According to the U.S. Forest Service, trees offset annual carbon dioxide emissions from fossil fuels by about 15 percent.

根据美国林务局的数据，树木每年抵消料产生的二氧碳排放量约15%。

So while higher concentrations of CO2 are being trapped in things like Antarctic ice, the changing ratios of isotopes will be detectable in fossilized trees, bones and shells far into the future.

因此，虽然更高浓度的二氧碳南极冰层等物体中，但遥远的未来， 树木、骨骼和贝壳中仍可检测到同位素比例的变。