Dr. Roy Spencer recently opined about this issue (which is different from UHI) in: Waste Heat as a Contributor to Observed Warming
If we divide that by the surface area of the U.S. in meters, we get 0.33 watts per sq. meter.
Now, compare that the the total radiative forcing from increasing greenhouse gas concentrations supposedly operating today, which (according to the IPCC) is somewhere around 1.6 W/m2.
…waste heat from our use of energy keeps getting generated, no matter how much our surroundings have warmed. So, with this correction, we now see that waste heat generation (0.33) becomes more like 50% of the remaining radiative imbalance (0.6) from anthropogenic GHG production.
Waste Heat is Mostly Released in the Lowest 10% of the Atmosphere
It seems his observations were spot-on, as this new paper just published in Nature Climate Change tells us. From the University of San Diego:
Urban Heat Has Large-scale Climate Effects
Researchers find that heat given off by metropolitan areas is enough to influence winter warming
The heat generated by everyday activities in metropolitan areas has a significant enough warming effect to influence the character of the jet stream and other major atmospheric systems during winter months, according to a trio of climate researchers.
Led by Guang Zhang, a research meteorologist at Scripps Institution of Oceanography, UC San Diego, the scientists report in the journal Nature Climate Change that the extra heat given off by Northern Hemisphere urban areas causes as much as 1 degree C (1.8 degrees F) of warming in winter. They added that this effect helps explain the disparity between actual observed warming in the last half-century and the amount of warming that computer models have been able to account for.
“What we found is that energy use from multiple urban areas collectively can warm the atmosphere remotely, thousands of miles away from the energy consumption regions,” said Zhang. “This is accomplished through atmospheric circulation change.”
The study, “Energy consumption and the unexplained winter warming over northern Asia and North America,” appears in online editions of the journal Jan. 27. The National Science Foundation, the U.S. Department of Energy, and NOAA supported the research.
Zhang, along with Ming Cai of Florida State University and Aixue Hu of the National Center for Atmospheric Research in Boulder, Colo., considered the energy consumption – from heating buildings to powering vehicles – that generates waste heat release. The world’s total energy consumption in 2006 was 16 terawatts (one terawatt equals 1 trillion watts). Of that, 6.7 TW were consumed in 86 metropolitan areas in the Northern Hemisphere.
The release of waste heat is different from energy that is naturally distributed in the atmosphere, the researchers noted. The largest source of heat, solar energy, warms Earth’s surface and atmospheric circulations distribute that energy from one region to another. Human energy consumption distributes energy that had lain dormant and sequestered for millions of years, mostly in the form of oil or coal. Though the amount of human-generated energy is a small portion of that transported by nature, it is highly concentrated in urban areas. In the Northern Hemisphere, many of those urban areas lie directly under major atmospheric troughs and jet streams.
Zhang said the effect his team studied is distinct from the so-called urban heat island effect, an increase in the warmth of cities compared to unpopulated areas caused by human activities.
The authors report that the influence of urban heat can widen the jet stream and strengthens atmospheric flows at mid-latitudes. They add that the warming is not uniform. Partially counterbalancing it, the changes in major atmospheric systems cool areas of Europe by as much as 1 degree C, with much of the temperature decrease occurring in the fall.
Overall, these changes have a noticeable but slight effect on global temperatures, increasing them worldwide by an average of about 0.1 degree C.
The study does not address whether the urban heating effect disrupts atmospheric weather patterns or plays a role in accelerating global warming, though Zhang said drawing power from renewable sources such as solar or wind provides a societal benefit in that it does not add net energy into the atmosphere.
The authors also contend that the urban heat effect accounts for the discrepancy between observed warming and winter warming simulated in the models used by the climate science community for analysis and prediction of climate. They suggest that the influence of energy consumption accompany heat-trapping gases and aerosols as necessary variables in computer models.
Here is another press release from NCAR:
BOULDER—Even if you live more than 1,000 miles from the nearest large city, it could be affecting your weather.
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.
However, the noticeable impact on regional temperatures may explain why some regions are experiencing more winter warming than projected by climate computer models, the researchers conclude. They suggest that models be adjusted to take the influence of waste heat into account.
“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,” says NCAR scientist Aixue Hu, a co-author of the study. “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.”
Distinct from urban heat island effect
The researchers stressed that the effect of waste heat is distinct from the so-called urban heat island effect. Such islands are mainly a function of the heat collected and re-radiated by pavement, buildings, and other urban features, whereas the new study examines the heat produced directly through transportation, heating and cooling units, and other activities.
The study, “Energy consumption and the unexplained winter warming over northern Asia and North America,” appeared online yesterday. It was funded by the National Science Foundation, NCAR’s sponsor, as well as the Department of Energy and the National Oceanic and Atmospheric Administration.
Hu, along with lead author Guang Zhang of Scripps and Ming Cai of Florida State University, analyzed the energy consumption—from heating buildings to powering vehicles—that generates waste heat release. The world’s total energy consumption in 2006 was equivalent to a constant-use rate of 16 terawatts (1 terawatt, or TW, equals 1 trillion watts). Of that, an average rate of 6.7 TW was consumed in 86 metropolitan areas in the Northern Hemisphere.
Using a computer model of the atmosphere, the authors found that the influence of this waste heat can widen the jet stream.
“What we found is that energy use from multiple urban areas collectively can warm the atmosphere remotely, thousands of miles away from the energy consumption regions,” Zhang says. “This is accomplished through atmospheric circulation change.”
The release of waste heat is different from energy that is naturally distributed in the atmosphere, the researchers noted. The largest source of heat, solar energy, warms Earth’s surface and atmospheric circulations redistribute that energy from one region to another. Human energy consumption distributes energy that had lain dormant and sequestered for millions of years, mostly in the form of oil or coal.
Though the amount of human-generated energy is a small portion of that transported by nature, it is highly concentrated in urban areas. In the Northern Hemisphere, many of those urban areas lie directly under major atmospheric troughs and jet streams.
“The world’s most populated and energy-intensive metropolitan areas are along the east and west coasts of the North American and Eurasian continents, underneath the most prominent atmospheric circulation troughs and ridges,” Cai says. “The release of this concentrated waste energy causes the noticeable interruption to the normal atmospheric circulation systems above, leading to remote surface temperature changes far away from the regions where waste heat is generated.”
About the article
Title: Energy consumption and the unexplained winter warming over northern Asia and North America
Authors: Ghang J. Zhang, Ming Cai, and Aixue Hu
Publication: Nature Climate Change, January 27, 2013
Energy consumption and the unexplained winter warming over northern Asia and North America
The worldwide energy consumption in 2006 was close to 498 exajoules. This is equivalent to an energy convergence of 15.8 TW into the populated regions, where energy is consumed and dissipated into the atmosphere as heat. Although energy consumption is sparsely distributed over the vast Earth surface and is only about 0.3% of the total energy transport to the extratropics by atmospheric and oceanic circulations, this anthropogenic heating could disrupt the normal atmospheric circulation pattern and produce a far-reaching effect on surface air temperature. We identify the plausible climate impacts of energy consumption using a global climate model. The results show that the inclusion of energy use at 86 model grid points where it exceeds 0.4 W m−2 can lead to remote surface temperature changes by as much as 1 K in mid- and high latitudes in winter and autumn over North America and Eurasia. These regions correspond well to areas with large differences in surface temperature trends between observations and global warming simulations forced by all natural and anthropogenic forcings1. We conclude that energy consumption is probably a missing forcing for the additional winter warming trends in observations.
The supplementary Information (SI) for this paper is here, and well worth reading:
I’ll have updates to this in follow up stories – Anthony