Tag Archives: Global Warming

Increasing Heat Island Effect’s Influence on Urban Temperature Records Introduces Bias in Climate Studies

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When it comes to human-caused climate change, urban warming is a big player.

Sourced through Scoop.it from: www.cato.org

>”Perhaps no other climatic variable receives more attention in the debate over CO2-induced global warming than temperature. Its forecast change over time in response to rising atmospheric CO2 concentrations is the typical measure by which climate models are compared. It is also the standard by which the climate model projections tend to be judged; right or wrong, the correctness of global warming theory is most often adjudicated by comparing model projections of temperature against real-world measurements. And in such comparisons, it is critical to have a proper baseline of good data; but that is easier acknowledged than accomplished, as multiple problems and potential inaccuracies have been identified in even the best of temperature data sets.

One particular issue in this regard is the urban heat island effect, a phenomenon by which urban structures artificially warm background air temperatures above what they normally would be in a non-urbanized environment. The urban influence on a given station’s temperature record can be quite profound. In large cities, for example, urban-induced heating can be as great as Tokyo’s 10°C, making it all the more difficult to detect and discern a CO2-induced global warming signal in the temperature record, especially since the putative warming of non-urbanized areas of the planet over the past century is believed to be less than 1°C.  Yet, because nearly all long-term temperature records have been obtained from sensors initially located in towns and cities that have experienced significant growth over the past century, it is extremely important that urbanization-induced warming – which can be a full order of magnitude greater than the background trend being sought – be removed from the original temperature records when attempting to accurately assess the true warming (or cooling!) of the natural non-urban environment. A new study by Founda et al. (2015) suggests this may not be so simple or straightforward a task.

Working with temperature records in and around the metropolitan area of Athens, Greece, Founda et al. set out to examine the interdecadal variability of the urban heat island (UHI) effect, since “few studies focus on the temporal variability of UHI intensity over long periods.” Yet, as they note, “knowledge of the temporal variability and trends of UHI intensity is very important in climate change studies, since [the] urban effect has an additive effect on long term air temperature trends.”

[…]

Such findings as these are of significant relevance in climate change studies, for they clearly indicate the UHI influence on a temperature record is not static. It changes over time and is likely inducing an ever-increasing warming bias on the temperature record, a bias that will only increase as the world’s population continues to urbanize in the years and decades ahead. Consequently, unless researchers routinely identify and remove this growing UHI influence from the various temperature data bases used in global change studies, there will likely be a progressive overestimation of the influence of the radiative effects of rising CO2 on the temperature record. “<

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LA’s Urban Heat Island Effect Alters Weather

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Over the last 60 years urban areas of Southern California have lost significant amounts of fog due to the heat created by paved roads and buildings.

Source: www.scpr.org

>” A new study reports that coastal fog in Southern California is on the decline, especially in heavily urbanized areas.

In particular, Los Angeles saw a 63 percent decrease over the last 60 years.

You can blame the heat island effect created by city streets and buildings, said the study’s author Park Williams of Columbia University’s Lamont-Doherty Earth Observatory in New York.

Fog may be a nuisance for drivers, but according to Williams, it also plays a crucial role in hydrating many costal ecosystems.

These include mountains with coastal forests and hillsides covered in chaparral, which easily burns when conditions are too dry.

“They all receive water directly from fog and benefit from the shading of these clouds,” Williams said.

In fact, he noted that in some parts of Southern California, fog may provide plants with almost as much water as rain does. Williams says this loss of coastal fog could impact the regional environment.

Fog typically forms when the air is cool enough for clouds to condense close to ground level. This often happens at night and in the early morning.

However, Williams said this process is being upset by all the concrete in urban areas, which absorbs heat in the day and slowly releases it over night, raising temperatures.

“When you increase the temperature of the surface of the Earth, then you essentially need to go higher up into the atmosphere before [it] is cool enough to promote condensation,” Williams explained.

The end result is that as cities heat up, clouds rise and fog disappears.

Data for the study came from the detailed logs of the 24 coastal airports between Santa Barbara and San Diego.

“Of course airports have been collecting really good data on clouds because the presence of clouds and their hight in the atmosphere really affects air travel,” he said.

Many of these logs had hourly updates on cloud height, some dating back to the 1940s.

Using this information, Williams and his colleagues determined that the greatest loss of fog occurred in Ontario where there was a nearly 90% decrease over the last 60 years.

Other airports such as LAX, Burbank’s Bob Hope, Long Beach Airport and John Wayne Airport in Orange County also saw a considerable decrease in the average amount of fog.

However, less urban areas like Santa Barbara and the undeveloped the Channel Islands remained quite misty.

Williams says this trend is concerning because man-made climate change is expected to heat things up even more in the future.

Coastal fog can help cool an area down but as cities continue to bake, they will gather and emit even more heat, driving away even more fog.

“That can then feedback until the cloud layer is eaten away entirely in the daytime,” he said.

Soon, Williams hopes to explore how much water fog provides Southern California in general to see whether the continued loss of these low clouds could dry out the region even more.

His current paper appears in the journal Geophysical Research Letters.”<

 

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Climate Change, Pole Shift & Solar Weather

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Scientists tell us that our magnetic poles have reversed in the past, and that they will again. The last one occurred 780,000 years ago. The average time period between reversals is 450,000 years, but there isn’t really any pattern, it is random. We are overdue by average only.

Source: poleshift.com

>” […] Accelerating

This is indisputable – the speed at which the magnetic north pole is moving (not necessarily in the same direction) has recently become much faster. Because this is the entirety of our studies, we don’t know what was normal prior to the 1500s… […]

Not only are the poles moving rapidly – the strength of our magnetic field is diminishing as well:

Rapid changes in the churning movement of Earth’s liquid outer core are weakening the magnetic field in some regions of the planet’s surface, a new study says.

“What is so surprising is that rapid, almost sudden, changes take place in the Earth’s magnetic field,” said study co-author Nils Olsen, a geophysicist at the Danish National Space Center in Copenhagen.

…The changes “may suggest the possibility of an upcoming reversal of the geomagnetic field,” said study co-author Mioara Mandea, a scientist at the German Research Centre for Geosciences in Potsdam. [National Geographic]

[…] Possible Triggers

Scientists have not yet worked out what causes a magnetic reversal, but recent studies of Mercury suggest that the solar wind and particles from the Sun have an effect on planetary cores. My interpretation is that a massive solar storm could be thestraw that breaks the camel’s back and trigger a reversal if the Earth is ready for one. The Electric Universe folk have also suggested that a highly-charged comet passing by could also do the trick. Or perhaps ocean currents, after being affected by climate change, are the trigger? And if climate change is caused by the Sun, then that ties in nicely with the first theory.

Another theory comes from  Rich Muller:

where “lighter components, like oxygen, sulfur, and silicon . . . rise toward the core-mantle boundary (CMB).” Accumulating like sediment on the floor of the ocean, these “fall” upward from the core onto the surface of the mantle, which is uneven like the topography of the Earth’s surface. When enough sediment collects, it tumbles like an avalanche, into the outer core, thereby cooling it.

Rare events could trigger really big avalanches at the CMB, however. When a massive asteroid or comet slammed into Earth’s surface at an oblique angle, the lower mantle would jerk sideways, shearing off whole mountains of sediment. As the sediments slide up, a downward-sinking mass of cool iron could completely disrupt large convection cells. Although variously oriented local fields within the core would remain strong, at the surface Earth’s dipole magnetic field would collapse.

And according to Gary Glatzmaier reversals are rooted in chaos theory:

The resulting three-dimensional numerical simulation of the geodynamo, run on parallel supercomputers at the Pittsburgh Supercomputing Center and the Los Alamos National Laboratory, now spans more than 300,000 years.

Our solution shows how convection in the fluid outer core is continually trying to reverse the field but that the solid inner core inhibits magnetic reversals because the field in the inner core can only change on the much longer time scale of diffusion. Only once in many attempts is a reversal successful, which is probably the reason why the times between reversals of the Earth’s field are long and randomly distributed.

[…]”<

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Lord Lawson declares UK’s climate model ‘flawed’

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Lord Lawson is calling for an independent review of the UK’s official climate predictions as he claims the model used to make the projections is “flawed”. Based on research published …

Duane Tilden‘s insight:

>The thinktank claims predictions made by it will “always produce high estimates of future warming” regardless of the data fed into the process.

The HadCM3 model is used for official UK Climate Projections (UKCP09), which provide information to help plan how to adapt to a changing climate. It generates a virtual representation of the global climate such as the greenhouse effect, evaporation of the oceans, rainfall and sunlight. By increasing the greenhouse gases in the model, predictions on how much warmer the planet will become in the future can be made.

The UK’s climate model is also used to help make investment decisions across the public and private sectors and as estimates of future warming generated by the Government’s model are “much higher than those implied by several recent studies”, they are likely to “lead to considerable malinvestments” of public and private funds, GWPF claims.

Andrew Montford, author of the GWPF briefing paper said: “There are potentially billions of pounds being misspent on the basis of these predictions. The Government has little choice but to withdraw them pending a review of the way they are put together.”

The Met Office defended its methods and rubbished the criticism.

The organisation said in a statement: “UKCP09 used a sophisticated method that used both model projections and observations to provide a range of potential future warming which attempts to take in the uncertainties in model parameters. The GWPF article fails to note that UKCP09 also used information from many other climate models and that the projections were independently reviewed prior to publication.”<

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Global Warming – Paused or Peaked? – draft U.N. report

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OSLO (Reuters) – A “hiatus” in global warming so far this century is partly caused by natural variations in a chaotic climate and is unlikely to last, a draft United Nations report by leading climate scientists says.

Duane Tilden‘s insight:

>The fact that temperatures have risen more slowly in the past 15 years despite rising emissions of greenhouse gases has emboldened sceptics who challenge the evidence for man-made climate change and question the need for urgent action.

But the IPCC draft reports do not project any long-term respite. Instead, they forecast a resumption in the warming trend that is likely to cause ever more heatwaves, droughts, floods and rising sea levels. […]

“There are a number of explanations (for the hiatus), any one of which might be correct,” said professor Myles Allen of Oxford University, who contributed to the IPCC draft. “That is very different from saying:’We have no idea what’s going on’.”

The drafts say that a reduction in warming for 1998-2012 compared to 1951-2012 is “due in roughly equal measure” to natural variations in the climate and factors such as “volcanic eruptions and the downward phase of the current solar cycle.”<

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