People, Environment

Why is Eastern North America Colder?

Why is Eastern North America Colder?
Why is Eastern North America Colder?

Why is Eastern North America so cold while the rest of the globe is getting warmer?

Temperatures across the Great Lakes and Eastern United States are setting cold temperature records for the first half of February, 2015, according to the Northeast Regional Climate Center.  Compared to expected temperatures, it is the coldest region of the planet.

Western North America, Europe, Asia, Australia, Africa and the Arctic are all much warmer right now than their historical mean temperatures for this time of year.

According to Climate Change Department of Cornell University, this pattern of a uniquely cold northeastern America has held throughout the last two winters. 

While “global warming” is clear in the map of temperature records across the globe, overall “climate change” is more subtle.  Some regions may experience more warming than others and some locations might even experience cooling for a while, while the overall globe warms.

Such differential effects can result if the total global temperature rise actually changes the patterns of atmospheric circulation and ocean temperatures and currents.

Are the last couple of cold winters in Eastern North America actually a feature of the overall warming, driven by changes in atmospheric circulation? Many in the Northeast would like to know, because that would tell if more such winters are to come in the decades ahead. The answer is not yet clear.

Some climate scientists have hypothesized that the warming Arctic and the loss of Arctic Sea ice lasting through the summer is changing the behavior of the jet stream in a way that contributes to both the heat waves and drought in the western half of the North America and the Arctic breakouts of cold air afflicting the eastern half. 

This is still a very controversial issue, however, and other climate scientists think that these regional patterns are just normal annual variation, albeit against a background of overall warming.

The question of how climate change is changing the likelihood of these interconnected regional weather contrasts is an extremely active field where more is known every day, but a definite answer on whether this Eastern cold spell is directly related to climate change is not yet known for certain.