claim that non-Malthusian demographers are “bad at math” so absurd.
In his earlier work, he also claimed that population growth would only be checked by food shortage – also wrong. He later made a minor correction to this, allowing for the possibility of “moral restraint” i.e. that people would limit their families by not having sex. Wrong again. I don’t mean to disparage him as a social scientist – he was certainly the pioneer of demography; but like most scientific pioneers, he made a lot of mistakes.
Ray Ladburysays
Nick,
Has population growth been “checked”. Last I saw, we were on track for ~10 billion by 2050, and the research that claims that will be a maximum is pure extrapolation.
Darwin made mistakes as well. And as demographers seem to fall into either Malthusians or Cornucopians, I leave it to you to decide which is worse at math.
The fact remains, human population will not grow indefinitely. There is no convincing evidence that it will stop growing before it is forced to do so catastrophically.
Ray Ladburysays
SA,
For all the gray matter we have in our heads, our demographics have been as unregulated and irrational as the population biology of a yeast colony in a bottle of beer. I rather doubt that the product our our demise will be nearly as useful.
John E. Pearsonsays
Given that we live in a world where a man whose sole publication in a peer-reviewed scientific journal is a decades old publication claiming that kissing spreads HIV (http://scholar.google.com/scholar?hl=en&q=Monckton+kissing&btnG=Search&as_sdt=0%2C32&as_ylo=&as_vis=0) is now taken, by the non-scientific public, seriously as a climate scientist and that, to leading order, we’ve done nothing to reduce emissions this rates as among the most hopeful news of the millennium for my grandchildren:
Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security
Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids 0.7 to 4.7 million annual premature deaths from outdoor air pollution and increases annual crop yields by 30 to 135 million metric tons due to ozone reductions in 2030 and beyond. Benefits of methane emissions reductions are valued at $700 to $5000 per metric ton, which is well above typical marginal abatement costs (less than $250). The selected controls target different sources and influence climate on shorter time scales than those of carbon dioxide–reduction measures. Implementing both substantially reduces the risks of crossing the 2°C threshold.
It’s pay-walled. Sorry about that. My recommendation? Pay for it. Or don’t. Your choice.
“Has population growth been “checked”.” – Ray Ladbury
Yes, in some countries it has. Worldwide, it has slowed very considerably.
“as demographers seem to fall into either Malthusians or Cornucopians”
No, they don’t. Most demographers do not actually spend their time making projections of global population growth at all, as you can readily confirm for yourself by putting “demography” into Google Scholar. Those who do, do not fall readily into your simplistic categories.
“Darwin made mistakes as well.”
As I said in the comment directly before yours, which you don’t appear to have read:
“I don’t mean to disparage him [Malthus] as a social scientist – he was certainly the pioneer of demography; but like most scientific pioneers, he made a lot of mistakes.”
“There is no convincing evidence that it will stop growing before it is forced to do so catastrophically.”
Well no, provided you ignore half a century of falling growth rates worldwide, and the fact that quite a number of countries now have fertility rates that will lead to population decline in the near future. We also know the main factors that lead to declining birth rates: improving the status and education of women, greater availability of contraception, urbanization, and possibly rising real incomes. Mass urbanization is going to happen anyway; the other factors – particularly the first two – are what we should focus on. But declaring in advance, and in the face of the evidence, that we cannot succeed, is both completely unsupported by the evidence, and grossly irresponsible.
Ray Ladburysays
Nick,
I did read your post. What you ignore are the facts that causes of the falling birthrates all involve unsustainable increases in resource consumption or other trends that are unsustainabloe or that are doubtful in their application outside of the industrial portion of the globe.
The religions of nearly half the planet’s population oppose contraception. We have a presidential candidate here in the US who has promised to greatly restrict if not end contraception in the us–and he has not been laughed off the stage. Education of women is absolutely essential to reduction of fertility rates, and yet it is stagnating in many of the countries with the fastest growing populations.
How do you think aid programs will fare as the US and Europe tighten budgets? Frankly, I think we could stabilize global population and resolve climate change and develop a sustainable energy infrastructure before 2050 without any sort of draconian measures. I just think humans are too stupid to do so. The problem is that we are dependent on the bottom 50% of the IQ curve–The Revenge of the C Students.
Dan H.says
On a seperate note, Judith Curry has started a discussion based on presenations given by Gavin Schmidt and Richard Betts.
#199–“Names appearing on this blog’s roll-call put in the shade any peer review. . .”
Hardly the point. It isn’t who does the looking, it’s the skill, talent and commitment with which the looking is done. In peer review, there is an implicit commitment to take the ideas seriously, and to examine (quite often in a mode rather like destructive testing) how ‘robust’ they are.
It sounds to me as if what you are saying is that you have a hobby, and you like it the way it is. Nothing wrong with that. But it’s not likely to shake the world (or any subset thereof.)
Just saying.
Dan H. – what does it mean when you say a greenhouse has CO2 at 1000 ppm? In my experience it means CO2 will not, hopefully, drop to a limiting level ppm and suspend uptake. This is something that never happens, that I know of, in a cornfield – not in 1812, not in 1912, and not in 2012.
Dan H.,
I’m gonna go out on a limb and guess that you aren’t a gardener. If you were, you would realize that the important thing is NOT whether CO2 promotes growth of plants, but whether it promotes growth of the plants we need to support a population of 9-10 billion by 2050.
All indications are that rising temperatures reduce grain yields–especially of rice and winter wheat.
Do not confuse fetid with fertile.
Vukcevic,
A blog post and comments cannot substitute for a detailed review by experts. As scientists, reviewing work within our expertise is part of our day job (albeit, usually an unpaid part). You simply will not get the sort of detail in a blog comment that you do in a peer review.
Then, too, there is the problem of sorting the wheat from the chaff. How do you know the commenter could actually find his ass with both hands and a GPS on the subject matter? The intertubes are full of bullshitters and wannabes. An expert sees through them pretty easily, but they can do a convincing immitation if you are not expert inthe subject matter.
This is not to say that peer review is perfect. The reviewers have the imprimatur of the editors, but both sometimes make mistakes. That is why the ultimate stamp of approval comes when your colleagues–even if they are brand new colleagues–realize the usefulness of the ideas, data or methods you introduce. This is my definition of scientific consensus. Scince–it works, and there is a reason why it works the way it does.
Dan rebunks.
# 199 vukcevic
…Names appearing on this blog’s roll-call put in the shade any peer review,…..
roll-call is on this page
….an inquisitive reader or poster of this blog.
is occasionally but not too often found here
JCH,
Here is just one example of greenhouse CO2 concentrations (some recommendation higher).
http://www.advancegreenhouses.com/use_of_co2_in_a_greenhouse.htmecommended greenhouse concentrations of CO2.
Ray,
Yes, I am a gardener, but only small time. My father grew up in Iowa, and I experienced many a farm there. Whether we can grow enought food to support the population of 2050 is a whole different question. Paul Ehrlich feared that mass starvation would occur starting in the 1970s due to overpopulation. Agricultural advances since then have increased food production to ease these fears. Feeding the future population may require further advances. Knowing how plants grow in an atmosphere with higher CO2 concentrations will certainly aid these developments. For examplee, see these experiments on wheat.
http://usda.academia.edu/SAnapalli/Papers/1045898/Simulation_of_free_air_CO2_enriched_wheat_growth_and_interactions_with_water_nitrogen_and_temperature
[Response: Maybe it’s just me, but if I had an agenda I was trying to push when citing a scientific paper, I think I would at least read say, the abstract, so that I knew how representative it was, or at least what it’s major focus was, or failing those, that it at least didn’t contradict my position. Crazy eh?–Jim]
Here’s a new one denialists are using, with a horizontal sine wave of temps on into the future; what is the scientific response to this:
“Testing an astronomically based decadal-scale empirical harmonic climate model versus the IPCC (2007) general circulation climate models,” Nicola Scafetta
http://www.sciencedirect.com/science/article/pii/S1364682611003385
[Response: This is just another curve fit with no predictability. The analysis of the GCMs assumes (completely incorrectly) that all climate variability in them is forced and is misconceived from the get-go. Even volcanic impacts are ignored in favor of celestial forcings that are more akin to astrology than science. An embarrassment to the author and the journal. – gavin]
Dan H – greenhouses worked very well before enhanced CO2 fertilization. The sequence was not: we just invented this CO2 enhancement equipment, what we need now is some sort of glass enclosure.
The site says that when windows are open, 390 ppm, the enhancement should be done for just two hours. Does this strike you as odd? When it’s 400 ppm outside, will the two hours drop to one and a half hours?
Doing an unscientific review of some of the many papers re: CO2 and N (some of which appear conflicting). Here’s a list authors I found.
Ainsworth
Balab
Ban-Weiss
Bernacchi
Caldeiraa
Calfapietra
Caoa
Ciais
Czimczik
Dahlgren
Friend
Hietz
Houlton
Lagomarsino
Leakey
Long
Loreto
Lukac
Morford
Nemanid
Nock
Ort
Prieur
Richter
Rogers
Townsend-Small
Turner
Wanek
Wang
Wright
Zaehle
Only one name, Benjamin Z. Houlton, appeared twice. One wonders if these people talk to each other.
Anyway, I wonder if it might be possible for RC to invite the lead authors of the FACE study to do a guest editorial. What they found and what still remains unknown. Might clear up some confusion.
Re:Boyce paper in Nature claiming phytoplankton decrease
Please note the brief communications commenting on this paper. The finding does not appear to be robust.
Paul Ehrlich failed to anticipate that humans would learn to survive by eating petroleum–with the intermediate step of turning it into corn and soy, and in the process hastening the depletion of not just this one-time windfall, but also aquifers, water quality and soil fertility.
As I have said before, there are two types of demographers–Malthusians and those who are bad at math.
#208 Lynn Vincentnathan
I still can’t believe that no one has done a correlation study of earthquakes on Pluto to climate change on Earth.
Just imagine, the magical wonders of curve fitting producing fanciful results to titillate the minds of those that don’t want to know…
RE #208, thanks for your response, Gavin — it was duly transmitted to the said skeptics.
I pointed out before your response that if this were so — planetary harmonic impacts on climate — then that would not overturn the laws of physics on which the GH effect was based, so it would be similar to the solar irradiation cycles — in the troughs, we might expect some cooling or only slight warming, considering the impact of AGW, and in the peaks we would expect the AGW to piggy back on the other warming and really put us in deep do-do.
#200 Dan H.
To compliment #203 Ray Ladbury, crop yield production is already significant in the numbers in relation to thermal limits, and in context of increased RF/temp. Changes in atmospheric hydrology will increasingly to impact crop productivity as well as soil moisture drop and temperature will increase acres burned and result in increasing crop loss.
AGU Fall Meeting Video Dec. 2011
http://www.youtube.com/watch?v=gBOnsG5bSAk
[When I tried clicking it it started in the middle ??? so if that happens just click in the timeline at the beginning. Chris Field does an excellent overview on these issues.]
NPP data indicates that it really doesn’t matter that much though. What good does it do to have larger plants form increased CO2 if the plants burn up so you never even have a chance to eat them?
ETH Zürich, 2010
http://www.youtube.com/watch?v=9S54NcYt_ww
Boyce article followup — three brief communication comments and reply (excerpts, Nature’s paywalled):
http://www.nature.com/nature/journal/v472/n7342/full/nature09953.html
This is science at work, comparing remote sensing of chlorophyll with onsite sampling and with secchi disk (how transparent the water is) records.
Another recent paper:
http://iopscience.iop.org/1748-9326/6/3/034035/
M Hofmann et al 2011 Environ. Res. Lett. 6 034035
doi:10.1088/1748-9326/6/3/034035
Declining ocean chlorophyll under unabated anthropogenic CO2 emissions
“… numerical simulations reveal only weak reductions in chlorophyll(a) concentrations during the twentieth century, but project a 50% decline between 2000 and 2200. We identify a local and a remotely acting mechanism for this reduction in the North Atlantic …”
For Ray and Hank, more appropriate here than on the methane model thread, the always interesting CBC program Quirks and Quarks today had a piece with Dr Drew Shindell about human caused methane releases and black carbon/soot effects on climate [scroll to the bottom, should be able to listen]. The discussion concerned this study, a partial solution for society to try to limit the damage.
Re, Hank Roberts
The study is related to this 2010 finding: Phytoplankton Population Drops 40 Percent Since 1950
Researchers find trouble among phytoplankton, the base of the food chain, which has implications for the marine food web and the world’s carbon cycle http://www.scientificamerican.com/article.cfm?id=phytoplankton-population
And it appears that the new study is a bit too conservative? For instance no methane forcing and current emission scenario incorporated. So i don’t see why ocean chlorophyll and following phytoplankton decline should not go even lower.
“We explore these questions using an ocean general circulation model forced with documented historic and projected future anthropogenic emissions of carbon dioxide according to the IPCC SRES A1FI emission scenario until the year 2100. We further extend the time period covered by the A1FI scenario by assuming a linear decline in emissions from 2100 to 2200 and keeping them at zero levels until 2400.”
Dan@200:
What the ˙©¥ƒ†∂®´∑≈ are you talking about?
I have just completed building a $15,000+ greenhouse.
One of the most important things about a greenhouse is how to accomplish air exchange without affecting the temperature or humidity too much (I used my own design, based on lots of input from knowledgeable friends, and the requirements of the species of plants I intend to grow). As plants metabolize CO2, they release oxygen. If this oxygen is not carried away and replaced by more CO2 at a sufficient rate (which varies substantially depending on species), the plants will suffer. Air circulation and exchange is vital. For this reason, greenhouses DO NOT have high levels of CO2, unless someone is intentionally injecting CO2 into them. They have at most the level of CO2 of the air that is being exchanged. How could they possibly have more? What would be generating the CO2?
[Response:He’s talking about artificial enhancement to ~ doubled levels that some production greenhouses use to speed growth.–Jim]
No one is dismissing anything except your faulty logic.
Top five climate science points for 2011:
1. Dr Hansen says warming imbalance for the last 5-6 years is about +0.6W/m2.
2. Dr Trenberth says that it is still about +0.9W/m2 confirmed by models.
3. Dr Hansen says that the reduction is due to Chinese aerosols.
4. Dr Trenberth says that he does not believe that for a minute and the missing heat is still to be found in the oceans.
5. Professor CERES is still reading the imbalance at +6.4W/m2.
Well, I have been to A LOT of greenhouses, and the “typical greenhouse,” as Dan called it, does not inject CO2. CO2 injection will only work well in colder climates, as air exchange must be discontinued for CO2 injection to be beneficial. If there is no air exchange, then the cost of cooling the greenhouse increases substantially. Greenhouses are not closed systems.
Here in Texas, a closed greenhouse during the day is extremely expensive to keep cool during much of the year. And since AGW is making temperatures warmer, that problem is getting worse, not better.
[Response:Right, not an option in any warm climate, even with whitewash applied.]
My point is that while CO2 has an effect on plants, and while that effect is worth understanding, there is no credible evidence that increased atmospheric CO2 will be beneficial for human societies on the whole, and there is plenty of credible evidence that just the opposite is most likely.
Craig,
In your specific case, the practice may not be efficient. Here, in the “colder climates” it works quite well, as you maintain. No one ever implied that the greenhouse was a “closed system.”
The whole previous discussion was about the CO2 effect upon plants. The effect upon human societies is a different story.
My question with CO2 injection is whether or not it is continuous ~2.6XCO2, or whether it bounces between a lower number, say 400 ppm, and 1,000 ppm?
[Response:800 ppm or so is a typical target, don’t know about diurnal variation or regulation.]
The advice on the site to which Dan H. linked recommends just 2 hours of CO2 injection on days when it’s okay to open the glass, so the economic value of the difference between 390 ppm and 1,000 ppm may not be very high.
The difference between 390 ppm and ~150 ppm would have a significant economic benefit.
Here’s another supposed disproof of current AGW (tho I’m not sure how it disproves it):
RE the discussion about “CO2, we call it life,” – I studied it a bit & included something about it in a paper on food rights and climate change which will be coming out this year:
http://blogs.nature.com/soapboxscience/2012/01/06/climate-change-and-extreme-events
“As I have said before, there are two types of demographers–Malthusians and those who are bad at math.” – Ray Labdury
Yes, you’ve said it many times, and it’s been wrong every time you’ve said it. Malthus, unsurprisingly, did not know what the effects of urbanisation and improving the status and education of women would be, and he had a horror of contraception. He would find the rapid fall in birth rates over the past half-century astonishing.
re: 227
Malthus is the most patient of men.
Re sea level rise: I’ve now finished my part of a coauthored book on this subject and think we have covered all the bases at an introductory level. I haven’t read anything radically new and dramatic on sea level rise for at least the last three months. If you have, please tell me what you found.
Hi Gavin, et al, I was having a discussion/altercation with one of those “experts” the internet alchemically generates (opinionated blowhard goes in, expert on everything comes out) who asserted that the amount of heat generated by the physical process of burning fossil fuels was “thousands of times greater” than that trapped by the resultant CO2-enhanced greenhouse effect. He was one of those bore who thinks that global warming violates the Second Law of Thermodynamics (and mass-energy conservation, somehow), but regardless, I was wondering if there was a way of calculating the effect, however insignificant, on the planet’s average temperature of such inputs? I imagine internal climate variability makes it impossible to directly observe, but maybe an equation?
Re: population
Population of world ‘could grow to 15bn by 2100’
http://www.guardian.co.uk/world/2011/oct/22/population-world-15bn-2100
Speaking of CO2, here is something that I would have never suspected:
http://www.physorg.com/news/2012-01-carbon-dioxide-affecting-fish-brains.html
Re Hunt Janin
“At the end of the last Ice Age, there was a great increase in seismicity along the margins of the ice sheets in Scandinavia and places like this, and that triggered these huge submarine landsides which generated tsunamis,” McGuire said. “So you’ve got the whole range of geological hazards there that can result from if we see this big catastrophic melting.”
McGuire conducted a study that was published in the journal Nature in 1997 that looked at the connection between the change in the rate of sea level rise and volcanic activity in the Mediterranean for the past 80,000 years and found that when sea level rose quickly, more volcanic eruptions occurred, increasing by a whopping 300 percent. http://www.livescience.com/7366-global-warming-spur-earthquakes-volcanoes.html
and ofc
Climate forcing of geological and geomorphological hazards http://rsta.royalsocietypublishing.org/content/368/1919/2311.short?rss=1
[Climate Action] A great way to help bring awareness to the topic of climate change, to wear a Tshirt with related content. http://climateforce.net/2012/01/17/climate-action-tshirts-eu-usa/
for Hugh:
google: site:realclimate.org “waste heat”
will find several of the places Gavin has answered that; try
https://www.realclimate.org/index.php/archives/2009/11/wheres-the-data/comment-page-1/#comment-145234
Jeffrey Davis,
Malthus is dead, wrong, and dead wrong.
Hugh @230
Your question requires a calc that I have seen done before but I obviously wasn’t paying much attention because I don’t remember the answer at all. So I’ll tap out my workings here just in case I make a mistake (which is something I’m quite good at doing).
Calorific value of a ton of carbon (ie anthracite =almost solid carbon) = 36 GJ. Natural gas would release about double that with its hydrogen content, so call it 72 GJ/tC
Double atmospheric CO2 (giving forcing of 4 W/sq m of earth) requires 270ppm x 2.13 GtC in atmosphere. Emissions required would be double the atmospheric increase.
So multiplying it out (72 x 270 x 2.13 x 2 x 10^18) and dividing by the 4 W/sq m gives energy release to raise global forcing 1 W/sq m = 2 x10^22 J The world is 510 million sq km so working that through you get ( / (5.1E14 x 60 x60 x24) = very approximately 470 days to trap the energy equal to that released by burning.
If you want an answer in thousands, try 11,000 hours. It would be half that for coal & somewhere inbetween for oil.
Hopefully, if I’ve divided by a numerator or stuck a decimal point upside down, someone will come to my rescue.
#230, #237–
Another comparison, based upon: http://en.wikipedia.org/wiki/Joule
“Annual global energy consumption is about .5 zettajoules. . .” (1 ZJ = 10e21 Joules.)
However, a yottajoule is 10e24, and is approximately the amount of energy needed to warm all the planet’s water 1 degree C. Looks like direct heating is just way, way too small to account for observed warming–especially when you consider that absorbed solar energy is about 3.85 YJ.
Nick Gotts, Malthus was a son of a bitch, a heartless apologist for privilege. However, his fundamental insight–that popultions cannot grow indefinitely without outstripping available resources–was correct. That there was much he did not understand about growth of human populations does not invalidate this insight.
Human populations continued to grow in Europe largely as a result of new foodstuffs from the New World, increased mechanization and improved farming techniques, all of which increased calories per acre. We averted disaster again in the 50s and 60s when the green revolution discovered how we could eat petroleum by turning it into corn and soy. We may even avert disaster yet again by means of genetically modified crops. However, each of these circumventions depletes scarce, one-time windfalls–fossil fuels, soil fertility, aquifers that once dry will never flow again, and fisheries that are being turned to aquatic deserts. What do you think that does to the carrying capacity of the planet? How do you envision us moving from 9-10 billion in 2050 or even 15 billion in 2100 to a sustainable population of perhaps 1 billion (given the environmental damage we’ve done)?
Hugh@230,
Your Internet correspondent is an idiot. Even the most cursory search of the web is sufficient to show him he is wrong.
Sorry to be OT on this thread but can you comment on yesterday’s NY Times article reviewing a proposal which appeared in SCIENCE which would 1) attack “black soot” and methane mainly 2) allegedly lower avg temp by 1 degree by 2050?
Again, sorry to be OT on this particular thread. I think people take you as a very credible and sober voice in all this and look to you to help them parse the latest AGW headlines.
Best wishes.
http://www.nytimes.com/2012/01/17/science/countering-climate-change-without-waiting-for-a-payoff.html?_r=1
[moved]
I suggest that folks opining that Malthus was “wrong” might wish to be specific as to what they think Malthus was “wrong” about.
It is hard to see how Malthus’s “fundamental insight”, to use Ray Ladbury’s words, that “populations cannot grow indefinitely without outstripping available resources” could be “wrong”.
And the fact that the human species has been able to continue growing by exploiting fossil fuels certainly doesn’t invalidate that insight.
On the other hand, to the extent that Malthus argued that populations WILL and MUST inevitably grow until they outstrip available resources and crash, MAY prove to be “wrong”, IF humans prove able to voluntarily reduce and maintain our population at a sustainable level — although that remains to be seen.
Slight correction, Ray–“enough to show Hugh he is wrong.” For “him,” I’m not so sure that ‘enough’ exists.
Yeah, I know–I was the one decrying snark, a while back. Sigh.
“However, his fundamental insight–that popultions cannot grow indefinitely without outstripping available resources–was correct.” – Ray Ladbury
His fundamental claims were that population increases geometrically while food supply increases arithmetically – both specifically mathematical claims which have up to now been quite wrong. This is what makes your claim that non-Malthusian demographers are “bad at math” so absurd.
In his earlier work, he also claimed that population growth would only be checked by food shortage – also wrong. He later made a minor correction to this, allowing for the possibility of “moral restraint” i.e. that people would limit their families by not having sex. Wrong again. I don’t mean to disparage him as a social scientist – he was certainly the pioneer of demography; but like most scientific pioneers, he made a lot of mistakes.
Nick,
Has population growth been “checked”. Last I saw, we were on track for ~10 billion by 2050, and the research that claims that will be a maximum is pure extrapolation.
Darwin made mistakes as well. And as demographers seem to fall into either Malthusians or Cornucopians, I leave it to you to decide which is worse at math.
The fact remains, human population will not grow indefinitely. There is no convincing evidence that it will stop growing before it is forced to do so catastrophically.
SA,
For all the gray matter we have in our heads, our demographics have been as unregulated and irrational as the population biology of a yeast colony in a bottle of beer. I rather doubt that the product our our demise will be nearly as useful.
Given that we live in a world where a man whose sole publication in a peer-reviewed scientific journal is a decades old publication claiming that kissing spreads HIV (http://scholar.google.com/scholar?hl=en&q=Monckton+kissing&btnG=Search&as_sdt=0%2C32&as_ylo=&as_vis=0) is now taken, by the non-scientific public, seriously as a climate scientist and that, to leading order, we’ve done nothing to reduce emissions this rates as among the most hopeful news of the millennium for my grandchildren:
Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security
Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids 0.7 to 4.7 million annual premature deaths from outdoor air pollution and increases annual crop yields by 30 to 135 million metric tons due to ozone reductions in 2030 and beyond. Benefits of methane emissions reductions are valued at $700 to $5000 per metric ton, which is well above typical marginal abatement costs (less than $250). The selected controls target different sources and influence climate on shorter time scales than those of carbon dioxide–reduction measures. Implementing both substantially reduces the risks of crossing the 2°C threshold.
It’s pay-walled. Sorry about that. My recommendation? Pay for it. Or don’t. Your choice.
http://www.sciencemag.org/content/335/6065/183
“Has population growth been “checked”.” – Ray Ladbury
Yes, in some countries it has. Worldwide, it has slowed very considerably.
“as demographers seem to fall into either Malthusians or Cornucopians”
No, they don’t. Most demographers do not actually spend their time making projections of global population growth at all, as you can readily confirm for yourself by putting “demography” into Google Scholar. Those who do, do not fall readily into your simplistic categories.
“Darwin made mistakes as well.”
As I said in the comment directly before yours, which you don’t appear to have read:
“I don’t mean to disparage him [Malthus] as a social scientist – he was certainly the pioneer of demography; but like most scientific pioneers, he made a lot of mistakes.”
“There is no convincing evidence that it will stop growing before it is forced to do so catastrophically.”
Well no, provided you ignore half a century of falling growth rates worldwide, and the fact that quite a number of countries now have fertility rates that will lead to population decline in the near future. We also know the main factors that lead to declining birth rates: improving the status and education of women, greater availability of contraception, urbanization, and possibly rising real incomes. Mass urbanization is going to happen anyway; the other factors – particularly the first two – are what we should focus on. But declaring in advance, and in the face of the evidence, that we cannot succeed, is both completely unsupported by the evidence, and grossly irresponsible.
Nick,
I did read your post. What you ignore are the facts that causes of the falling birthrates all involve unsustainable increases in resource consumption or other trends that are unsustainabloe or that are doubtful in their application outside of the industrial portion of the globe.
The religions of nearly half the planet’s population oppose contraception. We have a presidential candidate here in the US who has promised to greatly restrict if not end contraception in the us–and he has not been laughed off the stage. Education of women is absolutely essential to reduction of fertility rates, and yet it is stagnating in many of the countries with the fastest growing populations.
How do you think aid programs will fare as the US and Europe tighten budgets? Frankly, I think we could stabilize global population and resolve climate change and develop a sustainable energy infrastructure before 2050 without any sort of draconian measures. I just think humans are too stupid to do so. The problem is that we are dependent on the bottom 50% of the IQ curve–The Revenge of the C Students.
On a seperate note, Judith Curry has started a discussion based on presenations given by Gavin Schmidt and Richard Betts.
http://judithcurry.com/2012/01/18/2-perspectives-on-communicating-climate-science/#more-6719