We're talking specifically about tritium. Under normal circumstances, there's maybe 4 kilograms on the Earth's surface. The nuclear tests increased that by mu

We're talking specifically about tritium. Under normal circumstances, there's maybe 4 kilograms on the Earth's surface. The nuclear tests increased that by multiple orders of magnitude, ejecting hundreds of kilograms into the stratosphere, whereupon it promptly precipitated back out into the earth's oceans. 1) Your link does not discuss tritium. Tritium is a specific substance with specific characteristics; you can't just lump it all under "Evil Radiation" and make meaningful conclusions. 2) Whatever effect tritium would have would be global. You talk about local extinctions, but we're actually looking for evidence of massive global extinctions. The early 1960s (which saw peak tritium levels) are not known for a huge spike in inexplicable extinction events. 3) Not only did the tests spread it everywhere, but ongoing runoff means that rivers have been pumping tritium into delta regions. Almost a kilogram of tritium was pumped into the Gulf of Mexico over the last 50 years. Again, no impacts from the tritium have been detected; whatever impact it might have had was drowned out by all the other much more serious crap we humans were doing. 4) Again, there's still no theory as to how tritium (specifically tritium, and not, eg, radioactive cesium or iodine) might do all this crazy stuff. I'm just pointing out that there's also no emperical evidence either, and thus, no real reason to think our entire understanding of how radiation impacts living organisms is wrong. All of which means that people worried about the impacts of 4 grams of tritium on the Pacific Ocean are—to be charitable—innumerate. They're certainly wrong, because we've already dumped something like a HUNDRED THOUSAND TIMES more tritium into the Pacific ocean than that, and we literally have been unable to detect any impact. It's absurd to think we could even measure the impact of 4 grams.