Peer reviewed whack a mozzie

Via the SPPI BlogTrying to Hit a Mosquito with a Sledgehammer

Source:  World Climate Report

One of the standard tenets of the global warming bible is that malaria will get worse as temperatures rise. We’ve addressed this many times before, primarily by noting that the link between high temperatures and high malaria infection rates is anything but straightforward. Infectious disease expert Paul Reiter is quick to point out that malaria has been observed inside the Arctic Circle…and this is obviously not typical of a so-called “tropical” disease.

Nevertheless, the case for a malaria-temperature relationship stands on reasonably solid ground. Mosquitoes are more active at higher temperatures so they can expand their range. Biting frequency also depends on temperature, to some extent, so this should increase the infection rate, assuming the little buggers can find enough people to bite. Fairly sophisticated models have been developed that estimate the impact of weather variables on malaria infection rates. On the face of it, this seems like a reasonably solid argument.

But in a recent paper in Nature, Oxford University’s Peter Gething and colleagues from Oxford and the University of Florida took a careful look at global malaria data to see if the predicted trend was correct.

They uncovered data from around the year 1900 showing where malaria was observed. These data not only show where malaria occurred, but also different categories of endemicity (in locations where the disease is continually present, the categories depict the approximate percentage of mosquitoes that carry the malaria parasite). 1900 is a key time because of the lack of prior malaria intervention efforts. The authors then used a current model of the parasite’s transmission to create a map at the same scale for the year 2007. The 1900 and 2007 maps are shown in Figure 1a and 1b, respectively. It’s then a simple matter to subtract the two maps to show how malaria endemicity has changed over the last 100 plus years (in this case, this is a subtraction of categories). This is shown in the bottom Figure (1c), where red shows increasing malaria and blue decreasing malaria.

There is virtually no red on the map.

Figure 1. Malaria endemicity in 1900 (a, top) and 2007 (b, middle) by increasing severity category. The difference in endemicity (c, bottom) from 1900 to 2007 indicates worsening malaria in red areas and improvements in blue (Gething et al., 2010).

If you give this issue a moment of thought, this result should be obvious. Of course malaria is not as bad now as it was 100 years ago. Global health interventions should have reduced the problem significantly.

But it has also been warming since 1900, including nearly all of the regions were malaria was endemic. Look at the problem this way: if you had available to you a) the current malaria/climate models, b) the 1900 malaria map, and c) a fairly accurate prediction of future temperatures, there is no possible way you would have predicted anything close to the map shown in Figure 1b for 2007. That’s because the climate models do not consider factors other than climate (this is also why heat-related mortality/climate model projections don’t work either).

It’s fair to say that everyone who works on this issue is pleased that malaria is less of a problem now. This speaks to the importance of intervention and awareness programs in fighting transmission. And the trend really shouldn’t be that surprising. But one might argue that regardless of the Gething et al. result, this does not mean that climate is not important.

The key part of the Nature paper, however, is the author’s attempt to quantify the effect of climate compared to other factors. To estimate these, they calculated something called the “basic reproductive number” of the malaria parasite (this is a measure of how efficiently the disease spreads within a population that has no inherent resistance to it). Even though the exact reproductive number is hard to predict, you can estimate the magnitude of the changes (also called the “effect size”) that might arise from different factors, such as climate or intervention programs.

Climate projections vary, of course, depending on the models and assumptions used, but the maximum effect sizes for the year 2050 arising from climate changes are around 2 or 3 (a doubling or trebling of the reproductive number). By comparison, the observed changes in effect size (between 1900 and 2007) were much greater than the projected climate change impact. More specifically, Gething et al.

…found that, of the 66 million km2 of the Earth’s surface thought to have sustained stable/endemic malaria in 1900, 12%, 18% and 57% had exhibited proportional decreases in the reproductive number of up to one, between one and two, and greater than two orders of magnitude, respectively; 11% had shown no evidence of change; and 2% had shown evidence of an increase in the reproductive number by 2007. Although imperfect, this simple comparison illustrates that despite warming global temperatures, the combined natural and anthropogenic forces acting on the disease throughout the twentieth century have resulted in the great majority of locations undergoing a net reduction in transmission between one and three orders of magnitude [emphasis added, Eds.] larger than the maximum future increases proposed under temperature-based climate change scenarios…When compared to the substantially smaller proposed magnitude of climate-induced effects, an important and simple inference is that [climate change impacts] can be offset by moderate increases in coverage levels of currently available interventions.

In other words, if we are really interested in stopping the spread of malaria, there are more effective ways of dealing with it than undertaking draconian global legislative efforts to reduce greenhouse gas levels—the equivalent of pummeling a mosquito with a sledgehammer.

Reference:

Gething, P.W., Smith, D.L., Patil, A.P., Tatem, A.J., Snow, R.W. and S.I. Hay, 2010. Climate Change and the Global Malaria Recession. Nature, 465, 342-346.

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Ale Gorney
June 16, 2010 10:25 pm

Malaria is on the rise in South Africa… turn your TV on during one of the world cup matches and you can hear the buzzing of the mosquitos. I’m surprised the entire nation hasn’t been killed yet.

Evan Jones
Editor
June 16, 2010 10:32 pm

The beastly Sovs — as objectionable as they were — sure didn’t shilly-shally around when it came to wiping out malaria.

James Sexton
June 16, 2010 10:35 pm

All one has to do is read the history of the Panama Canal to see how scary malaria would be today. About every other year, we have a mosquito borne disease that we’re supposed to be incredibly frightened of. To me, it is maddening. If we were really concerned about the diseases mosquitoes carried, we’d have the disease killed in a few days. We’re not. It is simply a scare tactic for the mind numbed youngsters today. They, apparently, don’t teach history anymore.
Peace.

Nick
June 16, 2010 11:00 pm

Actually, one of the “standard tenets of the global warming bible” is that mosquito-borne diseases will benefit from a warming world -not malaria alone.
And why the rhetoric of the last paragraph? “Draconian” legislative efforts on AGW are not aimed solely or primarily at disease control. Has anyone seriously argued that addressing AGW is the best or the only way to stop the spread of malaria,or other disease? Has anyone credible argued that we’re not “interested in stopping the spread of malaria”? How would anyone deal with climate modulated disease except through manipulating coverage levels of currently available interventions?

Martin Brumby
June 16, 2010 11:04 pm

says: June 16, 2010 at 10:32 pm
“The beastly Sovs — as objectionable as they were — sure didn’t shilly-shally around when it came to wiping out malaria.”
But our nice friendly greenie chums, led by Rachel Carson’s pseudo science, condemned millions to die with their DDT ban.

tty
June 16, 2010 11:36 pm

Actually the argument that mosquitoes become more active when it is warmer is a weak one, because malaria infection most commonly takes place at night and indoors. So infection is very much a matter of bad housing, and also explains why Mosquito nets and/or occasional spraying of huts with DDT is fairly effective in preventing the disease.
In Finland for example the last malaria outbreak of consequence occurred during the Winter War 1939-40. This was a winter of epic proportions with long periods with temperatures below -40, but of course there was a lot of refugees, with many people sleeping in crowded conditions and in substandard housing, not normally used.
As late as the 1930’s malaria was endemic in much of Siberia, including Yakutia which has the coldest winters in the northern hemisphere.

Jimbo
June 16, 2010 11:51 pm

That’s because the climate models do not consider factors other than climate (this is also why heat-related mortality/climate model projections don’t work either).

—-
This is also why dire predictions about mass deaths by the year 2000 (made in the 1960s and 1970s) due to starvation as a result of the population explosion has not materialised. The only factors they saw was then current agricultural production and the rise in population without looking as potential increases in food productivity which actually occured. IMHO the same argument now applies for ‘rising’ sea levels and climate refugess.

pat
June 16, 2010 11:59 pm

Mosquitoes are seasonal. They have an extremely short life span. They seem to be extraordinarily feisty in the tundra. Where they attack with gusto. Nevertheless, assuming the hypothesis is true. Since the range of malaria has decreased markedly, while temperatures are approaching a death spiral according to Warmists, I think we must all question the relationship between malarial contagion and temperature. And consider the fact that numerous areas of historical infection were ameliorated by way of insecticide. That would be the Northern Hemisphere.
Hey.
Why let reality intrude on another myth created by “scientists” well outside their field, but well inside the money generated by hysteria and increased taxes.

jon
June 17, 2010 12:05 am

The Soviets reduced the incidence of malaria by killing tens of millions of the host organism, i.e. humans. The AGW crowd wishes to repeat that success by making food less available.

June 17, 2010 1:45 am

There are some fabulous quotes on this story on the BBC:
http://news.bbc.co.uk/1/hi/science_and_environment/10127989.stm
Dr Gething. (on malaria)
“Climate change is, in our view, an unwelcome distraction from the main issues.”
Dr Gething
“A lot of the studies proposing there would be a dramatic increase in a warmer world have been met with guarded criticism, and often what’s been said about them surpasses what the actual science indicates.
“So this redresses the balance a bit.”
Chris Drakeley, director of the Malaria Centre at the London School of Hygiene and Tropcial Medicine, suggested the group’s conclusions were broadly correct.
“I am slightly sceptical of the furore surrounding (malaria and) climate change in the sense that we have to bear in mind there are other factors that are moving much faster than climate change,” he said.
“I don’t doubt climate change is happening, but we have also seen an increase in the coverage of treatment, and in the last 20 years there has been a huge amount of information and education on malaria made available in Africa; and that’s all changed much faster than the climate.”
———————–
Did you know about the Michael ‘hockey stick’ Mann climate change and malaria connection?
http://www.examiner.com/x-9111-Environmental-Policy-Examiner~y2010m5d21-Global-warming-Michael-Mann-finds-a-new-research-plaything
“But Matthew Thomas thinks differently. Matthew Thomas said that the study “plays down the potential importance of climate [change]”.
Who is Matthew Thomas? He is a researcher at… Penn State. Matthew Thomas is a researcher… at Penn State… who has just won a $1.8 million grant to study the influence of environmental temperature on transmission of vector-borne diseases. Think he has a dog in this hunt?
Ask his co-investigator on the project. Michael Mann…”
followed up here:
Global warming: Malaria and Joe Romm’s logic fail–and downright dishonesty
http://www.examiner.com/x-9111-Environmental-Policy-Examiner~y2010m5d24-Global-warming-Malaria-and-Joe-Romms-logic-fail
“After an article here was published about Michael Mann’s participation in a research study on the spread of malaria and climate change, it was only a matter of time before Joe Romm, the defender of hysteria in all matters climatological, would weigh in on the subject.”

My2Cents
June 17, 2010 1:47 am

It would be an interesting exercise to compare the reduction in malaria infections to the reduction in swamp lands that are needed by the mosquito to breed. This could explain many of the areas where large decreases have occurred.

June 17, 2010 1:47 am

Found in the comments section at Bishop Hill:
http://bishophill.squarespace.com/blog/2010/5/19/the-idea-of-oxburgh.html?currentPage=3#comments
“I see the malaria study by Peter Gething in Nature has caused quite a stir.
http://www.nature.com/nature/journal/v465/n7296/abs/nature09098.html
In particular, it has upset Matthew Thomas, researcher at Pennsylvania State University.
http://www.guardian.co.uk/environment/2010/may/21/climate-change-insects
You may ask who is Matthew Thomas?
Well he is Professor of Entomology, at Penn State’s Center for Infectious Disease Dynamics, who explores explores the ecology and evolution of “enemy-victim” interactions (malaria).
In 2009 he published a paper; Paaijmans, KP, Read, AF & Thomas, MB (2009). Understanding the link between malaria risk and climate. Proceedings of the National Academy of Sciences 106:13844-13849.
The Nature study by Peter Gething clearly debunks any serious link between malaria risk and climate. No wonder Matthew Thomas is angry. Gething has attacked his academic credentials, he could put Thomas out of the climate change business.
Now you may argue that is not really important.
Well it is really important to Thomas, Penn State and others. For you see Thomas was awarded a very large grant last year; “2009-2013 Quantifying the influence of environmental temperature on transmission of vector-borne diseases, NSF-EF [Principal Investigator: M. Thomas; Co-Investigators: R.G. Crane, M.E. Mann, A. Read, T. Scott (Penn State Univ.)] $1,884,991″
$1,884,991 is a lot of money to be investigating the influence of environmental temperature on malaria when such influence has now been shown to be of little consequence. It is interesting to note that you could buy a lot medicine and nets with $1.8 million.
More intriguingly is the name of one of the co-investigators – M.E. Mann.
Now that couldn’t be Michael E Mann of Hockey Stick fame, could it? Oh yes it is!
Now you see why it is so important for Penn State to discredit Gething’s study.
Mann provides the temperatures, Thomas provides the link with malaria and Penn pockets the money.

e_por
June 17, 2010 2:14 am

The reason for more bites of mosquitoes in warmer places has nothing to do with heat affecting the mosquitoes, rather the heat effect on people:
When it is hot, people wear less clothing, especially at night (even the modest people wear less at home). That way the mosquito have better access to human flesh.
Elementary.

Roy
June 17, 2010 2:40 am

@ James Sexton:
“All one has to do is read the history of the Panama Canal to see how scary malaria would be today.”
Yes, the problems in Panama that defeated the French attempt to repeat their success with the Suez Canal are a good example. Another, more recent example of the problems caused by malaria is the experience of the British/Indian 14th Army that drove the Japanese out of Burma in World War II. At one stage the malaria rates in the 14th Army were quite horrifying, but by means of strict disciplinary action General Bill Slim was able to achieve a drastic reduction in cases, as described in the paragraph copied below from the Wikipedia article about him.
http://en.wikipedia.org/wiki/William_Slim,_1st_Viscount_Slim
“He was also concerned with the health of his troops and the impact of this on their fighting efficiency. In his book “Defeat into Victory” he tells of the malaria rates among his units being 70%, largely due to noncompliance by his soldiers with the foul-tasting quinine medication they refused to take. Slim did not blame his medics for this problem, but placed the responsibility on his officers. “Good doctors are no use without good discipline. More than half the battle against disease is fought not by the doctors, but by the regimental officers.”[47] After Slim dismissed a few officers for high unit malaria rates, the others realized he was serious and malaria treatment was enforced, dropping the rate to less than 5%. The combat effectiveness of his army was thus greatly enhanced.”

kadaka (KD Knoebel)
June 17, 2010 3:23 am

What I remember is we used to be plagued with mosquitoes here in central Pennsylvania. To go outside during the late spring to early fall we’d have to resort to numerous bug repellents, assorted sprays and the like, and still we’d end up devoured half the time.
It’s been quite a while now since they’ve been a problem. No repellents, it’s the same great outdoors outside, there might be a few bad days a year but “bad days” used to be the norm. We’ve been getting some massive mayfly swarms, here near the river, mini-marts and other places turn off most of their outdoor lights at night to avoid drawing them in. Really, it can be dangerous to inhale with your mouth open. We are told such swarms are a good thing, sign of good water quality, so I guess the water is good for the mosquitoes as well. Yet every fall at the clearance racks in the stores, many citronella candles and assorted mosquito repellents.
Long stretches of cold wet weather, so many cloudy days versus so few clear ones that depending on solar power is impractical to impossible, and now the mosquitoes seem to have gone away… It’s like something statistically significant happened over the last 15 years… 🙂

Gary Pearse
June 17, 2010 3:23 am

Nick:
I wonder… Do you think pretty much of the rest of the projected devastating effects of global warming might be offset by remedial interventions? One could build dykes to hold back the sea,.. One could…naw this probably isn’t even doable. Greenpea and the rest of the agw cheering section would intervene to stop this.

MACK1
June 17, 2010 3:55 am

“(this is also why heat-related mortality/climate model projections don’t work either)”
If you need a laugh, have a look at McMichael et al on this topic
http://ije.oxfordjournals.org/cgi/content/abstract/37/5/1121
“Estimates of the temperature threshold below which cold-related mortality began to increase ranged from 15°C to 29°C; the threshold for heat-related deaths ranged from 16°C to 31°C.”
Then of course “Additional research is needed….”
How can they keep a straight face? And why on earth should they get any more money when there is plenty of serious research to be done?

June 17, 2010 4:17 am

Rotary International has run a huge programme over a number of years aimed at eradicating Malaria from all parts of the workd they have access to. Their programme is funded entirely by RI and its members and dispenses nets, DDT, and educates the recipients about how to soak nets in DDT, and also how to eradicate the disease-carrying mosquitos. A huge amount achieved without fanfare, to the point where ‘scientists’ and environmental advocacy groups seem unaware of this major reason for Malaria disappearing from many poorer nations. Malaria incidence will rise again when populations become impoverished and contact with agencies such as Rotary International are lost, as has occurred in parts of Africa and in other parts of the world where greedy and ignorant rulers have encriched themselves and their cohorts while their various peoples have descended into extreme poverty.
Any rise in the incidence of Malaria and other insect-borne diseases are a direct result of poverty, not a slight rise in temperatures since the beginning of the industrial revolution. Greedy despots in the undeveloped world are encouraged by the CAGW alarmists in the West to pay these ignorant/cynical governments huge reparations. Sadly, many of the West’s current political leaders see no cause to even question those ridiculous demands for ‘reparations’.

Geoff Sherrington
June 17, 2010 4:19 am

Please don’t overlook that there are various forms of malaria, with different resistance to treatment.

Without rapid treatment, P. falciparum malaria can cause life-threatening complications. Of those receiving treatment, about 15 to 20 percent will die. For nearly all people who do not receive proper treatment, the infection is fatal.
Read more: Falciparum Malaria Symptoms | eHow.com http://www.ehow.com/about_5082730_falciparum-malaria-symptoms.html#ixzz0r6m9OBIQ

Kevin B
June 17, 2010 4:20 am

My2Cents says:
June 17, 2010 at 1:47 am
It would be an interesting exercise to compare the reduction in malaria infections to the reduction in swamp lands that are needed by the mosquito to breed. This could explain many of the areas where large decreases have occurred.

Draining the swamps had a large impact on the range and severity of malaria, (aka ague), in Britain. Of course, now we don’t call them swamps, we call them wetlands and we are ‘restoring’ them at a great rate.
But if this results in an increase in malaria, AGW will be to blame, not the lovely wetlands.

Geoff Sherrington
June 17, 2010 4:21 am

Sorry – hit the wrong key.
I wished to add that the incentive to finally eradicate malaria is just as high as ever. Those who delay its eradication while they finish learned papers or complain about people getting injections are a modern equivalent of mass murderers.

BarryW
June 17, 2010 4:25 am

The problem is how do you control for the increase in public health actions that would decrease the prevalence of malarial infections?
The hypothesis is that warmer weather will cause more malaria cases to occur outside of the previous range. Global temps have increase since 1900. Therefore once should see red in the third map outside of the areas where infections were prevalent in 1900. But you don’t.
It used to be lies, dammed lies, and statistics. Now it’s lies, dammed lies, statistics, and models.

toby
June 17, 2010 4:42 am

I certainly agree with this posting … we should tackle malaria growth directly, and not via global warming-related legislation. Personally, I know of one area where malaria was previously banished but has returned. The same country has also seen a rise in viral illnesses like chickengunya.

Pascvaks
June 17, 2010 5:50 am

The Great State Bird of Alaska is NOT the problem, it is only the vector by which the problem is transmitted. In our present state of healthcare and “preventive control measures” life is frairly good for most, and seemingly getting better for many more. As civilizations wax and wane the incidience of disease in all categories goes up and down.
On the matter of throwing money at the problem, you get the biggest bang for the buck if “politics” is out of the equation. Don’t trust anything you really want to the care and management of a politician, or group thereof.

Enneagram
June 17, 2010 6:06 am

During the 1960´s Malaria and Dengue had been erradicated in most southamerica, however after the binding prohibition bill issued by the GLOBAL GOVERNANCE through its Health Secretary, the World Health Organization, both illnesses reappeared even where before were unknown, in big cities.
http://www.green-agenda.com/index.html
http://www.mitosyfraudes.org/Ingles/Killer.html

Jeff Cormack
June 17, 2010 6:07 am

Effective eradication programs are the only long term solution, and, we already have them. DDT used properly is most effective http://rachelwaswrong.org/malaria-legacy/ . Good roads. stable governments and literate populations all help in the delivery of disease relief. Until we do more in these areas no success will be achieved.

Olen
June 17, 2010 6:25 am

How cold do global warming people say the earth will have to be to wipe out malaria, colder than the arctic circle. Certainly colder than Finland I would think.

Paul
June 17, 2010 6:27 am

Or could one possibility simply be that the correlation between heat (or the lack thereof) and mosquitoes/malaria does exist and that it is the globalized temp records
over that time period that are wrong?
Also, a certain (significant?) amount of the retreat in malaria is due to habitat-loss for mosquitoes due to mostly human development (swamp draining, improved water management practices, etc.) that has implications for the local hydrological cycle and climate. In other words this info helps to corroborate the significant direct impact of human development on local temps, which go beyond simply the UHI.
May I also have a research grant, if you please? I promise I’ll only buy just one Porsche with it this time. That and my big oil money was coming from BP, and their last cheque bounced.

Robert M
June 17, 2010 6:51 am

Martin Brumby says: But our nice friendly greenie chums, led by Rachel Carson’s pseudo science, condemned millions to die with their DDT ban.
Martin,
The Problem with our greenie chums and libtards in general is that the only thing that matters to them is INTENT. By the time the disasterous results of their good intentions occur thay have already moved on to their next project. They cannot see that in a lot of cases, the current project is to try and fix what they broke with their last project.

Steve P
June 17, 2010 7:06 am

Birds and fish eat a lot of mosquitoes and their larvae.
Unfortunately, many swallow colonies – yep, even those famously returning to San Juan Capistrano – have been “relocated,” or simply destroyed, because some humans complained about bird droppings.
‘Same was true at Mission San Luis Obispo up the coast in Cal. – the swallows (and pigeons) were banished from the mission. Where once the sky over the mission was filled with Barn and Cliff Swallows, especially at dawn and dusk, now there are none, and the county sprays (selectively) for mosquitoes at the nearby, redundently named Lake Laguna.
A study has been done showing that Purple Martins couldn’t possibly be eating 2,000 mosquitos per day/bird based on the argument that the two species aren’t active during the same time frames.
Yes, all those Purple Martin houses were just there for the decoration.
My experience is that mosquitoes are active during the day in shady, damp areas shielded from the wind. It was one of the first lessons I learned as a youngster tromping through the woods.
Purple Martin numbers have decreased markedly, at least partialy because of competition with Starlings and English sparrows for nesting sites. Neither of these non-native, imported Eurasion species does much flycatching.
It is true that many mosquitoes hide and rest during the day on vegetation. There they are subject to predation from the many species of hunt and peck birds which scour the branches and leaves for just such resting insects. Wood warblers are a good example of birds using this hunting technique. Do they eat resting mosquitoes? I don’t know, but I would think it highly likely.
Once the balance of nature has been disturbed, man’s efforts to regain the upper hand may in fact make the situation worse. At least some species of birds have had their reproductive cycles affected by the application of DDT, and potential aquatic predators of mosquito larvae are also impacted by the pesticide.
No, Bald Eagles and Peregrine Falcons don’t eat mosquitoes, but they are birds, and both had their populations crash because of massive spraying with DDT, and that’s far from the only pesticide or herbicide being applied to the environment.
Eagles and Falcons are large, majestic, relatively easily observed species. Not so for wee mites like the American Redstart.
Finally, DDT has lost much of its former effectiveness due to over- application and resultant development of resistance in mosquitoes.

Pamela Gray
June 17, 2010 7:54 am

I second the observation that bugs have dropped outa sight. And so have my bats. No bugs, no bats. And with no bats, my great horned and barn owls will go away. Which means my yard will be infested with mice. Cold weather brings vermin into our living quarters, and we know what kinds of diseases those nasty little creatures carry. Trouble is, mice poison tastes good to dogs, and cheese traps snare sensitive noses. I’ve even tried live traps. Took two days to get my Jack Russell’s head out of it.
The solution? Get a cat. Perfect pest control solution. If you have a big dog, you probably want to get a big cat. However, I once had a runt cat with a crooked tail chase two German Shepherds off the property.

Lena Hulden
June 17, 2010 8:14 am

There were no malaria in Finland during the Winter war. The frontier was mobile and people slept in temporary quarters. The epidemics started during the Continuation war with positional warfare http://www.malariajournal.com/content/7/1/171 . Two weeks ago I collected mosquitoes in Finnish Lapland (69 degree N latitud) and got 300 Anopheles per night.

Buffoon
June 17, 2010 8:28 am

How does lowered precipitation (supposedly) affect the standing water that most mosquitos require to breed?
How do increased wind systems (supposedly) affect the ability of mosquitos to spread to and survive in non-forested regions?
How do rapidly extincting species (supposedly) affect the ability of mosquitos to obtain sustenance?
How does the invasion of shore-coupled sea-level swamp and marshland by ocean fish from sea level rise (supposedly) affect the ability of mosquitos to breed in temperate coastal regions?
How do chemical agents like DDT and logical methods like mosquito nets (confirmedly) affect the ability of mosquitos to spread deadly infectious disease?
In the immortal words of Darth Mathematician:
I sense a feedback disturbance in the Model.

Steve P
June 17, 2010 8:31 am

Pamela Gray says:
June 17, 2010 at 7:54 am


The solution? Get a cat.

Maybe not.

How many birds do feral cats kill?
Again, estimates vary, but even if each cat killed only one bird each year (studies have shown that some cats kill up to 1000 animals each year), it’s clear that hundreds of millions of birds are dying. Add to this the toll taken by roaming domestic cats (pets that are allowed to roam out of doors), thought to also be in the hundreds of millions, and you begin to comprehend the catastrophic effect that Felis silvestris is having on bird populations. If you also consider all the other threats to birds created by humans – habitat destruction, pollution, automobiles, cell phone towers, wind turbines, tall buildings, airplanes etc. – it seems a miracle we have any birds at all.

How many?
Just sayin’.

tty
June 17, 2010 8:47 am

There is no need to use DDT, drain swamps or even try to control mosquitoes to eradicate malaria. In most of Europe it went extinct long before DDT was introduced and the taiga zone in northern Europe and Siberia still has vast swamp areas and even vaster numbers of mosquitoes (including Anopheles, which transmits malaria), but no malaria. As a matter of fact mosquitoes in the tropics are not nearly as numerous as they are in the taiga.
It is largely a matter of living conditions and housing.

Nonegatives
June 17, 2010 9:29 am

Saw a bumper sticker on a car with Alaska plates in Florida:
“There is not a single mosquito in Alaska. They are all married with very large families.”

Robert Kral
June 17, 2010 9:55 am

Um, Pam, owls eat mice and rats. Big-time.

Dave Springer
June 17, 2010 10:07 am

What happens to the severity of cold and flu season in a warming world? You don’t hear warmists talking about that for some strange reason.

Reed Coray
June 17, 2010 10:47 am

e_por says:
June 17, 2010 at 2:14 am
The reason for more bites of mosquitoes in warmer places has nothing to do with heat affecting the mosquitoes, rather the heat effect on people:
When it is hot, people wear less clothing, especially at night (even the modest people wear less at home). That way the mosquito have better access to human flesh.
Elementary.

Sounds reasonable to me. Even if it’s not the primary reason, it sure needs to be factored into any calculation. Just like the question: Why do most shark attacks occur in shallow water? Answer: “It’s where the people are?”

Scott
June 17, 2010 11:33 am

Let them believe their crazed just-so stories about stuff like this. If it’s true, then as temperature goes up, so do mosquitoes, so does malaria…thus lowering mankind’s numbers, carbon emissions, and thus temperatures.
See? Another negative feedback. 🙂
-Scott

AC
June 17, 2010 12:10 pm

On the use of DDT. As we are aware at this site, after a certian ‘size’ what we expect isn’t always so (take global warming!).
DDT is great for a year or two, but after that, it isn’t effect and has to be cycled out of use. The problem is that in large population you have a certian amount who are immune to any hazzard (small pox, aids, toxins, etc). Guess which set of genes get passed on to the next generation? the ones that are immue to DDT.
This has been known since the early 1960’s. Big companies (like GE) who were trying to control miquitoes at their coorporate locations were finding that the DDT seemed less effective each year. A particular professor of entomology at a specific university would get these calls and tell them ‘guess which genes get passed on?’ I know more about him than this, like he told his students ‘where ever you go, when ever you get an insect, catch three, one for your collection, and send the other two back to me for the university collection and my collection.’
What does this mean for us and DDT, let’s use it this year and next, while we work on the next toxin because that is about as long as it will be good for until the gene pool gets reshuffled.

Douglas DC
June 17, 2010 12:12 pm

Early Explorers to the Pacific NW of the US, noted that the Natives cooked willow bark for the medicinal properties-Quinine in partcular…-for Malaria …

Gary Hladik
June 17, 2010 12:14 pm

Paul (June 17, 2010 at 6:27 am), great minds think alike! I, too, was wondering if the malaria stats hoisted the alarmists on their own canard, so to speak.

Editor
June 17, 2010 1:55 pm

With more money and energy (concrete and power and pipes and transportation and electricity for water treatment plants, pumps, and sewage disposal) we could eliminate cholera as well.
But that would save people’s lives, instead of cap-and-tax carbon trading funds going to corrupt 3rd world dictoator private funds.
And some 2nd world dictators.
And quite a few 1st world democratic politicians’ well-funded allies as well.

1DandyTroll
June 17, 2010 2:10 pm

One thing I find truly odd about the whole malaria scare connection to global warming is that apparently in the greenies magic ball of the horrid future absolute the mosquito has converted to liking dry and hot weather with not much rain and no moist and humid climate in general, instead of just rainy days with not too hot temperatures and preferably very moist and humid climate in general.
So if the greenies scenario of earth getting run over by mosquitos the it would also mean we’d get more rain in more areas, and a moist and humid climate in general, with not too hot temperatures. Uhm, isn’t that a climate change that the better part of the African continent, and several Arabic nations, and Persia, and parts of China, oh and Russia, and Australia, and parts of US, ah yes and Mexico, oh sod Spain, France, and Portugal, really needs, or rather needed yesterday already? Hmm funny how the mosquitos need for proper climate meet the human agriculture need for better climate. :p

Z
June 17, 2010 2:40 pm

Pamela Gray says:
June 17, 2010 at 7:54 am
I’ve even tried live traps. Took two days to get my Jack Russell’s head out of it.
The solution? Get a cat. Perfect pest control solution.

And what’s wrong with your Jack Russell killing vermin?

June 17, 2010 4:25 pm
Robert Kral
June 17, 2010 9:42 pm

AC, you misunderstand the way in which DDT is used now to control malaria. It’s used to treat surfaces in houses (maybe external surfaces, too, not sure about that). The mosquitoes that come into close proximity with sleeping people (the highest risk time for pathogen transmission) hit the DDT first and die before they bite. Not enough of the total moquito population is exposed to the DDT to create the kind of selection pressure that would generate a resistant population. It’s not foolproof, but it’s a damn sight better than nothing. A lot of enviros basically regard Africans as expendable- disturbing but true.

Christoph
June 17, 2010 10:23 pm

I do think if a man is going to post a 2-hour presentation on the internet both attacking someone’s work and attempting to discredit them, then that man should respond to letters from the person whom he targeted in his presentation.

thethinkingman
June 18, 2010 8:18 am

Just as AIDS was and is a political problem, so will Malaria become one.
Lots of people will die if Malaria is connected to the political bandwagon that is Agw.

Rodders
June 18, 2010 3:00 pm

>>Peer reviewed whack a mozzie
Would love to oblige, but they would shout ‘racist’ at me….

E.M.Smith
Editor
June 20, 2010 12:11 am

The maps are nice, but not in their time frame is the Gold Rush ’49ers malaria data.
California was (and is) Malaria country. Though now it’s down to something like 2 cases in the North end of the Sacramento Valley in the last decade or two. (Near my old home town on the Feather River…) Seems that we have a native mosquito that carries Malaria just fine, thank you very much, and lives up to (and over) 6000 feet AGL. That is serious snow country here. ( Squaw Valley is 6200 feet in the parking lot area).
So back in the 1840’s there was a darned high rate of malaria among the gold miners. They were dropping like flies. Even up in the high cold mountains. And that is why the University of California has a world class malarial disease program. As a result of that program, there is darned near no malaria left in the state.
In grammar school we were taught to dump standing water. To put mosquito fish in ponds. To screen windows. Etc. All the dull boring public health activities that DO matter (unlike the AGW scare that is just an attempt to frighten the children into handing over more money along with the lollypops…) Heck, we even had the county mosquito abatement district out running trucks up and down the streets with ‘foggers’ on them. Don’t know what pesticide they used, but it would fog up the whole town and drive the blood suckers out ‘right quick’. As a kid, we liked to go play in the fog behind the trucks… Yeah, probably a bad idea… On the other hand, never got mosquito bit on those nights (or often for a few days after ;-0
So you could add to those maps a bright green California (if you extended the time back to the early 1800’s) with the difference map having a deep blue as it was eradicated by your 1900 map that shows nothing left by then (and it stays gone during the warming into the intense 1934 era too!)
All during the ‘warming’ out of the little ice age
So California stands as a very shining example of how simple public health actions can eradicate Malaria in the face of a modestly strong warming trend. It also serves as an example of how malaria does just fine in high cold mountains too… if you don’t have good pubic health policies.
The notion that warmth causes malaria to spread is simply and flatly wrong.
The conclusion that Global Warming will cause any damage at all via malaria is simply bad propaganda.

AC
June 21, 2010 1:08 pm

Kral says:
June 17, 2010 at 9:42 pm
“AC, you misunderstand the way in which DDT is used now to control malaria. It’s used to treat surfaces in houses (maybe external surfaces, too, not sure about that). The mosquitoes that come into close proximity with sleeping people (the highest risk time for pathogen transmission) hit the DDT first and die before they bite. ”
I will admit that I don’t know about the application as I am getting the story of the Professor 2nd hand from a source that I trust. However your example sort of proves the point. If there are any misquites who get through the DDT to the sleeping people to take the blood they are by default the ones who aren’t succeptible to the DDT. As I said the major companies were in the early 60’s (or late 50’s) using DDT to control the buggers a lot more broadly than we would today – particuarly in applicaiton methodologies. And these companies were having problems and went to an expert for how to deal with them. He told them to change things up since the DDT was becoming ineffective. This is not the only bug toxin that has had that problem. Many have which is part of why today’s can or RAID probably is different in composition yesterdays.