WASHINGTON — Continuing to burn fossil fuels at the current rate could bring atmospheric carbon dioxide to its highest concentration in 50 million years, jumping from about 400 parts per million now to more than 900 parts per million by the end of this century, a study warns.
And if greenhouse gas emissions continue unabated beyond that point, the climate could reach a warming state that hasn’t been seen in the past 420 million years.
Some research suggests that, if humans burned through all fossil fuels on Earth, atmospheric carbon dioxide concentrations could hit 5,000 parts per million by the year 2400.
The new study speaks to the power of human influence over the climate. It suggests that after millions of years of relative stability in the absence of human activity, just a few hundred years of anthropogenic greenhouse gas emissions are on track to cause unprecedented warming.