I have no opinion about the threshold, but there are two things to correct in your post:

He is absolutely right though. It is the common view of the scientific community that no amount of ionizing radiation is safe. This is also the basis of all radiation protection regulation everywhere (ALARA principle). The reason is simple: Ionizing radiation creates DNA damage with a small probability which then causes cancer with a small probability (which has then a certain probability of killing you). So even a single particle has a very small probability of causing cancer. There is a minority of people that believe that there are other effects (e.g. radiation at low doses activates the immune system) which dominate at low doses, but this is a minority view point and the data we have does not support this. From atomic bomb survivors see a linear correspondence between dose and risk down to about 50 mSv. For example, from this it was predictated that CT scans cause cancer with a very low probability and this has recently been confirmed.

This is a fallacy. The threshold should be set on the estimated benefits of a higher threshold vs the estimated harm from the additional radiation. The background radiation has nothing to with it.

Good point. This is an effect which can happen in certain circumstances. But Germany grew its economy with stable energy consumption for decades. So obviously this did not happen in the past. It also depends on energy policy, so it can be actively avoided.

That seems to be a common idea here in the US. Do you have some actual numbers?

Comment is mine. Forgot to log in.

An electricity generating company investing in renewables might have a competitive advantage relative to its competitor. Ofcourse, if both invest in renewables there is no relative advantage anymore. But this does not mean that the tax had no effect in this case - quite the opposite!

Energy use in highly-developed countries such as Germany or United States has been more or less stable for the last decades with a slight downwards trend. This is expected to continue.

It is usually expected that highly-developed countries will use less power in the future, because of more efficient technology.

A carbon tax does not affect every business equally.

Nonsense Radiation from CT is a serious concern. A single abdominal or chest CT corresponds to a dose of 5-10 mSv. The is especially a concern for children and in case of repeated scans. For example, see:

http://www.ajronline.org/doi/a...
"In the United States, of approximately 600,000 abdominal and head CT examinations annually performed in children under the age of 15 years, a rough estimate is that 500 of these individuals might ultimately die from cancer attributable to the CT radiation."

Well, one could argue that the bureaucracy is required for safety.

Considering the state of the technology today, I agree that renewables cannot provide all of the demand today. But nuclear only provides baseload and so does not help.

Yes, also forcasts for nuclear have usually been very optimistic. The main cost of nuclear is the cost of construction which often went up a lot in actual projects. But even considering this it is not competitive with gas, wind, and hydro.

Creating a dramatic drop in prices. You have to compare it to what has been spent on nuclear so far.

The subsidies are meant to create a market which will then make solar (and other renewables) more efficient. This was very successful so far. Much more has been spent in nuclear in the past and it is still not competitive.

That is actually not true in Germany. CO2 production was stable. Also, don't you think we would produce a lot more CO2 if Germany had scaled up coal instead of renewables to replace nuclear? In the near future when renewables replace coal instead of nuclear, CO2 will obviously come down.

Huh, what makes you think it does not?