Both of these factors are weather events, not climate events:
The new findings show that a pregnant woman’s exposure to reduced precipitation and an increased number of very hot days indeed results in lower birth weight.
One wonders if they might find correlations to more days days with high rainfall (seasonal monsoon) and cold days (winter) as well, if they looked. As I understand biology, any stress like this in early development can show up later.
From the UNIVERSITY OF UTAH
Climate change negatively affects birth weight, University of Utah study finds
From melting glaciers to increasing wildfires, the consequences of climate change and strategies to mitigate such consequences are often a hotly debated topic. A new study led by the University of Utah adds to the ever-growing list of negative impacts climate change can have on humans–low birth weight.
The first of its kind, the two-year project led by U geography professor Kathryn Grace examined the relationship among precipitation, temperature and birth weight in 19 African countries. Grace and her team utilized high quality, detailed climate data in conjunction with extensive health data to focus on climate change and its effects on birth weight in the developing world.
The new findings show that a pregnant woman’s exposure to reduced precipitation and an increased number of very hot days indeed results in lower birth weight.
“Our findings demonstrate that in the very early stages of intra-uterine development, climate change has the potential to significantly impact birth outcomes. While the severity of that impact depends on where the pregnant woman lives, in this case the developing world, we can see the potential for similar outcomes everywhere,” said Grace.
The other authors are Frank Davenport, Heidi Hanson, Christopher Funk and Shraddhanand Shukla. The team reported the findings in Global Environmental Change. Christopher Funk (US Geological Survey) and UC Santa Barbara Climate Hazards Group provided the climate data used in the study, and have just detailed exceptional East African rainfall declines in a new paper in Nature Scientific Data.
Impacts of low birth weight are far-reaching
With the inaccuracy of determining exactly when a pregnancy began in rural countries which lack pregnancy tests and the inability to measure characteristics like a newborn’s cognitive development, low birth weight is the most reliable measure of whether a pregnancy has been negatively affected by an external factor. Low birth weight is defined by the World Health Organization as any baby born under 2,500 grams.
Low birth weight infants are more susceptible to illness, face a higher risk of mortality, are more likely to develop disabilities and are less likely to attain the same level of education and income as an infant born within a healthy weight range.
Consequently, the financial burden of a low birth weight infant can be significant. The costs of newborn intensive care unit stays and services, re-hospitalization and long-term morbidity can add up quickly, and in developing countries where such support services are less common and physical disability is considered a social stigma, low birth weight can be particularly impactful.
The first continent-wide analysis
In 2013, Grace and colleagues combined health data from Demographic and Health Surveys, which is funded by the United States Agency for International Development to collect and disseminate data on health and population in developing countries, and growing season data, with temperature and rainfall data from a variety of sources.
The team collected growing and livelihood zone information from the U.S. Agency for International Development’s Famine Early Warning System program and precipitation data from the Climate Hazards Group InfraRed Precipitation with Station data set.
In total, the team examined nearly 70,000 births in 19 African countries between 1986 and 2010 and matched these births with seasonal rainfall and air temperatures, as well as variables describing the mother and mother’s household, such as education level and whether the household had access to electricity.
This is the first time researchers utilized fine-resolution precipitation and temperature data alongside birth data to analyze how weather impacts birth weight.
To generate precipitation records for each birth, the team calculated the average precipitation for a given month within 10 km of the child’s birth location. This was done for each month up to one year prior to each child’s birth. The values were then summed over each trimester.
The same method was used to generate temperature records for each birth. The team first calculated the maximum daily temperature for a given calendar day within 10 km of a child’s birth location. From there, the number of days in each birth month where the temperature exceeded 105 F and 100 F as the maximum daily temperature were summed over trimesters.
Evidence and impact of climate change
The results show that an increase of hot days above 100 F during any trimester corresponds to a decrease in birth weight. In fact, just one extra day with a temperature above 100 F in the second trimester corresponded to a 0.9 g weight decrease; this result held with a larger effect when the temperature threshold was increased to 105 F.
Conversely, higher amounts of precipitation during any trimester resulted in larger birth weights. On average, a 10 mm increase in precipitation during a particular trimester corresponds to an approximate increase in birth weight of around 0.3-0.5 g.
“While the results are dependent on trimester and location, the data shows that climate change–a combination of increased hot days and decreased precipitation–correlate to lower birth weights,” said Grace.
“At the end of the day, the services we invest in to support these developing countries won’t reap the same level of benefits as long as climate change continues. Services such as education, clean water efforts and nutrition support won’t be as effective. We need to work faster and differently to combat the evident stresses caused by climate change.”
###
Note: within about 10 minutes of publication, this story was edited to correct a mistake – “seasonal drought” to “seasonal monsoon” with “high precipitation”
I started going bald in 1997…the very same year that the ” pause ” started !!!!! So is the ” pause ” responsible for my loss of hair ?? Who do I sue ????? I demand retribution !!! ( I need the money ) !!! LOL…
I started to lose my hair the same year Dr. Hansen turned the AC off in congress. I’m quite sure that teleconnections between the hot air in congress and my scalp are responsible for my hair lose.
Loss, hair loss.
Man I wish there was an edit option for comments.
Marcus,
It seems as logical to blame your follicles for The Great Pause.
I hope your follicles are not investigated under the wonderful mis-direction of RICO!
(Hmmm. Careful what you wish for . . . .)
Auto
Next up is parched throat, runny nose, and mild headaches.
I personally think my lack of hair is a much larger threat !!! Just think of all the bald heads reflecting all that sunlight !!! Oh , wait….never mind !!!
I’m going to sue you for increasing my local climate change with the glare from your bald spot, sir. You Gaia-hating climate destroyer. 🙂 (joking)
I get some odd looks when I tell people “It’s a solar panel for a sex machine”!!!
My hair started going many years ago someone asked my wife to be if she was bothered by my hair loss she said from where she was standing she couldn’t see the problem……she is 5ft 1/2inch and I’m 6ft 2inch tall.
James Bull
“With the inaccuracy of determining exactly when a pregnancy began in rural countries which lack pregnancy tests … low birth weight is the most reliable measure of whether a pregnancy has been negatively affected by an external factor.”
But low birth weight is obviously affected by the length of the pregnancy!
And I am sure birth weight is recorded accurately to the nearest tenth of a gram in all nineteen countries from which data was obtained.
I have no recent experience, but I think in the UK the weight quoted is now to the nearest five grams – but stand to be corrected.
When I was born, it was at 7 pounds 12 ounces.
Auto
I find that “climate change” is increasingly being conflated with weather events, and general environmental issues such as atmospheric pollution these days.
I think anyone making a claim about “climate change”, should first of all be asked what they mean by the term, because I think they often don’t know what they mean.
When the climate STOPS changing , THEN I’ll start worrying !!!!
Yes, I forgot to include “natural climate variation”, which is often conflated with man made climate change.
That’s the whole idea.
Agreed. But I think that confusing these two together is their intentional strategy at this point. And I doubt that they have any illusions or moral qualms about it being inaccurate, dishonest, and meant to deceive.
Here are the Warmists at work. First we were told that the weather is not the same as climate.
First the weather is not climate.
————————
WEATHER IS THE CLIMATE afterall! What a joke!
In case anyone wants to tell me ‘Oh, but its CLIMATE CHANGE’, I say so what? Climate change is well recognized and doesn’t tell me what co2 had to do with it.
+10
The article is total balderdash.
Climate takes 30 years to recognize any change.
Human gestation period is nine months.
How could climate have any effect whatsoever on birth weight ?
g
Do Eskimos have giant babies then?
ROTFLMAO !!!!
My son has finally reached climate age. There’s not a shred of truth in the suggestion that his birth weight was low, or in any other way abnormal. Quite mainstream in fact; couldn’t have been any more ordinary.
g
No but walruses have an oosik.
Every time I read headlines like this I think, “Why are they [the alarmists] still trying to change the public about Climate Change? Why are they still trying to sway opinion in favor of CAGW when poll after poll has shown that a) people generally don’t believe it, and b) nobody really cares?”
But today a new thought occurred to me, probably one that’s already occurred to others here: maybe these “pronouncements” about all the supposed negative effects of CAGW are *not* aimed at changing anyone’s mind at all, but simply for the sole purpose of creating “expert evidence” the EPA or the WHO will cite at some point in the future as the authority behind some Endangerment Finding they will use to bulldoze some anti-democratic central planning policy down our throats?
Because the alarmists spend SO much time and effort putting out this blather despite no one listening. Maybe it’s not for us at all, but for tomorrow’s totalitarian eco-regimes…
Look deeper, and you’ll find it’s the EPA and other usual suspects funding these studies, with the secret intent of using them later to build up an impressive-looking list of citations.
Yep, rogerknights, I think you’re right.
“To generate precipitation records for each birth, the team calculated the average precipitation for a given month within 10 km of the child’s birth location. This was done for each month up to one year prior to each child’s birth. The values were then summed over each trimester.”
so … missed the entire pregnancy!!
“authors are Frank Davenport, Heidi Hanson, Christopher Funk and Shraddhanand Shukla …”
notice the author?? timely
That says it all.
See NSF conflict of interest policy–section 510
http://www.nsf.gov/pubs/manuals/gpm05_131/gpm5.jsp
How common is the family name ‘Shukla’?
May it be coincidence?
I do not claim it IS coincidence.
Auto
I see the glitch there BC.
I’m quite certain that none of my kids was born within 10 km of where we were living during their entire gestation, and for the entire previous year.
So the location of their birth was in no way related to their pre-history.
Another classic case of a completely unrelated proxy assumption.
My oldest child in fact spent a very significant part of her gestation, travelling at least a quarter of the way around the earth; and a lot of that was actually sloshing around on the ocean, and included getting hit by a 640 KPH tsunami wave during the voyage. Perfectly ordinary outcome. I’m sure there were ozone holes and other TSI related perturbations for the duration. No idea what the DJI or the AMEX were doing over those periods either.
g
Well BC, your extract from their paper is clear validation of what I have said for many a year.
Statistical mathematics is an exact discipline, with no uncertainties in it; because the algorithms are always applied to a finite data set of all ready known exact real numbers; and those algorithms always work for any such finite data set, regardless of the presence, or absence of ANY relationship of ANY kind between ANY elements of the set.
So these ‘ birthers ‘ have certainly concocted a real bobby dazzler of a proxy for climate research.
g
What causes low birth weight is more likely the fact that these women are deprived of the affluence which industrialization would bring, and the education which would reduce the birth rate.
Dawg, you mean like the man and small boy having to hand crank the water pump in the picture? How much sooner would those pregnant ladies be able to get back in the shade if there was an electric pump, like in most civilized lacations?
1 gram = 0.0352739619 ounces = they are eking out 0.9 g in there data. How close is birth weight measured on a fidgeting baby? Most of our records are to whole ounces.
My mother wanted to name me HELL as 1936 was record heatwave! 1936 followed a record cold wave in 1935. I now weigh 193lbs and shrinking daily due to, AGW/?
http://www.c3headlines.com/bad-stuff-happens.html
Why do journals publish this rubbish. They don’t suggest that in this region of enquiry that the climate had indeed changed and they seem to assume that Global warming ie heating of the planet and climate change are interchangeable. I wonder if they had a control in the study to show if without the .02 a degree of warming in that region the babies would’ve been smaller.
I would think they’d find better correlation of birth weights to mom’s caloric intake than weather events…
Did it even occur to these charlatans that just maybe a lack of pre-natal clinics and pee-poor nutrition may play a major role here? Nah. Didn’t think so. Blame the weather. How or why are we still paying these clowns?
Less food, lower birth rate. The parameters would seem to coincide with that. Yet we put 40% of the US corn crop into our gas tanks in the name of climate change. It seems a simpler solution would simply be to put less food in gas tanks and more into the mouths of people in developing countries. Instead we drive grain prices higher with biofuel policies so food aid gets stretched too thin.
I am wary of being too overtly rude about the motives of those Agenda 21 types ultimately behind the Watermelon Scam that has harmed food availability worldwide.
But – I thought that that was the whole idea – do away with the non-elite.
I will end there, for fear of going seriously OTT.
Auto
seriously – we are talking about tenths of a gram? correlated to x days of temperature and some threshold of precipitation. this is a huge “so what, big deal” issue
0.5 grams out of a defined low birth weight baby of 2500 grams is 0.0002% difference. I fail to see any problem here at all
Most likely the difference is in the number of flies on the baby at the time of weighing it.
Climate Science Math.
Actually it’s a massive 0.02% – a scary 100 times worse than you thought
Randy,
My maths makes one gram in five thousand 0.0002, or 0.02%.
Auto
I should add – still negligible.
And, as noted, the babe is wriggling.
Auto
Why not suggest it cold be as large as 0.02% also, so unknown by a factor of 100:1
g
So I didn’t know that a natal scale was one of the priorities for AID workers when they trained mid-wives in Africa or that they took the time to train those people to be sure and gather a weight within a half a gram as one of the many important issues confronting a new born in impoverished areas there. Call me a cynic but I suspect these guys are mining a field of data that is largely made up of dodo!
It seems they could easily have had the headline that “Climate Change Positively Affects Birth Weight.” since birth weight was positively associated with increased precipitation. But then it doesn’t help that models create the wrong expectation by under representing the observed increase in precipitation. Recall the Wentz article in Science:
“There is a pronounced difference between the precipitation time series from the climate models and that from the satellite observations. The amplitude of the interannual variability, the response to the El Ninos, and the decadal trends are all smaller by a factor of 2 to 3 in the climatemodel results, as compared with the observations.”
http://www.sciencemag.org/content/317/5835/233
Wentz’s 2007 result was more recently independently confirmed with salinity data, showing that the models were under representing the freshening of the oceans due to continental runoff. I wonder if it is still a factor of two or three?
“This rate is double the response projected by current-generation climate models and suggests that a substantial (16 to 24%) intensification of the global water cycle will occur in a future 2° to 3° warmer world.”
http://www.sciencemag.org/content/336/6080/455.abstract
More good climate news for a thirsty world!
In the 1970’s I was a Peace Corps Vol. in Brazil. Among other things, I organized a pregnancy and infant supplemental feeding program. My anecdotal experience is that birth rate varies with caloric intake of the mother, ceteris paribus.
David
Wife and I live in Central Texas. So hot and dry are a given. Why did our two daughters weigh 9 lbs 9 oz and 9 lbs 2 oz when born?
I bet you think that it was because your wive had good nutrition but that is only because you are a reality avoiding right wing bible thumping evolution denying enemy of the PEOPLE! /snarc
Cause your wife wasn’t, and neither was her food supply. These African
ladies have no AC. They have no food refrigeration. And food staple yield is directly correlated with adequate rain. And indirectly correlated with heat, in the absence of rain. Wrote about this extensively in Gaia’s Limits and Arts of Truth, using Kenya’s national dish ugali as the entry point to the issue.
So you’re saying that a high standard of living and an energy dense economy would make it better for their children?
Everything’s big in Texas?
All that Texas long horn beef your Wife was putting away. Seems like the results were great.
g
I say Follow the money! Who funded this study then?
Cheers
Roger
http://www.rogerfromnewzealand.wordpress.com
Explain the Massai – always hot and always low precipitation.
Why do they associate hotter and dryer weather with climate change? They tell us that extreme cold and wetter weather events are also caused by climate change. So maybe it was the case that the hotter and dryer times were normal weather events, and the cooler and wetter times were caused by climate change. How would they know which is which?
correction – Maasai
Yes, and there are other tribes who are equally tall or even FAT such as some of the natives in various hot equatorial islands in the Pacific. They are huge!
“Services such as education, clean water efforts and nutrition support won’t be as effective. We need to work faster and differently to combat the evident stresses caused by climate change.”
Work faster and differently to do what? What could we do that would be more effective than providing education, clean water, and nutrition? Stop them from using fossil fuels?
Are these people trying to gain notoriety as the most stupid claim on WarmList?
and birth weight in 19 African countries.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Oh for crying out loud……low birth weight is common in babies born to parents who are of black African origin!!!!!
..it’s fin genetic
Who is the l y i n g c r o o k that did this study?
Getting back to my Volunteer EMT training, on a hot day everyone weighs less, it’s called dehydration. It impacts pregnant women, who are under no small amount of stress, and their soon to be born or recently born child. It’s the one reason we carry so much water and a few extra bags of ice on the Rescue/Transport Vehicles that we support the NPS with in Sleeping Bear Dunes. The Dunes highest rate of rescues of any national park, primarily due to, you guessed it, dehydration, (often brought on by stupidity).
Another Shukla!?
70,000 births in 19 countries and they correlated each one with precipitation and temperature?
Oh wait, they used a large scale homogenization process. That must make it a rotten mess considering most of those places do not efficiently track temperature or precipitation.
Not forgetting the episodic and very transient nature of thunderstorms.
Nor did they bother to perform a similar miracle during pre-AGW years. Why bother, after all, they decided the outcome and then wrote the paper to meet it. No control data sets needed.
So, having done a study over 24 years on perhaps 0.001% of the African population at best they come to the conclusion that climate change is to blame.
Pure genius.
The study is a little strange, but I guess any excuse to tie climate change with any bad to secure funding is par for the course these days. However, it is believed that climate change drove “Lucy” from trees to walk upright in grasses.
Finally, an unequivocal definition of “climate change.”
Now it must be determined which areas of the globe are experiencing these climatic symptoms, and all pregnant women must be moved elsewhere. “Social justice” implies the right of every woman to birth big babies, however unsustainable that might prove to be.
Post hoc ergo PROCTOLOGIST HOCKEY.
I’m confused. The headline says Climate Change (TM) “affects birth weight” but the story says “the potential to significantly impact birth outcomes.” So does it impact birth weight (very scary) or merely affect birth weight.
Inquiring minds want to know.
And how does the alleged effect/impact compare with the effect of giving the mother a few decent meals?
“Climate” is just information about weather that has been aggregated for a given time period and geographical space, and which has been simplified into averages, trends, and myriad other simplifying concepts in order to make it possible for human beings to hold in our brains, and to meaningfully compare and talk about.
If our brains and our means of communicating with each other were sufficiently complex and quick, and suitably optimized for the task, and if we had enough time, we would be able to talk in terms of all the actual weather that happened in the relevant geographical space over the time period in question, and we would not need the simplifying/aggregating concept of “Climate” to help us do this. We would be able to just discuss and compare the actual weather that had happened throughout the time in question in the relevant geographical area of interest.
To put the point another way, “Climate” is not something that actually exists in the world. It only exists in our simplified conceptualization of the world. You cannot actually go out and experience and measure “climate”, as opposed to weather. You can only experience and measure the weather. It would not make any sense to say, for example, “that rain today is “climate” whereas yesterday’s rain was weather”. There is only weather. There are no observable features in the world which are “climate” but not weather.
We only talk in terms of the “Climate” because we have finite time, and limited mental processing and communication capacity that requires us to aggregate and simplify when we want to describe and compare weather over a period of time and/or in a geographical space.
Climate is an entirely human psychological construct that just makes our lives easier when it comes to conceptualizing the weather that has taken place over time and space.
Climate does not actually exist in the world. Only weather actually exists in the world.
This is part of the problem sometimes when people talk about climate change. The thing that they think they want to say is changing does not actually exist. Gosh, someone should have checked…
Hope this helps.
Congratulations they have discovered that dehydration and malnutrition are bad for pregnant women.
The thing that hasn’t occurred to them is that Africa was not cool and wet before we started burning coal and oil.
Meanwhile back in the real world the WHO shows where the problem REALLY lies
“This chapter seeks to explain why progress in maternal and child health has apparently
stumbled so badly in many countries. Slow progress, stagnation and reversal
are clearly related to poverty, to humanitarian crises, and, particularly in sub-Saharan
Africa, to the direct and indirect effects of HIV/AIDS. These operate, at least in part,
by fuelling or maintaining exclusion from care. In many countries numerous women
and children are excluded from even the most basic health care benefits: those that
are important for mere survival.”
Sick people have sick babies.
Keith
“Keith Willshaw
Sick people have sick babies.
Keith”
Healthy mothers can have sick babies. As well as unhealthy mothers can have healthy babies too. So climate has no bearing on the outcome.
Hmmnn…
Hot and dry conditions [effectively a drought] affect the birth weights of babies in [I presume] subsistence farming communities in Africa. Now there’s a surprise.
So what effect do warmer conditions have on babies’ birth weights in Siberia, northern Canada and Lapland?
So I suppose Florida babies must be smaller than Maine babies? This should be easy to check, if anybody cares.
Regardless, the issue is of no interest in the Lower 48 because our average temperature has cycled up and down a bit for the past 100+ years but the overall average has not changed.
“So what effect do warmer conditions have on babies’ birth weights…?”
According this paper linked below: Lifespan depends on month of birth
Seasonal differences in nutrition and disease environment early in life could explain the relationship between month of birth and adult lifespan. In past decades, the food supplies in general, and the availability of fresh fruit and vegetables in particular, differed from season to season. Mothers who gave birth in autumn and early winter had access to plentiful food and fresh fruit and vegetables throughout most of their pregnancy; those who gave birth in spring and early summer experienced longer periods of inadequate nutrition.
http://www.pnas.org/content/98/5/2934.full
The Univ. of Utah study referenced in the top post looked at 19 African countries. Without knowing which 19 were examined, it’s impossible to know any or all the plausible variables such as seasonal variations in food supply, type of nutriiton available, rainfall, and what have you, that would make some assessment of this work viable. Until you can account for all the variables, you haven’t got jack.
Patrick
October 1, 2015 at 5:38 am
‘Healthy mothers can have sick babies. As well as unhealthy mothers can have healthy babies too. So climate has no bearing on the outcome.”
No, I think you’re off-course here. Climate and/or weather can affect many things. It’s foolish to get into disputes arguing this point; it is a losing effort, and a lost cause.
Climate changes. Of course it does. Climate and/or weather can affect crops, harvests, and mortality. See the NAS study I linked for more on infant births.
The dispute is not about climate change, it’s about Catastrophic Anthropogenic Climate Change, CAGW where man’s CO₂ is the demon trace gas, the molecule that roared, and stoked the flames of a thermageddon even now melting cities near you, and making poley bears, pant, rant, and even seek a grant.
In my view, climate and/or weather affect everything. That fact makes it easy for the alarmists to trot out all manner of weak associations they’ve found, and claim that it’s due to climate change. That’s all fine and well, but what skeptics are asking for is proof that man’s CO₂ has anything at all to do with it, and anything to do with CAGW, AGW, global warming, climate change, climate….whatever you want to call it.
Further reading on relationship between seasonal fluctuations in birth weight, and the role of birth weight in later health outcomes. The health of the mother plays a critical role in the overall health prospects for her newborn.
Seasonal Fluctuations in Birth Weight and Neonatal Limb Length;
Does Prenatal Vitamin D Influence Neonatal Size and Shape?
Conclusion:
Environmental factors that have regular seasonal fluctuation influence both the size and shape of neonates. Animal experiments suggest that prenatal hypovitaminosis D may underlie greater limb length. Because birth weight and limb length are associated with a broad range of important health outcomes, the seasonal exposures underlying these effects warrant further scrutiny from a public health perspective.
1. Introduction Birth weight has long been acknowledged as an important measure of neonatal health
In addition to providing insights into prenatal development, this variable is known to be associated with a wide range of important cognitive, behavioural and health outcomes in infancy, childhood and adulthood. For example, even within the normal range of birth weights, heavier birth weight has been associated with uperior neurocognitive outcomes in several cohort studies
There is accumulating evidence linking birth weight and wide range of chronic, adult-onset disorders
http://dash.harvard.edu/bitstream/handle/1/3743677/sdarticle-3.pdf?sequence=1
I should have said:
“The health of the mother during pregnancy plays a critical role in the overall health prospects for her newborn.”
In editing the pdf of the Harvard study, I goofed:
“has been associated with s</buperior neurocognitive outcomes in.."
If at first you do goof up, you may goof, and goof again:
s/b “…heavier birth weight has been associated with superior neurocognitive outcomes..”
“In fact, just one extra day with a temperature above 100 F in the second trimester corresponded to a 0.9 g weight decrease; this result held with a larger effect when the temperature threshold was increased to 105 F.”
Water or lack thereof is the common denominator. The availability of water to the pregnant women and how much she drinks water seems most important. Rainfall suggests the availability of water, and temperature above 100F suggests the willingness to drink water is reduced; i.e., feeling sluggish.
With limited rainfall there are less crops; hence, less food. Is the rainfall and birthweight information a surrogate for maternal nutrition? I think so. Marginally nourished mothers can readily tipped over into being malnourished which has some effect on birthweight. Parity, that is, the number of pregnancies the mother has had also impacts subsequent birthweight with maternal nutritional status declining with subsequent pregnancies, especially when the mother is already marginally nourished.
I am surprised that there were only 70,000 pregnancies available for analysis in a continent so vast with a billion or so people in a span of 24 years. There was a lot of selection of the population and location.
As I understand the climate change hypothesis, temperatures in the tropics will not be effected, rather, both poles will reflect increasing global temperatures. I am not sure why climate is being implicated except as the authors saying things that will please the funding agencies associated with Government although the money will flow through the hands of NGOs.
Just a few questions that I am mulling in my head.
From an earlier version of this study at http://paa2014.princeton.edu/papers/141512:
Using a variety of assumptions, the authors got the result they were looking for as regards affects of weather on birth weight. Future warming and drying (AKA “climate change”) is pure speculation.
As a researcher in perinatology (high risk pregnancy), I find this study rather problematic in its methods and conclusions. As written, the study doesn’t seem to control for significant confounding variables.
This study seems to make the bold assumption that the only thing that has changed in 24 years is temperature. I find that very unlikely.
Population growth affects availability of resources. Land use changes have very significant impact on rainfall, crop yields, local temperatures, etc… Social and economic stressors can have a dramatic effect on birth weight. Decreased access to health care can certainly have a negative impact. Changes in political priorities can affect the availability of resources or quality of environment. I could go on.
The study does not demonstrate temperature or precipitation trends. Table 1 in the early version shows that the DHS birth record surveys used by the authors were taken at most 4 times in any of the 21 nations during a span of 19 years.
True, the authors don’t demonstrate temperature or precipitation trends. However, they are testing bivariate relationships (birthweight and temperature), which implies a trend if one takes the author’s heading of “Evidence and impact of climate change” seriously. I don’t.
I wouldn’t bother to look at the SI materials as it is clear that the invocation of “climate change” is for funding purposes and lends nothing of value to their conclusions.
Maybe I didn’t look hard enough but I couldn’t find what journal this study was published in.
Published in Global Environmental Change:
http://www.journals.elsevier.com/global-environmental-change
Which is to say it probably would not have been published without the “Climate Change” attribution.
The NIH has a somewhat contrary conclusion regarding climate change and pregnancy outcomes:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4468458/
Apparently, previous studies didn’t have media appeal.
Thanks for the reference, verdviewer.
Seriously… Global Environmental Change? I checked their ranking among journals based on their productivity and citation impact (H Rank). GEC ranks a whopping 1,235th place. I wouldn’t publish in a journal of that low ranking. Anyway, that explains how the paper got published when it is such weak soup.
I think I’ll trust NIH as they base their conclusions on a broad base of current published literature.