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Mon Jan 28, 2013, 06:29 AM

Heat from North American cities causing warmer winters, study finds

http://www.guardian.co.uk/science/2013/jan/27/scienceofclimatechange-climate-change


All those buildings and all those people in New York are generating heat thousands of miles away. Photograph: Matthew Lloyd/Getty Images


Those who wonder why large parts of North America seem to be skipping winter have a new answer in addition to climate change: big city life.

A study, published in the journal Nature Climate Change, found that the heat thrown off by major metropolitan areas on America's east coast caused winter warming across large areas of North America, thousands of miles away from those cities.

Winter warming was detected as far away as the Canadian prairies. In some remote areas, temperature rose by as much as 1 degree C (1.8F) under the influence of big cities, which produced changes in the jet stream and other atmospheric systems, the study found.

Researchers found a similar pattern in Asia, where major population centres resulted in strong warming in Russia, northern Asia, and eastern China.

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Response to xchrom (Original post)

Mon Jan 28, 2013, 08:43 AM

1. At the rate of City Kill by mass unemployment, this shouldn't be a problem much longer

Detroit, Cleveland, most of Pennsylvania, Camden, Newark....the metro areas are no more.

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Response to Demeter (Reply #1)

Mon Jan 28, 2013, 08:44 AM

2. +1

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Response to Demeter (Reply #1)

Fri Feb 1, 2013, 08:17 PM

7. Those metro areas are still large, almost all are growing --here's some data to counter your claims

Detroit, Cleveland, PA's large Metro areas (which include Camden, in the Philly Metro Area), and Newark, which is part of the New York City Metro area:

Since 1950:
the Detroit Metropolitan area population has grown 42%
the Cleveland Metropolitan area population has grown 29%
the Pittsburgh Metropolitan area population actually has declined by 9%
the Philadelphia Metropolitan area population has grown 61%
the New York City Metropolitan area population has grown 58%

Since 1980:
the Detroit Metropolitan area population has declined by 2%
the Cleveland Metropolitan area population has declined by 2%
the Pittsburgh Metropolitan area population has declined by 11%
the Philadelphia Metropolitan area population has grown 26%
the New York City Metropolitan area population has grown 30%

In other words, despite you saying these "metro" areas are no more, the Metropolitan areas that include the cities that you listed have mostly all grown since 1950, have mostly grown or slightly declined since 1980, AND, importantly, are still really large Metropolitan areas now.

Metropolitan Statistical Area Population estimate for 2011:
Detroit 4.285 million
Cleveland 2.871 million
Pittsburgh 2.359 million
Philadelphia 6.562 million
New York City 22.214 million


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Response to xchrom (Original post)

Thu Jan 31, 2013, 05:39 PM

3. Cities change temperatures for thousands of miles—(The net effect … global mean … nearly negligible)

http://www2.ucar.edu/atmosnews/news/8773/cities-affect-temperatures-thousands-miles
Cities change temperatures for thousands of miles

January 27, 2013



In a new study that shows the extent to which human activities are influencing the atmosphere, scientists have concluded that the heat generated by everyday activities in metropolitan areas alters the character of the jet stream and other major atmospheric systems. This affects temperatures across thousands of miles, significantly warming some areas and cooling others, according to the study this week in Nature Climate Change.

The extra “waste heat” generated from buildings, cars, and other sources in major Northern Hemisphere urban areas causes winter warming across large areas of northern North America and northern Asia. Temperatures in some remote areas increase by as much as 1 degree Celsius (1.8 degrees Fahrenheit), according to the research by scientists at the Scripps Institution of Oceanography; University of California, San Diego; Florida State University; and the National Center for Atmospheric Research.

At the same time, the changes to atmospheric circulation caused by the waste heat cool areas of Europe by as much as 1 degree C (1.8 degrees F), with much of the temperature decrease occurring in the fall.

The net effect on global mean temperatures is nearly negligible—an average increase worldwide of just 0.01 degrees C (about 0.02 degrees F). This is because the total human-produced waste heat is only about 0.3 percent of the heat transported across higher latitudes by atmospheric and oceanic circulations.

http://dx.doi.org/10.1038/nclimate1803

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Response to OKIsItJustMe (Reply #3)

Thu Jan 31, 2013, 06:48 PM

4. The net effect may not be able to be calculated by the global mean

 

Global mean is just a number. It doesn't actually tell you what the local effects are on the ground (or in the jetstream) from the warming near the cities (or how such effects could reverberate outwards).

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Response to NoOneMan (Reply #4)

Fri Feb 1, 2013, 11:04 AM

5. Just a meaningful number.

http://www2.ucar.edu/atmosnews/news/8773/cities-affect-temperatures-thousands-miles


The extra “waste heat” generated from buildings, cars, and other sources in major Northern Hemisphere urban areas causes winter warming across large areas of northern North America and northern Asia. Temperatures in some remote areas increase by as much as 1 degree Celsius (1.8 degrees Fahrenheit), according to the research by scientists at the Scripps Institution of Oceanography; University of California, San Diego; Florida State University; and the National Center for Atmospheric Research.

At the same time, the changes to atmospheric circulation caused by the waste heat cool areas of Europe by as much as 1 degree C (1.8 degrees F), with much of the temperature decrease occurring in the fall.



OK, so, are the cities warming or cooling the planet?

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Response to OKIsItJustMe (Reply #5)

Fri Feb 1, 2013, 12:22 PM

6. Either way, they are messing with the local ecosystems

 

The +/-1C changes are not zero sum, even if they average out globally. That could be the difference between some plants not going to seed at the right time, or some species having a food crisis. You know what I mean?

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