Photos Much Colder Now
But how the continent came to be so cold is something of a mystery. Around 14 million years ago, scientists are fairly certain the climate resembled modern-day Alaska. Within a million years a deep freeze had settled in, and the ice sheets grew to mammoth proportions, where they mostly remain today. The newly discovered Ostracod fossils confirm that the changes -- which until now had only been observed in ocean floor sediments -- were also playing out on land in Antarctica. "We've shown that this change in climate had a profound impact on Antarctica," Ashworth said. "The evidence tends to suggest the threshold of temperature was never reached again in that part of Antarctica. We'd argue that it's been locked down and frozen for the past 14 million years." Timothy Naish of Victoria University of Wellington in New Zealand agreed that the team's study was "important to our understanding of Antarctic climate." But he added that there's still a lot of uncertainty about what happened after the 14-million-year mark. "We see a lot of variability in climate, and there is evidence that a significant amount of the Antarctic ice sheets melted recently, around three million years ago," before freezing again, Naish told Discovery News. Related Links: Discovery News blog: EnvironMental Case |
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