Scientists: We were headed for an ice age, but greenhouse gases will almost certainly prevent that, and that's allegedly bad

Global Temperatures Highest in 4,000 Years, Study Says - NYTimes.com

Michael E. Mann, a researcher at Pennsylvania State University who is an expert in the relevant techniques but was not involved in the new research, said the authors had made conservative data choices in their analysis.
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Scientists say that if natural factors were still governing the climate, the Northern Hemisphere would probably be destined to freeze over again in several thousand years. “We were on this downward slope, presumably going back toward another ice age,” Dr. Marcott said.

Instead, scientists believe the enormous increase in greenhouse gases caused by industrialization will almost certainly prevent that.
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Dr. Mann pointed out that the early Holocene temperature increase was almost certainly slow, giving plants and creatures time to adjust. But he said the modern spike would probably threaten the survival of many species, in addition to putting severe stresses on human civilization.

“We and other living things can adapt to slower changes,” Dr. Mann said. “It’s the unprecedented speed with which we’re changing the climate that is so worrisome.”