"We should take this as a warning that climate change may affect the carbon cycle in previously unexpected way", says Beck.
Welcome to the K12 section of the Radiocarbon WEBinfo site.
All plants and animals on Earth are made principally of carbon.
During the period of a plant's life, the plant is taking in carbon dioxide through photosynthesis, which is how the plant makes energy and grows.
The team speculates that a supernova shock wave could have produced a flurry of cosmic rays.