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Despite having little impact on global mean temperatures, waste heat may alter weather significantly

A diverse team of researchers from Scripps Institution of OceanographyUniversity of California, San Diego (UCSD); Florida State University (FSU); and the National Center for Atmospheric Research (NCAR) have teamed up to examine the long term effects of waste heat on local surroundings.

I. Waste Heat Shifts Temperature Balance

Urban heat originates from a variety of sources -- buildings with central heating, power plants, cars, and more.  Human machines dump waste heat into the environment on a large scale locally.  But globally waste heat is only estimated to account for around 0.3 percent of the total heat transported across higher latitudes by atmospheric or oceanic circulation, bumping temperatures by a mere 0.01 degrees C (about 0.02 degrees F).

The "urban heat island" effect -- local warming from waste heat -- is well known.  But the research team suspected that waste heat might have longer-range effects too, effects that might be masked by the global trend.  They dug into the issue and developed models that suggest that waste may indeed have longer-range impact, in addition to the urban heat island effect.

The new, more detailed smaller-scale models show that waste heat from cities may heat up northern regions of North America and Asia by as much as 1 degree Celsius (1.8 degrees Fahrenheit) in the winter.  The heating effects can be felt up to 1,000 miles away from their source, the simulations showed.  At the same time, the North American/Asian heating is coupled with a 1 degree Celsius (1.8 degrees Fahrenheit) cooling effect in Europe, which is forcing cooler winters.

Waste Heat
Waste heat is warming North America and Asia's north, while cooling the European north.
[Image Source: Ecofriend]

NCAR researcher Aixie Hu comments, "The burning of fossil fuel not only emits greenhouse gases but also directly affects temperatures because of heat that escapes from sources like buildings and cars.  Although much of this waste heat is concentrated in large cities, it can change atmospheric patterns in a way that raises or lowers temperatures across considerable distances."

II. What Can be Done?

Humans by and large produce much less waste heat than nature (respiration itself, the process by which living organisms harvest energetic chemicals to drive the processes of life, puts off a fair deal of waste heat).  But many human cities happen to be located directly under jet stream troughs, which causes the localized impact to be amplified.

Globally in 2006 energy consumption globally was estimated to have occurred at an average of 16 terawatts (TW).  The 86 largest metropolitan areas in the Northern Hemisphere are estimated to have consumed 6.7 TW of that total.

Urban heat map
U.S. urban centers often sit under jet stream troughs. [Image Source: Blue Moon/Panoramio]

The study is arguably less about prevention, and more about understanding and coping with mankind's localized impact on weather/climate.  After all, you can't reasonably ask people to turn off the heat in the winter or stop driving (even EVs put off waste heat).

But perhaps future urban expansion can be guided by models that place new construction in areas that suck less of the waste heat into the jet stream or alternatively suck up more in regions that are currently being cooled.

Additionally materials may be able to recapture some waste heat, decreasing the global output, while at the same time lowering costs. (But such materials are still in their very nascent stages.)

The study was published in the peer-reviewed journal Nature Climate Change.

Sources: UCAR [press release], Nature Climate Change [abstract]



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RE: I suggested this
By DrizztVD on 1/28/2013 2:47:54 PM , Rating: 2
The problem with climate change and in particular global warming up to this point, is not that humans have some effect on the environment but rather how large that effect is. While there are many engines releasing heat into the atmosphere, this is not even a drop in the ocean compared to the amount of heat the sun dumps on earth every day.

This is why you will find that the researchers propose a type of 'heat exchange' effect, where a miniscule influence on one part of the thermal system propagates to global climate shifts. This reminds of the theory that says the flap of a butterfly's wings can influence the weather on the other side of the planet. You can make such a statement and even give evidence to support it, but it really is of no practical use because there are just too many small influences to keep track of.

I really think that the challenge for the next generation will be to get everyone off fossil fuel dependance. Other than that worrying about global climate shifts (or catastrophes) really won't help if we don't actually have any means to prevent it even if we knew it was coming.


RE: I suggested this
By Mint on 1/28/2013 4:05:24 PM , Rating: 1
Relatively speaking, I think the estimates of how much warming is happening is pretty decent. Even a factor of 2 is good enough.

The real problem with AGW is quantifying how much damage it causes, and whether it's worth addressing. Using the IPCC's own warming numbers, the ~$0.05/kWh premium paid for wind via feed-in-tariffs around the world is equivalent paying about $1 trillion to prevent 0.01 deg of warming. I'm pretty sure we could solve world hunger for the cost of preventing 0.1 deg of warming. It's downright immoral to do the latter while claiming that we can't afford the former.

The development of India, China, and hopefully Africa to the point where they emit even half the CO2 per capita that we do means that even if the IPCC is right, warming is going to happen, period.

Adaptation is a much more sensible option than prevention.


RE: I suggested this
By tng on 1/29/2013 9:55:13 AM , Rating: 2
quote:
The problem with climate change and in particular global warming up to this point, is not that humans have some effect on the environment but rather how large that effect is.
Exactly
quote:
...this is not even a drop in the ocean compared to the amount of heat the sun dumps on earth every day.

So true, yet there are scientists out there that have made connections between global warming and solar cycles and have been called nutcases or worse by the IPCC, simply because it may not fit what with the IPCC says.

I think that GW is real, but I am convinced that the IPCC is a bid for more money and control.


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