3 ms·

4,000 is based on a conservative linear-no threshold model across all irradiated populations [1]. [1] https://www.unscear.org/unscear/en/chernobyl.html https:/

4,000 is based on a conservative linear-no threshold model across all irradiated populations [1]. [1] https://www.unscear.org/unscear/en/chernobyl.html https://www.unscear.org/unscear/en/chernobyl.html The UNSCEAR is a UN group of scientists who study radiation, similar to the IPCC group studying climate. The fringe studies from Greenpeace and friends claiming more than 4000 deaths do not carry more weight than the UNSCEAR numbers.

gus_massa 6y ago
Just to clarify what "conservative" means here. Oversimplifying, if you distribute the radiation that was released evenly in a group of 8000 persons, each one has a 50% chance of dying, so you expect to see 4000 deaths. If you distribute the same radiation evenly in a group of 80000 persons, each one has a 5% chance of dying, so you expect to see 4000 deaths. If you distribute the same radiation evenly in a group of 8000000 persons, each one has a 0.05% chance of dying, so you expect to see 4000 death. But in the 8000000 group the radiation level is too low and there is also normal background radiation, and other normal risk, so the real number is probably less than 4000 deaths. In a realistic scenario, some people get more radiation and some less radiation, but the nice part of the simplified model is that it always predict 4000 deaths. But this number is like an upper bound, the real number of deaths is probably less.
- Retric 6y ago
  There is evidence that the linear no threshold model both over estimates and under estimates the increase in cancer deaths among humans. The disagreement stems in part from the extremely high rate of cancers and thus precancerous tissue among people which means than some tissue is unusually vulnerable. This is supported by skin cancer rates. The opposite conclusion is based on cellular responses to low level radiation exposure, which may provide protection from future exposure. If it was actually clear LNT was a bad model we would be using something else, but it’s not obvious which direction it should be updated. Presumably, the reality is some non linear effect relating to lifetime exposure for radiation and other cancer risks, but collecting accurate data is difficult.
Retric 6y ago
It’s important to understand the context for what’s being said. “given the low doses received by the majority of exposed individuals, any increase in cancer incidence or mortality will be difficult to detect in epidemiological studies.” Detecting an increase in cancer deaths from a specific source when cancers represent 1 in 6 deaths worldwide is extremely difficult. If cancer killed 100 people per year then detecting an increase of ~X00 extra deaths per year would be much simpler. On the other hand try to isolate ~1 extra cancer death per 10,000 deaths is a pipe dream.

gus_massa 6y ago

Just to clarify what "conservative" means here. Oversimplifying, if you distribute the radiation that was released evenly in a group of 8000 persons, each one has a 50% chance of dying, so you expect to see 4000 deaths. If you distribute the same radiation evenly in a group of 80000 persons, each one has a 5% chance of dying, so you expect to see 4000 deaths. If you distribute the same radiation evenly in a group of 8000000 persons, each one has a 0.05% chance of dying, so you expect to see 4000 death. But in the 8000000 group the radiation level is too low and there is also normal background radiation, and other normal risk, so the real number is probably less than 4000 deaths. In a realistic scenario, some people get more radiation and some less radiation, but the nice part of the simplified model is that it always predict 4000 deaths. But this number is like an upper bound, the real number of deaths is probably less.

Retric 6y ago
There is evidence that the linear no threshold model both over estimates and under estimates the increase in cancer deaths among humans. The disagreement stems in part from the extremely high rate of cancers and thus precancerous tissue among people which means than some tissue is unusually vulnerable. This is supported by skin cancer rates. The opposite conclusion is based on cellular responses to low level radiation exposure, which may provide protection from future exposure. If it was actually clear LNT was a bad model we would be using something else, but it’s not obvious which direction it should be updated. Presumably, the reality is some non linear effect relating to lifetime exposure for radiation and other cancer risks, but collecting accurate data is difficult.

Retric 6y ago

It’s important to understand the context for what’s being said. “given the low doses received by the majority of exposed individuals, any increase in cancer incidence or mortality will be difficult to detect in epidemiological studies.” Detecting an increase in cancer deaths from a specific source when cancers represent 1 in 6 deaths worldwide is extremely difficult. If cancer killed 100 people per year then detecting an increase of ~X00 extra deaths per year would be much simpler. On the other hand try to isolate ~1 extra cancer death per 10,000 deaths is a pipe dream.