Editing Background radiation (section)

===Atmospheric nuclear testing===
[[Image:US fallout exposure.png|right|thumb|Per capita [[thyroid]] doses in the continental United States resulting from all exposure routes from all atmospheric [[nuclear testing|nuclear tests]] conducted at the [[Nevada Test Site]] from 1951 to 1962.]]

[[File:Radiocarbon bomb spike.svg|thumb|Atmospheric <sup>14</sup>C [[Bomb pulse]], [[New Zealand]]<ref>{{cite journal|url=http://cdiac.esd.ornl.gov/trends/co2/welling.html |title=Atmospheric δ<sup>14</sup>C record from Wellington |access-date=2007-06-11 |journal=Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center |year=1994 |url-status=dead |archive-url=https://web.archive.org/web/20140201222225/http://cdiac.esd.ornl.gov/trends/co2/welling.html |archive-date=1 February 2014 }}</ref> and [[Austria]].<ref>{{cite journal| url=http://cdiac.esd.ornl.gov/trends/co2/cent-verm.html| author=Levin, I.| title=δ<sup>14</sup>C record from Vermunt| journal=Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center| year=1994| display-authors=etal| access-date=4 January 2016| archive-url=https://web.archive.org/web/20080923105819/http://cdiac.esd.ornl.gov/trends/co2/cent-verm.html| archive-date=23 September 2008| url-status=dead}}</ref> The New Zealand curve is representative for the Southern Hemisphere, the Austrian curve is representative for the Northern Hemisphere. Atmospheric nuclear weapon tests almost doubled the concentration of <sup>14</sup>C in the Northern Hemisphere.<ref>{{cite web | url=http://www1.phys.uu.nl/ams/Radiocarbon.htm | publisher=University of Utrecht | title= Radiocarbon dating | access-date=2008-02-19}}</ref>]]

Frequent above-ground nuclear explosions between the 1940s and 1960s scattered a substantial amount of [[radioactive contamination]]. Some of this contamination is local, rendering the immediate surroundings highly radioactive, while some of it is carried longer distances as [[nuclear fallout]]; some of this material is dispersed worldwide. The increase in background radiation due to these tests peaked in 1963 at about 0.15&nbsp;mSv per year worldwide, or about 7% of average background dose from all sources. The [[Limited Test Ban Treaty]] of 1963 prohibited above-ground tests, thus by the year 2000 the worldwide dose from these tests has decreased to only 0.005&nbsp;mSv per year.<ref name="rrjhjx">{{Cite report |url=https://www.unscear.org/unscear/en/publications/2000_1.html |title=Sources and Effects of Ionizing Radiation - UNSCEAR 2000 Report to the General Assembly, with Scientific Annexes |last=United Nations Scientific Committee on the Effects of Atomic Radiation |date=2000 |language=en |access-date=2022-09-12}}</ref>

This [[global fallout]] has caused an estimated 200,000-460,000 deaths as of 2020.<ref name="s257">{{cite web | last=Adams | first=Lilly | title=Resuming Nuclear Testing a Slap in the Face to Survivors | website=The Equation | date=May 26, 2020 | url=https://blog.ucsusa.org/lilly-adams/resuming-nuclear-testing-a-slap-in-the-face-to-survivors/ | access-date=July 16, 2024}}</ref>