Carbon-14 is radioactive, with a half-life of about 5,700 years.
For more information on cosmic rays and half-life, as well as the process of radioactive decay, see How Nuclear Radiation Works.
CDIAC's data holdings include estimates of carbon dioxide emissions from fossil-fuel consumption and land-use changes; records of atmospheric concentrations of carbon dioxide and other radiatively active trace gases; carbon cycle and terrestrial carbon management datasets and analyses; and global/regional climate data and time series.
We know that it is older than Christendom, but whether by a couple of years or a couple of centuries, or even by more than a millenium, we can do no more than guess." [Rasmus Nyerup, (Danish antiquarian), 1802 (in Trigger, 19)].
Scientists used carbon dating to show that the flutes were between 42,000 and 43,000 years old.
(Source) According to a 2006 report, Iranian archaeologists in "Burnt City" announced the unprecedented discovery of an artificial eyeball, dated to 4,800 years ago, in this historic site.
emissions estimates through 2014 are now available.
Revised (V1.1) 2016 global methane budget estimates from the Global Carbon Project are now available.