Climate change could drive to extinction as many as one in six animal and plant species, according to a new analysis.

In a study published Thursday in the journal Science, Mark Urban, an ecologist at the University of Connecticut, also found that as the planet warms in the future, species will disappear at an accelerating rate.

“We have the choice,” he said in an interview. “The world can decide where on that curve they want the future Earth to be.”

As dire as Dr. Urban’s conclusions are, other experts said the real toll may turn out to be even worse. The number of extinctions “may well be two to three times higher,” said John J. Wiens, an evolutionary biologist at the University of Arizona.