Posted on June 9, 2012 by Bob Berwyn
New study suggests that Earths climate has evolved to become more sensitive to greenhouse gases
A slightly different alignment continents during the Miocene Era may have been a big factor in sustaining warmer global temperatures with relatively low levels of CO2.
By Summit Voice
SUMMIT COUNTY — The modern era’s link between atmospheric carbon dioxide levels and temperatures is nearly undisputed as both have climbed in tandem during recent decades.
But new studies of fossilized plankton suggests there was a time in the Earth’s history, about 12 million to 5 million years ago, when the climate warmed without a corresponding increase in atmospheric CO2, perhaps because of vastly different circulation patterns in the world’s oceans.
The scientists, led by Jonathan LaRiviere and Christina Ravelo of the University of California at Santa Cruz, reconstructed an open-ocean Pacific temperature record during the late Miocene epoch, finding that temperatures across a broad swath of the North Pacific were 9-14 degrees Fahrenheit warmer than today, while atmospheric carbon dioxide concentrations remained low–near values prior to the Industrial Revolution. (more…)
Filed under: climate and weather, Environment, global warming | Tagged: Carbon dioxide in Earth's atmosphere, Central American Seaway, climate, global warming, Miocene, Pacific Ocean | 11 Comments »
Posted on December 27, 2011 by Bob Berwyn
Does a changing climate spur evolutionary leaps?
Six waves of change likely tied to shift in the planet's environment.
By Summit Voice
SUMMIT COUNTY — With some intensive scientific sleuthing that spanned millions of years, scientists say they’ve been able to link changes in species diversity with changing climate.
The research shows six distinct, consecutive waves of mammal species diversity, or “evolutionary faunas,” likely tied to major shifts in the planet’s environment.
“Although we’ve always known in a general way that mammals respond to climatic change over time, there has been controversy as to whether this can be demonstrated in a quantitative fashion,” said Brown University evolutionary biology Professor Christine Janis. “We show that the rise and fall of these faunas is indeed correlated with climatic change – the rise or fall of global paleotemperatures – and also influenced by other more local perturbations such as immigration events.” (more…)
Filed under: biodiversity, climate and weather, Summit County news | Tagged: Brown University, climate change, Environment, Miocene | 1 Comment »