CO2 Science links to this study. Climate catastrophists bend over backwards to try to argue that there are no such thing as urban heat islands. But of course, whenever anyone gathers actual data rather than trying to use goofy computer model approaches, the answer is always the same:
To assess the validity of this assumption, LaDochy et al. "use temperature trends in California climate records over the last 50 years [1950-2000] to measure the extent of warming in the various sub-regions of the state." Then, "by looking at human-induced changes to the landscape, [they] attempt to evaluate the importance of these changes with regard to temperature trends, and determine their significance in comparison to those caused by changes in atmospheric composition," such as atmospheric CO2 concentration….
The three researchers found that "most regions showed a stronger increase in minimum temperatures than with mean and maximum temperatures," and that "areas of intensive urbanization showed the largest positive trends, while rural, non-agricultural regions showed the least warming." In fact, they report that the Northeast Interior Basins of the state actually experienced cooling. Large urban sites, on the other hand, exhibited rates of warming "over twice those for the state, for the mean maximum temperatures, and over five times the state’s mean rate for the minimum temperature."
I would have thought the following conclusion would have been a blinding glimpse of the obvious, but I guess it still needs to be said over and over:
LaDochy et al. write that "if we assume that global warming affects all regions of the state, then the small increases seen in rural stations can be an estimate of this general warming pattern over land," which implies that "larger increases," such as those found in areas of intensive urbanization, "must then be due to local or regional surface changes."
Not only is it blindingly obvious that the Urban Heat Island effect is responsible for recording higher minimum temperatures, it is also responsible for many weather stations that were previously well sited to become mini-urban heat islands as parking lots and buildings and air-conditioners encroach on those sites and significantly skew the temperatures being recorded… both higher lows and higher highs… and, presto, global warming!
“Heat islands” are tough to explain if you’re measuring greenhouse effects (unless you belive the wind doesn’t mix urban vs. rural air). It’s more likely, I suspect, that we’re seeing a good deal of *direct* heating from all kinds of urban combustion–heating, electrical generation, car engines, etc. Virtually all of the fuel that comes into a modern city is turned into BTUs that directly warm the local environment (a “campfire effect”?). In fact, even nuclear plants generate huge amounts of heat, which is dissapated through cooling towers or just pumped into local rivers.
Again, blindingly obvious: Fire is hot.
For some reason…whenever you talk of “heat islands”…the Atlanta region is always the best example that folks use. There is no doubt…with the massive cutting of trees over the past fifty years and massive use of asphalt and concrete…we’ve doubled-up the heat production of Atlanta and its 50-mile radius. I’d like to see a 20-year project where we plant a massive amount of trees in the region (state, private and nationally-funded)…to make the point that we could cool a “heat island”, if we really wanted to. The question comes up though…even if we cooled Atlanta by an average of four degrees over an entire summer…are we really accomplishing anything of real value…other than personal comfort?
For some reason…whenever you talk of “heat islands”…the Atlanta region is always the best example that folks use. There is no doubt…with the massive cutting of trees over the past fifty years and massive use of asphalt and concrete…we’ve doubled-up the heat production of Atlanta and its 50-mile radius. I’d like to see a 20-year project where we plant a massive amount of trees in the region (state, private and nationally-funded)…to make the point that we could cool a “heat island”, if we really wanted to. The question comes up though…even if we cooled Atlanta by an average of four degrees over an entire summer…are we really accomplishing anything of real value…other than personal comfort?
For some reason…whenever you talk of “heat islands”…the Atlanta region is always the best example that folks use. There is no doubt…with the massive cutting of trees over the past fifty years and massive use of asphalt and concrete…we’ve doubled-up the heat production of Atlanta and its 50-mile radius. I’d like to see a 20-year project where we plant a massive amount of trees in the region (state, private and nationally-funded)…to make the point that we could cool a “heat island”, if we really wanted to. The question comes up though…even if we cooled Atlanta by an average of four degrees over an entire summer…are we really accomplishing anything of real value…other than personal comfort?
JT,
while there is the direct impact of being in the vicinity of heat producers, there is also the stored/augmented heat from concrete structures and asphalt paving, among others, that affect the urban [heat island] area but dissipate quickly beyond [certainly some mixing occurs, but heated air also rises and cools].
Perhaps you’ve heard the urban weather station expression, “Low tonight in the XXs; cooler in the outlying areas.” There’s a reason for that.
The heat island effect is a strong distortion of surface temperature readings. The effect on satellite readings should be minimal and easily corrected. Wherever climate models use surface temperatures as parameters, they are skewed.
CO2 is a minimal, self-limiting forcing. Much stronger anthropogenic forcings include land use changes. The non-anthropogenic forcings blow everything else out of the water.