How Many People Died (or Will Die) From Chernobyl? And, Population Risk vs. Individual Risk

By Chris Mooney | April 12, 2011 9:23 am

Aware of the big debate over this question, I wanted to dig into the topic with David Brenner of Columbia on Point of Inquiry. The exchange on this, which gets into the reasons why people disagree about the magnitude of the disaster, begins around minute 13:30 and runs on for more than 5 minutes.

I want to call attention to one part of the exchange in particular (stream here). After Dr. Brenner explained why there are such wildly varying estimates (from 6,000 to as high as nearly 1 million) for the Chernobyl death toll–it all has to do with whether you multiply very minimal radiation doses by the very vast populations that did get at least some tiny exposure to radiation from Chernobyl–I asked the following:

Chris Mooney: The World Health Organization studied Chernobyl, and they put a low end estimate on the number of deaths, so they were ruling out, essentially, these extremely low doses to extremely large numbers. Was that a valid thing to do?

Dr. David Brenner: “Valid” is a tricky word. Was it an appropriate thing to do? That’s a hard question. The best science that we have, I would suggest, cannot rule out the possibility that we should really include everybody who was exposed to extremely low doses. And if you do that, you end up with quite large population cancer burdens. That being said, that doesn’t mean that the individual risk to anybody was high. The distinction here is between individual risk–the risk that any one person gets from a tiny dose of radiation–and population risk, the risk to a whole population, the number of cancers that might be produced in a whole population. They’re different concepts. Population risk involves individual risk and the number of people exposed. Individual risk is just individual risk. Trying to make that distinction–it’s an absolutely critical distinction, and it’s one that gets lost in the flurry of debate.

Chris Mooney: But it’s even trickier than that, because it both implies that, “Hey, I’m in California, and something happened in Japan, so I individually don’t need to worry very much,” but at the same time, it gives ammo to those who will say later, well, it killed this ungodly number of people–which will scare people in the future.

Dr. David Brenner: Indeed, you’ve hit the nail very much on the head. But it is fair that one should look at risk from both of these aspects. It’s important to know what people’s individual risks are, but it’s also important to understand what the consequences for a very large population would be.

As you can maybe tell, I really don’t like the idea of these vast populations of unidentifiable victims. It bothers me. It doesn’t sound right.

However, Brenner explains why we can’t rule it out, and his explanation is very cogent. As a result of this, I’m now way more skeptical of George Monbiot. He’s treating the WHO study as if it is the right answer, but this issue of low dose exposures to very large numbers, while maddening and tricky, cannot be dismissed at this point. I’m not taking the side of his opponent, either; I’m not sure we dash to the extreme high end estimate either, but clearly, this topic requires caution.

Again, you can stream the latest Point of Inquiry episode here.

CATEGORIZED UNDER: Nuclear Power, point of inquiry

Comments (13)

  1. isaacschumann


    Your series on radiation risk has been excellent, thanks. How would these increased incidence of cancer in a large population compare to, say, smoking or obesity? (If this comparison is even possible or appropriate)

  2. But, I think that reducing it down to only the numbers of people who will die from radiation exposure is short sighted too. What about the secondary effects of forced abandonment of 750 square miles of land. OK, you’re not going to die 3 years early of cancer, but you have 1 hour to pack what you can and live in a shelter for 6 months until you can start over again without your farm and family land and way of life. And, as apopulation, you have an statistically elevated risk of future ailments. WoooHooo!

    There is life, and there is quality of life, and then there is mental, physical and social consequences that spiral outward from there. Ignoring that seems a little disingenuous. Doesn’t it?

  3. Sean Mitchell

    This is an interesting point. Has anyone looked into similar small risks for a large population for the Gulf oil spill, or for coal fueled power stations, or any of the other risky ways we produce energy?

  4. Eric the Leaf

    That, and many other reasons why nuclear power is probably not a viable option for our energy future. It is not a “simple” question of weighing the radiation risk. But that is what this series of posts has seemed to imply.

  5. Nullius in Verba

    Globally, about 150,000 people die per day, and 50 million per year. Over the 25 years since it happened that’s 1.25 billion people, and counted over a lifetime, it’s everyone. Given that most people live in countries where life expectancy is below what it is here in the West, it’s probably safe to say that most of those deaths are premature. Perhaps that helps put it into context?

    Never mind smoking and obesity – how does it compare to the death rate due to poverty? Or lack of energy security? When faced with a choice between alternatives that will all result in statistical deaths, how should we set our priorities?

  6. Jamesqf

    Re: “What about the secondary effects of forced abandonment of 750 square miles of land.”

    OK, but why is this worse than the forced abandonment of land because your government has e.g. decided to build a massive hydroelectric dam downstream?

    If you somehow evade the authorities and stay after a nuclear accident (as some people did after Chernobyl) you MAYBE* have an increased cancer risk. If you stay after the dam’s built, you’d better grow gills.

    *And there’s still no answer to the question of whether there’s really any increased risk at all from low exposures. It’s simply an assumption, which seems to be contradicted by studies of e.g. places where there’s a higher than average natural background, or the wildlife in the Chernobyl exclusion zone.

  7. crf

    “The best science that we have, I would suggest, cannot rule out the possibility that we should really include everybody who was exposed to extremely low doses.”

    Sure. Include them. But have the decency to emperically calculate the range of increased risk of cancer from those small doses. Then go out and try to independently validate your calculation by looking at the data. Do you see the increased deaths and cancers you thought you’d see?

  8. Alvin Hulse

    WHO was contacted by Dr. John W. Gofman regarding the failures and flaws of the Chernobyl Health Registry Database. Here is assessment by of the Database by Gofman. I have included his curriculum viate in case anyone doubts his impeccable credentials. The Department of Energy is now tampering with the Atomic Bomb Victims Database. Curriculum Vitae Chernobyl Faulty Database Assessment – Short Version Long Version

    Chris Mooney – Perhaps if you had had this information before you interviewed David Brenner, you could have asked him some tough questions.

  9. While the flood zone of a dam displaces a lot of land and potentially populations, there is a decision made in advance of it occurring and presumable more warning than a rumble, then a wave and finally a faint boom from a hydrogen explosion. But, you point is well taken. All forms of energy have risks and consequences associated with them. They go well beyond short and long term health risks.

  10. Here’s what I don’t understand about the whole “low dose” thing. The low additional doses we’re talking about are below the background dose you receive anyway. If you receive a dose that is (say) 5% of the background radiation for one year, then, yeah, you have an increased risk, presumably. But if we’re going to “blame” however many deaths are due to that increased 5%, then we need to “blame” the factor of 20 greater deaths that happened **on background radiation**. So, if we’re going to get wild-eyed about how many people distributed widely over the world died because of an additional radiation dose one year, to be fair we should get just as wild eyed over the order of magnitude (or two, or whatever) greater number of people who died “because of background radiation”.

    At some point you have to accept additional deaths as the cost of civilization. We certainly do for coal miners. In the USA, at least, and I suspect worldwide, the GREATEST number of deaths we accept as a “cost of civilization” are traffic accident deaths. If we really put those numbers up, we should be screaming out loud about banning the automobile. But, somehow, we as a society can accept these deaths as a background cost. Unless we want a whole lot more deaths from the collapse of civilization due either to massive climate change or runaway energy costs, we’re going to have to accept whatever background radiation deaths happen from nuclear accidents…. Barring an amazing breakthrough in fusion or in the cost of manufacturing solar panels, our choice is going to be nuclear power or … well, or giving up, really.

  11. Eric the Leaf

    Rob, I think this is incorrect, and you forward a false choice. Why? Because there isn’t a choice. Nuclear power is untenable, not specifically because of the health risks one way or the other, unless you also consider that a massive build-out of a nuclear fleet will demand a level of civil order and continuity without precedent. Consider also the need for hundreds of more reactors, just in the USA.

    Furthermore, nuclear power depends on a stable grid, supply chain, economy, and environment far more than it can help to create these things. It’s the most complex and least resilient way we could possibly contrive to bring us our basic power needs. It’s not just a scientific problem, it’s a societal problem.

    No, this will not occur, and the reasons are best summarized by Richard Heinberg, one of the world’s top experts in resource supply, particularly of non-renewable fuel sources. See, for example, pages 36-38 of the following report: “Searching for a Miracle: Net Energy Limits and the Fate of Industrial Society.”

    Heinberg recently contrasted two possible future energy scenarios, one based on a low-carbon energy path and the other based on a high-carbon energy path:

    The result of this thought experiment was essentially the same. The future will involve much less total energy one way or the other. Nothing will “save us” in the traditional sense of continuing business as usual. Give up? Well, that’s not what I would advocate, although it is something that I would recommend to anyone that would think that life is not worth living with anything less than the current level of energy consumption.

    What a great interview Chris could have with Richard Heinberg, probably the world’s leading journalist and educator on issues of resource availability and depletion, particularly on the occasion of the publication of his new book, which address The Intersection between economics, energy, and the environment.

  12. Jamesqf

    Re #9: “While the flood zone of a dam displaces a lot of land and potentially populations, there is a decision made in advance of it occurring and presumable more warning than a rumble, then a wave and finally a faint boom from a hydrogen explosion.”

    No, the rumble & wave is what happens when the dam fails, perhaps because it was built near a major fault, and you live downstream. (Folks in Portland, Oregon might take note.) So with a hydro dam, you have the possibility of disastrous failure at some time in the dam’s life (and how do you decomission a dam, eh?), plus the certainty that some amount of land (an area comparable to the Chernobyl exclusion zone) will be rendered uninhabitable – and unlike with a nuclear accident, unusable even as a wildlife refuge.

    So let’s reverse the process. Instead of having nuclear accidents create wildlife refuges, let’s put nuclear plants in areas set aside as refuges.

  13. Dark Tent

    “this topic requires caution.”

    …even from journalists, who sometimes (albeit only once in a blue moon) make claims before they understand the issues.


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About Chris Mooney

Chris is a science and political journalist and commentator and the author of three books, including the New York Times bestselling The Republican War on Science--dubbed "a landmark in contemporary political reporting" by and a "well-researched, closely argued and amply referenced indictment of the right wing's assault on science and scientists" by Scientific American--Storm World, and Unscientific America: How Scientific Illiteracy Threatens Our Future, co-authored by Sheril Kirshenbaum. They also write "The Intersection" blog together for Discover blogs. For a longer bio and contact information, see here.


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