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Comment by danieltillett | Hacker News Reader

The sooner we get serious and start to deal with mosquitos the better. We already know what needs to be done [1], now all we need to do is get on with. How many millions of people have to die before we solve the problem of mosquito borne disease once and for all. Are we really going to sit around for decades debating if we should use this technology or not?

Edit. For those who want to understand more about this gene driver approach (it is pretty complex and amazing genetics) this review is the best I have been able to find [2].

1. http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.343...

2. http://longnow.org/revive/wp-content/uploads/2015/02/Alphey-...

View on HN

This will be Brazil first (southern) summer having to deal with a triple epidemic (zika virus, dengue and chikungunya fever), all due to the Aedes aegypti mosquito. Translating from a December 11th BBC Brasil article [1]:

"Two promising biotech projects have been tested in Brazil over the past few years, however, the results still aren't being felt on a large scale. The first one, betting on an insect inoculation scheme with a bacteria (Wolbachia) that stops the transmition of tropical diseases, is still in test phase and its impact will take 3 to 5 years to be evaluated.

The strategy behind the second project aims for the extermination of the species in certain regions via the use of genetically-modified mosquitos. The technique is said to have been tested successfully, according to the company that makes the transgenic mosquito - but it caused an uproar in the city in Bahia that served as the test ground. Even so, a city in São Paulo adopted the program since April, with promising results."

http://www.bbc.com/portuguese/noticias/2015/12/151210_combat...

Yes these approaches have potential - the problem with them is the cost is much higher than using a CRISPR-Cas9 gene drive system. From the BBC article "As the mosquito only lasts a generation, it is necessary that the environment is continuously fed by new GMOs until it reaches the extermination.” This costs a lot of money and would not be able to implemented in most countries. If a country can’t afford to spray then they are not going to be able to continually release GMO mosquitoes.

With the CRISPR-Cas9 gene drive approach once released it spreads through the mosquito population on its own - it really is a one-and-done approach. It is also relatively easily adapted to every mosquito species we want to go after. This work truly is world changing.

Have we ever on-purpose driven another species to extinction in order to save ourselves?

Smallpox is the classical example of this, but most large predators (wolves, bears, etc) have been driven to extinction in locations where humans are found in large numbers.

You could argue that the Tasmanian tiger was driven to extinction for commercial reasons as it was hunted to protect sheep flocks [1].

1. https://en.wikipedia.org/wiki/Thylacine

Also, the Guinea worm eradication program is getting quite close to succeeding. (http://www.healthmap.org/site/diseasedaily/article/guinea-wo...)

To save, maybe not. But we sure did it for other reasons -- like say to hurt others, or for economic reasons. One example is:

https://en.wikipedia.org/wiki/Bison_hunting

We went from 30 million on North American continent around 16th century, to a few hundred around 19th century.

We were trying to exterminate the American Indian.

I implied it only, but yes that I believe that was the goal.

Pretty much the goal with the secondary goal to force the Native Americans to stay on the reservations where food was distributed (couldn't give good farm land to them else they might get self sufficient).

Smallpox is the best example. Today, it exists only in closely-guarded labs. In prehistory, we also wiped out all the megafauna outside Africa --- partly because they were delicious, I'm sure, but also partly because they found us delicious.

Just about every large predatory animal ever.

The polio virus comes to mind.

We haven’t quite got there yet, but I hope we do soon [1]

1. http://www.nytimes.com/2014/05/06/health/world-health-organi...

Neanderthals. Perhaps it can be considered first world war.

Most big cats in Europe. Possibly Aurochs.

I haven't heard much about CRISPR-Cas9 in population studies/experiments like this - my understanding was that you need to insert the RNA. Since RNA is so unstable it is usually a 'one shot' process transfecting cells with plasmids through infusion.

Is the proposed mechanism to release a virus with the appropriate RNA scaffolds in the wild?

This strikes me as extremely dangerous

No you introduce it into the genome of the mosquito and then release the mosquito. No virus involved. It is best to read the paper and its references.

What makes you think it is dangerous?

I haven't seen the paper. Was it referenced in this thread?

If you're just genetically engineering the mosquito to be unable to transmit the virus, I can't see the harm in it. But if you are releasing a virus to act as your vector for genetic modification of the mosquitos, then I would think that has the potential to veer wildly off plan

The paper is linked at the top of this whole thread. The technology could be used to prevent transmission or drive the mosquitos to extinction. Preventing transmission is harder because there are so many diseases to prevent.

How do you think it might veer wildly off plan?

My bad re article.

Using a virus as a vector? The highly mutable nature of a virus. It's been engineered to perform a specific function, and within some limits of mutation it will still perform that function. There's a wide range of further mutations that will perform no noticeable function, and then there's a small space where it might do something that no-one expected. I mean, let's not get all doomsday about this - viruses are mutating and changing and leaping species all the time. We never know what nature will do for itself and how those effects will percolate through ecosystems.

My strongly held view is that we should be not be engineering with vectors. I do and have for a long time believed that species engineering (such as with this proposed system, although I was unaware of it until just now) is the way forward.

When I was completing my Biochem major I used to dream about ways to engineer our pestilent species out of existence, rabbits, cane toads and carp. Although in 2009 CRISPR wasn't even published and most of my thoughts revolved around chromosome engineering and X inactivation schemes to wipe the males of the species out. Not surprisingly, I wasn't the first to think of it and there was some great research out on those subjects

Can you explain what the advantage of the gene drive system is here? Looking at the paper, I see "Cassette exchange progeny" was only successful 0.05-0.38% of the time (table 1). So they need ~10,000 flies to get 10 mutants. Then in Supp Figure 3 I see detection of the "modified" DNA in the WT flies, and Figure 1c shows a good proportion of WT flies (denoted as "+/+" in that figure) were infertile as well!

So it seems if we just select those pre-existing infertile mutants we can get the same effect as using all these gene modification and gene drive techniques. I don't see what the advantage is supposed to be.

Sorry for the long delay. I think the problem is you need to understand what a gene drive is to understand the significance of this work. Have a look at the second paper I linked to and also George Church's I link lower down.

My wife works in research on vector borne disease, mostly mosquito carried viruses. Oddly, bourbon, heartland and lacrosse are becoming more interesting because they impact Americans. Many people have never even heard if them. Dengue, chikungunya, zika kill more people and are better known but they don't kill the people that fund the research.

It's an ugly situation. Dengue in particular was a real mess until relatively recently, like they didn't even gave consistent mechanisms to detect it or identify the different subtypes. Like you might test positive if cdc tested your blood but negative if a doctor in South America tests you. Really one of two things would be best for it, either climate change brings it in to Europe and North America or some tropical countries become serious enemies so the DOD takes it more seriously since they'll plan on fighting in places with it.

Didn't one or more of Dengue, chikungunya, zika make it to the US Virgin Islands? I would imagine that would get some well off Americans to take notice.

In Brazil's case, as least, it's simpler than that.

Mosquito eradication used to be done at the federal level, with military like organization. It kept things in control.

A few years ago it has been re-assigned to municipalities. Not only are local authorities less equipped to handle it, but mosquitoes do not conform to city boundaries. If one city is doing a good job but it's neighbor isn't you're screwed.

There's probably lots to be done through technical advances, but most of this could be avoided using common sense.

It is not a case of do one or the other, but do both.

Note that it is far from clear [1] is what needs to be done. [1] introduces sterility using gene drive. Sterility is effective but in a sense self-defeating, and it can only suppress, not eradicate, mosquito population.

[2] demonstrates introducing malaria immunity using gene drive. To attack malaria, it is enough to immunize mosquito against malaria, instead of eradicating mosquito. Immunity is also not self-defeating and can reach 100% fixation.

2. http://www.pnas.org/content/112/49/E6736.full

With multiple gene drivers you can drive a species to extinction - the power of CRISPR-Cas9 gene drive system is that you can make multiple different drivers easily.

Yes you can use gene drivers to create immunity in mosquitos against carrying certain diseases, but that only targets one disease at a time. Better to remove the vector rather than try to make the vector less dangerous.

This paper by George Church is a pretty good overview [1].

1. http://biorxiv.org/content/biorxiv/early/2014/07/17/007203.f...

Thanks for the link. That article mentions a plan where A) a vector species is eliminated and B) the species is repopulated from "clean" populations that have been simultaneously been kept alive in a lab/farm. Supposedly this will eradicate the parasite and its host while (probably?) allowing the reintroduction of the host species in the future without all the nasty parasites.

I suppose if the parasite rears its head again you could try rinse & repeat or just eradicate the host species and not bother to give them another chance via repopulation from a clean source.

EDIT: This eradicate everything, followed by a reintroduction of a "clean" population certainly sounds nicer than plain eradication. I worry about how an ecosystem can gracefully handle a rapid fire extinction/reduction and reintroduction.

Even if that isn't feasible, we would behoove ourselves to think about creating a Naughty Species Bank of populations of species we want to eradicate, before we actually attack that species. I'd be worried that we cannot re-introduce the original species if (when?) we encounter an "Oops... turns out that was a bad idea..." situation.

Yes as long as we kept some of the species alive we could always choose to repopulate the environment later if it turned out some extremely unlikely catastrophic result occurred.

Personally I think the only good blood sucking mosquito is a dead one so I doubt I would want to see them back even if they didn’t kill people.

Yes, gene drive can be used for extinction. No, the article you originally linked and said "we already know what needs to be done", is not for extinction.

By we I mean humanity, not the authors of the paper. They tended to hide behind sciencese in regards the significance of their work and didn’t go too much into its importance - the English don’t like to boast in public about themselves :)

What is important is they have showed how you can achieve extinction - we have known for a while that it was possible in theory, but there has not been a practical way of achieving this. We now have a practical way doing this - basically there are no limit to the number of genes you can target with the CRISPR-Cas9 driver system. Target enough and the species goes extinct.

If this approach is implemented it will save millions of people - every day we delay means another 3000 people die.

Are we sure wiping out a mosquito will not wreak havoc? Eg (just an hypothetic illustration) starving out a spider species which results in another nefast insect to proliferate? Are we sure the mosquito is not a key element in the ecosystem? Really curious to know more on this.

Yes we are as sure as we can be about anything in science [1], but even if it did cause some ecological issue it would be worth it given the misery mosquitoes cause.

1. http://www.nature.com/news/2010/100721/full/466432a.html

We need to make mosquitoes extinct, just like we made smallpox extinct.

We don’t even need to drive all mosquitoes to extinction, just the species that carry human diseases. If it is really so important to people that they survive then we could put some on an island as a kind of zoo.

Actually, we should wipe out only the 200-odd species that feed on blood. We can leave be the other ~1800 species.

Some biologists say we could wipe out all mosquitoes and it would make little difference to the ecology; there are enough substitute prey items. But I don't even care about that. Genocide them now!

> If it is really so important to people that they survive...

I very much like where you're going with this...

> then we could put some on an island as a kind of zoo.

wait, what??

The mosquitos, I think he meant.

Well, the people who like mosquitoes can go, too.

I was trying to be sly here by being ambiguous, but yes I mean the mosquitoes.

Ah, thank you..

Then again, they have wings; and, sea levels both rise and fall...

Sure. We don't need extreme specificity though: I'd be content with wiping out the whole family if that's what it takes to hit the ones that prey on humans.

The world needs more bats. While bats will eat other more nutritious insects like moths, wasps, etc. before mosquitos, they can help control the mosquito population in areas where there are many mosquitos, and most of the insects they get rid of are a nuisance to humans: http://www.mosquito.org/faq#bats

I wasn't aware of that. Where I live, in a mountainous area of Thailand, we have lots of bats, small insect eaters to large fruit eaters. It's quite a show around sundown watching them swoop overhead.

We also have lots of mosquitoes and the population sure isn't dwindling. We've got the aedes aegypti and there have been a few cases of dengue in my area. I don't think bats are going to solve the problem.

https://www.batcon.org/pdfs/bathouses/MosquitoControl.pdf

"Individuals of some bat species can capture from 500 to 1,000 mosquitoes in a single hour and large colonies can consume tremendous quantities. For example, a Florida colony of 30,000 southeastern bats consumes 50 tons of insects annually, including over 15 tons of mosquitoes and from 77.4% to 84.6% of little brown bats living in the northern U.S. and Canada eat mosquitoes."

Bats don't get rid of mosquitoes completely, but the right species of bat can be great to have to help keep their numbers down.

While I am generally pro-bat, I don’t think bats are going to solve the mosquito borne disease problem. If DDT couldn’t do it then bats aren’t going to be able to either.

DDT almost did it, then it was banned.

Focusing on practical approaches seems to yield most beneficial results. I have had very good experiences in tropical climates with window screening, mosquito nets, bio-compatible repellents, traps, zappers, and would like to find more good tools.

Not to be harsh did you read the article I linked to? Basically it shows us how we can wipe out all mosquitos for good without any pesticides or on going costs (it is a one-and-done approach). A world with no mosquito borne disease sounds like a pretty good idea to me.

To head off the ecological discussion about using this technology, mosquitos that carry human disease play no important ecological role and if every single one disappeared tomorrow the only consequence would be millions of people would stop dying. Over 700 million people a year get a mosquito borne disease and over a million die [1]. To stop this I would gladly sacrifice every mosquito.

1. https://en.wikipedia.org/wiki/Mosquito-borne_disease

http://www.nature.com/news/2010/100721/full/466432a.html

Yet in many cases, scientists acknowledge that the ecological scar left by a missing mosquito would heal quickly as the niche was filled by other organisms. Life would continue as before — or even better. When it comes to the major disease vectors, "it's difficult to see what the downside would be to removal, except for collateral damage", says insect ecologist Steven Juliano, of Illinois State University in Normal.

The collateral damage they are talking about here is avoided human misery and death. This is one sort of collateral damage we can happily live with.

I think they mean something more along the lines of Dragonflies. They love to eat mosquitoes and their larvae.

Not that we shouldn't do it, I'm sure they can live off knats just as easily.

I am pretty sure they were talking about people. From the Nature article

"The ecological effect of eliminating harmful mosquitoes is that you have more people. That's the consequence," says Strickman.

There's a certain strain of environmentalist that sees deindustrialization, technological regression, and human population decline as the solution to the world's problem. This perspective misses the mark, I think.

Human population decline would solve a lot of our environmental problems and is not necessarily tied to technological regression. In many developed countries it happens by itself and it could rather easily be helped along with some financial incentives, say, a tax on children.

The last thing we need is a tax on children in societies with sub-replacement fertility. A world without growth is a terrible place. (Before you object: yes, economic growth isn't the same as population growth. But to get economic growth with a declining population, you need productivity to grow faster than the population declines, and we're already having trouble keeping productivity growth up.)

http://www.nytimes.com/2015/12/02/business/economy/imagining...

why does productivity need to go up if the population is declining? what about the unemployed?

I have yet to study if these pests have any benefit, so I can only speak from experience. I dislike them intensely. Since you mentioned a possible solution, I checked to see how well it could do in terms of simplicity, effectiveness, and efficiency. From what I could tell, it would require an impractical[0,1,2] approach; and since I live among mosquitoes, I need to guard against illnesses like these.

0: overly-complex · genetic re-engineering of a wild species

1: ineffective · look at other attempts to control Nature through domination (usually, they backfire)

2: inefficient · I can barely imagine a technology we could manufacture that could do this simultaneoulsy in every affected area where humans and mosquitos live... even then, see again my point on ineffective

In regards your three points

0. CRISPR-Cas9 is an amazing simple system that has worked in every species tested. It really is not an issue to generate gene drivers for every species we want to go after.

1. How do you know it is ineffective? Do you understand how a gene driver system works? Arguments against attempting to control nature are rather weak - modern life is a successful attempt to control nature.

2. This is the genius of gene drivers. You let them go and they do all the work for you. We only have to release the driver into the mosquito population and it will do everything from there on its own.

This technology really is a massive game changer - we just have to be brave enough to use it.

> CRISPR-Cas9 is an amazing simple system that has worked in every species tested.

But how could we put it into practice? I only saw gene-level mechanics in that article. Please show me a machine that could do this at scale.

> modern life is a successful attempt to control nature

How so? I imagine 2,400 mothers in Brazil might have another story.

>But how could we put it into practice? I only saw gene-level mechanics in that article. Please show me a machine that could do this at scale

Figure 1C is what you need to look at. This is real mosquitoes, not genes.

I think the problem is you don’t understand what a gene driver system is and how it works (it is complex genetics so there is no shame in this). The wiki article [1] is not great, but the original article that raised this idea is complex, but worth reading [2]. The problem was until now we didn’t have a good system to actually make these drivers, we do now.

1. https://en.wikipedia.org/wiki/Gene_drive

2. http://rspb.royalsocietypublishing.org/content/270/1518/921

> The problem was until now we didn’t have a good system to actually make these drivers, we do now.

Link? Again, please show me a machine that can operate at scale or even a simple demo with an inlet, a re-engineered mosquito, and an outlet. (preferably without insulting me)

The population of the species and reproduction is the system itself. You introduce a new genotype to the population. This new genotype has recessive gene that causes sterility. Because it is recessive and not dominate, this new genotype will produce offspring and further spread the gene amongst the population. A female mosquito with two modified parents will be sterile, bringing about the goal of eradication.

EDIT: Regarding the last sentence, two recessive parents are not guaranteed to produce a modified phenotype offspring. My bio is getting rusty. :)

I am not trying to insult you, but you do need to try to understand what is being discussed.

I am pretty sure if you knew what a gene driver system is and what it can do then you would understand the significance of this paper. I edited my original post to include a link to a review paper that explores this whole area. You might find reading this helpful.

Ok, I see my misunderstanding. Gene driving takes both genetic engineering, like the process you pointed to initially, and it would require a catch-and-(selective)-release approach that works on guiding sexual reproduction (sorta like domestication, not gene therapy). (Aside: This reminds me of the TED talk https://www.ted.com/talks/paul_ewald_asks_can_we_domesticate... )

It makes a lot more sense to me when looking at it on a population level, rather than genetic. Emphasizing gene-level enhancements seems to inspire a "one-and-done approach" view, when as in the paper you added, its authors note several open questions they want to answer later (like these two):

* How can large numbers of high-quality modified insects be reared economically? In this context, how can insect quality be assessed?

* How should potential risks relating to the long-term instability/evolution of self-sustaining genetic elements be investigated, assessed and mitigated?

It seems, they have eyes bigger than their stomachs.

I will keep my eyes open to new tools from a wide range of fields. Influencing mosquito populations' genetics seems worthwhile, long-term. To get behind it, I simply want to see some practical approaches, like some phenotypic sorting tools, and some studies showing good mosquito DNA diffs. As related to this article, how/when could this work at scale in all parts of Earth mentioned here?

Excellent. In regards how to best target the mosquitoes using this system this is still an open question, but it is now an engineering and political problem, not science problem.

Unless he edited his post he wasn't being insulting. I'd say he was being very patient throughout this thread considering how demanding you're being.

There is a trial going on in Brazil right now using genetically modified males that cause the next generation to die. It has already reduced the Aedes aegypti mosquito population in one Brazilian suburb by 95%.[1]

If it can be shown that this approach doesn't lead to some horrible side effect, it holds great promise for reducing if not wiping out this invasive species to the Americas.

1. http://www.iflscience.com/plants-and-animals/dengue-fighting...

I'm from the Bay but lived all over Brazil during several years and never once saw window screens. Brazilians tell me they exist, though this goes against the very wide-array of living arrangements I had while there.

The Aedes Aegypty mosquito feeds during the day, so window screens and mosquito nets won't help them anyway, unless they don't leave the house.

What did you see them using? What do you mean by "very wide-array of living arrangements"?

They didn't use anything, aside from sprays and the sometimes-seen electric tennis racket.

Well, I have yet to find a Brazilian who has lived in as many places (in Brazil) as I have, either number of neighborhoods (15+) or cities (5). Also, I lived in many slums, in many middle class apartments, in a few upper-class places and even some hostels.

One of the most annoying things about the Aedes Aegypty mosquito is that it feeds during the day. That means mosquito nets and window screening are not enough, and people have to use repellents all the time.

Yes!

We would have solved this long ago if we hadn't given up on using DDT. We assumed it was a trade-off to save some birds, now it is more a trade-off to save humans vs birds.

This is a really complex topic, but DDT alone is not enough to remove mosquito borne disease. In some parts of the world you just can’t spray enough to make a difference even if you had a massive budget.

What prevents gene drive techniques from working on humans? The implications are disturbing, considering that humans have numerous ancestry-specific markers.

In principle they would work, but it would take thousands of years for a driver gene to spread through the human population. We also have the ability to do something about it and we could remove any driver gene from the population.

South Africa tried to develop a pathogen that would target black people during the apartheid era. This is certainly scary, but this is nothing to do with gene drivers like this.

You would not release a gene into the wild, but the CRISPR-Cas9 system. The long tail risk would be tremendous.

What would be the “long tail risk”? All the CRISPR-Cas9 systems would die out with the mosquitos.

We have 700 million cases of mosquito caused misery a year (along with more than a million deaths) on one side, and a completely vague risk that something bad might happen on the other. It is like worrying if you are going to get cancer from the smoke while your house is burning down.

> What would be the “long tail risk”? All the CRISPR-Cas9 > systems would die out with the mosquitos.

May I assume you have zero background in biology/biochemistry/chemistry?

No you may not (you can look at my profile here). Once again what is the long tail risk? Up thread there is lots of discussion about all of this.

A few points

http://www.nature.com/news/caution-urged-over-editing-dna-in...

http://arstechnica.com/science/2015/03/new-dna-construct-can...

http://arxiv.org/pdf/1410.5787.pdf

You release not only a gene but a technology into the wild. This is something that can not be undone. You may easily underestimate the scale, rapidness and evolutionary pressure of a fast replicating species. Throw a few atomic bombs on Brazil. The effects are

a) temporary

b) geographically limited.

If something screws up with the CRISPR/Cas9 system, the effects are

a) not temporary

b) geographically unlimited.

Proceed with caution.

Basically a warmed up version of the "precautionary principle” - or as it should be named "don’t do anything new because something bad might happen” principle. This is not an argument for any long tail, just an argument for inaction because we don’t know what might happen and can never know unless we try. If our ancestors had taken the same approach we would still be living in trees being eaten by wild animals.

What those propounding the precautionary principle forget is the do nothing approach is not cost free. 700 million people are made ill every year by mosquitoes and more than a million killed. Unless the risk adjusted consequences are greater than this then doing nothing is far worse. No one has been able to suggest any possible bad consequences of wiping out all human disease carrying mosquitos so there is nothing to be precautionary about [1].

As for the technology it is already in the wild - it was originally isolated from bacteria. One final point is yes it can be undone - see George Church’s paper [2]. George is on your side, but he does explain how any trial can be controlled.

1. http://www.nature.com/news/2010/100721/full/466432a.html

2. http://biorxiv.org/content/biorxiv/early/2014/07/17/007203.f...

"No one has been able to suggest any possible bad consequences of wiping out all human disease carrying mosquitos"

This was not the question.

But I see that "unlimited" risk is no problem for you. The problem I have is that I am sharing this risk for your actions. How about to try to get this insured? I am curious about the price quote for an "unlimited" risk that an insurance company would quote.

I think one of the major reasons for our disagreement is you perceive that there is an unlimited risk with GMO organisms - the paper you linked to explicitly states this [1]. Quoting from it:

Ecologically, in addition to intentional cultivation, GMOs have the propensity to spread uncontrollably, and thus their risks cannot be localized. The cross-breeding of wild-type plants with genetically modified ones prevents their disentangling, leading to irreversible system-wide effects with unknown downsides. The ecological implications of releasing modified organisms into the wild are not tested empirically before release.

The problem with this analysis is their assumption that GMOs have a propensity to spread uncontrollably. This is totally false. The problem with GMOs is they don’t spread very effectively unless under human selective pressure. The reason why is really simple - all organisms have a fixed metabolic budget which they can allocate to different functions (grow, reproduction, protection against predation, repair, etc). When you introduce new genes into an organism you have to take away some of this fixed budget to allocate to the new function. This means that when the GMO competes with other organisms in the wild they are at a disadvantage. If you make an argument based on a false assumption then you will get a faulty conclusion.

It is a real shame with this paper as the rest is quite good and an excellent argument for not doing things where ...the consequences can involve total irreversible ruin, such as the extinction of human beings or all life on the planet. GMOs just don’t happen to be one of these things (I am leaving out of GMOs things like creating new pathogens, but you don’t need genetic engineering to create these as the USA and Russia showed in the 1950 and 1960s).

The bottom line is GMOs are not that scary. In fact I know of no serious harm that has come from any other than to make people fearful for no reason and their absence to drive up the price of food.

1. http://arxiv.org/pdf/1410.5787.pdf

Just 40 years ago "global warming" was called "global cooling", and an ice-age apocalypse was predicted.

Imagine if the powers-that-be decided to do global scale climate geo-engineering by dispersing chemicals into the atmosphere (to increase the temperature).

> We already know what needs to be done [1], now all we need to do is get on with.

The good old thinking that you know everything and can't be wrong almost guarantees that you will be wrong.

> Just 40 years ago "global warming" was called "global cooling", and an ice-age apocalypse was predicted

That's rather misleading. As noted in the Wikipedia article on "global cooling" [1], which I know you are aware of because you cited it in the original version of your comment:

   This hypothesis had little support in the scientific
   community, but gained temporary popular attention due
   to a combination of a slight downward trend of
   temperatures from the 1940s to the early 1970s and press
   reports that did not accurately reflect the full scope of
   the scientific climate literature, which showed a larger
   and faster-growing body of literature projecting future
   warming due to greenhouse gas emissions.

Those who did support it generally did so not because they thought global warming was wrong. They just thought that smog levels would continue rising faster than greenhouse gas levels, so that the cooling affect that smog causes would be more significant than the warming effect greenhouse gases cause.

Their only mistake was not anticipating that we would actually start taking air pollution seriously enough to not only stop the smog rise but reverse it. Since the '70s smog levels have come way down.

[1] https://en.wikipedia.org/wiki/Global_cooling

The predominant theory with the media and general public was Global Cooling. You can quickly see this using Google Image Search and the news clippings ("Global Cooling").

Or just check this compilation - http://wattsupwiththat.com/2013/03/01/global-cooling-compila...

The point is they thought they were also very right.

>Just 40 years ago "global warming" was called "global cooling", and an ice-age apocalypse was predicted

No serious scientist ever thought we were going into an ice age 40 years ago.

>The good old thinking that you know everything and can't be wrong almost guarantees that you will be wrong.

Ad hominem arguments are not very helpful, but where exactly did I argue that I can’t be wrong? If you have an actual argument that shows I am wrong please post it. It has to be better than a warmed up precautionary principle.

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