BISBEE, Ariz. — Boots dusty, lungs heaving, Dr. John Wiens searched the boulders of a desolate Arizona mountaintop for the last survivors of a 3-million-year-old lizard population — then said the words that both confirmed his life's work and broke his heart. 'They're not there,' he said. 'It seems like the species is now extinct.' The loss of plant and animal species on Earth is happening at a speed never seen in human history, according to the United Nations.
' In March of this year, a survey trip into the mountains with CBS News proved his hypothesis correct, one year ahead of schedule. Wiens could no longer find any lizards, though it will take several more trips before rendering a conclusion. 'It seems like the species is now extinct, this distinct lineage that's been separated for about 3 million years,' he said. 'This is what the future is going to look like. This is climate-related extinction.