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Global warming has propelled Earth's climate from one of its coldest decades since the last ice age to one of its hottest -- in just one century.
A heat spike like this has never happened before, at least not in the last 11,300 years, said climatologist Shaun Marcott, who worked on a new study on global temperatures going back that far.
"If any period in time had a sustained temperature change similar to what we have today, we would have certainly seen that in our record," he said. It is a good indicator of just how fast man-made climate change has progressed.
A century is a very short period of time for such a spike.
Far from natural warming
Variations in how the Earth is tilted and its orbit around the sun make for a pattern of planetary warming phases followed by cooling phases across the millennia.
The team's research shows the Earth's overall temperature curve dipping down over about the past 4,000 years, but the downward plod comes to an abrupt halt in modern times.
"If you were to predict -- based on where we are relative to the position of the sun and how we are tilted -- you would predict that we would be still cooling, but we're not," Marcott said.
Instead, the planet is warming up. It hasn't been quite this warm in thousands of years. And it's getting hotter.
By 2100, the Earth will be warmer than ever before, Marcott said. If emissions continue as currently predicted until then, global temperatures will rise "well above anything we've ever seen in the last 11,000 years."
That could be a rise of 2 to 11.5 degrees Fahrenheit, according to the NSF."
"The main culprit is carbon dioxide, and its levels have jumped in the last 100 years, Marcott said. In the 11,000 years prior, it only changed "very slowly," he said.
The last time Earth has been as warm as it is projected to be by 2100 was before the last Ice Age started -- over 130,000 years ago. That's too long ago to gather reliable data on, he said."
Global warming is epic, long-term study says - CNN.com
A heat spike like this has never happened before, at least not in the last 11,300 years, said climatologist Shaun Marcott, who worked on a new study on global temperatures going back that far.
"If any period in time had a sustained temperature change similar to what we have today, we would have certainly seen that in our record," he said. It is a good indicator of just how fast man-made climate change has progressed.
A century is a very short period of time for such a spike.
Far from natural warming
Variations in how the Earth is tilted and its orbit around the sun make for a pattern of planetary warming phases followed by cooling phases across the millennia.
The team's research shows the Earth's overall temperature curve dipping down over about the past 4,000 years, but the downward plod comes to an abrupt halt in modern times.
"If you were to predict -- based on where we are relative to the position of the sun and how we are tilted -- you would predict that we would be still cooling, but we're not," Marcott said.
Instead, the planet is warming up. It hasn't been quite this warm in thousands of years. And it's getting hotter.
By 2100, the Earth will be warmer than ever before, Marcott said. If emissions continue as currently predicted until then, global temperatures will rise "well above anything we've ever seen in the last 11,000 years."
That could be a rise of 2 to 11.5 degrees Fahrenheit, according to the NSF."
"The main culprit is carbon dioxide, and its levels have jumped in the last 100 years, Marcott said. In the 11,000 years prior, it only changed "very slowly," he said.
The last time Earth has been as warm as it is projected to be by 2100 was before the last Ice Age started -- over 130,000 years ago. That's too long ago to gather reliable data on, he said."
Global warming is epic, long-term study says - CNN.com