Urban Heat Islands Hot and Getting Hotter

Published August 25, 2014

Climate Change Weekly #136

A new report by Climate Central, an online climate science and news organization, analyzing data from the 60 biggest cities in the United States found the urban heat island effect is big and getting bigger.

Most cities have seen dramatic growth over the past century. Eighty percent of Americans now live in cities. Unfortunately, this growth has exacerbated the urban heat island effect. Concrete and asphalt surfaces in city buildings, roads, and infrastructure hold more heat and release that heat more slowly than vegetation and organic surfaces, which is called the urban heat island (UHI) effect. As a result, urban areas are heating up faster than rural areas, and the temperature gap between the two is widening.

The study found:

  • Over the past 10 years, 57 of the 60 cities analyzed had measurable urban heat island effects with single-day urban temperatures as much as 27°F higher than surrounding rural areas.
  • Twenty-three cities experienced single days that were an as much as 20°F warmer than the rural areas around them.
  • Cities also have many more searing hot days each year. Twelve cities averaged at least 20 more days a year above 90°F than nearby rural areas since 2004.
  • Compared to the rural areas adjacent to them, the 60 cities analyzed averaged at least eight more days over 90°F each summer.

A number of studies have argued urban heat islands do not bias global warming measurements, therefore claiming rising temperatures cannot be due to urbanization alone. The Climate Central study shows the UHI is significantly greater than previously measured. And this is just in the United States. Cities in developing countries such as Brazil, China, India, and in the Middle East and Africa have grown much more rapidly over the past two decades, with a huge migration of peoples from rural to urban areas. No scientist can seriously believe these geographic and demographic changes have no effect on global temperature measurements.

SOURCE: Watts Up With That


New link found between the sun and climate … Sunspot cycles may indicate imminent global cooling … If global warming causes extinctions, where are the bodies? … Poll shows people aren’t concerned about global warming … Global warming is not increasing hunger


A new study published in Nature: Geoscience “… shows an unexpected link between solar activity and climate change,” said coauthor Dr. Raimund Muscheler. Using reconstructions of solar activity and snowfall accumulation, the study found changes in solar activity are nothing new and that the changes affect climate, especially on the regional level. Although Muscheler personally asserts current warming is not due primarily to the sun, he said climate modelers should take better account of solar activity when developing and running their models.

SOURCE: What’s Up With That


New data and revisions to the historic sunspot record indicate Earth could be in for a cold spell. The Royal Observatory of Belgium plans the first revision of the 400-year sunspot record since it was established in 1849 by Rudolf Wolf. Those revisions will affect long-term scientific studies dependent on sunspot data, including climate studies. The new record will make the current sunspot cycle, Cycle 24, the weakest in 200 years. Long-term indicators suggest the next sunspot cycle will be significantly weaker than the current one, and if history holds true this could portend a general cooling trend for the planet.

SOURCE: The Observatory


Rud Istvan, a guest writer on climate scientists’ Judith Curry’s popular Climate etc. website, points out several shortcomings in arguments that global warming is likely to cause mass extinctions. The United Nations Intergovernmental Panel on Climate Change (IPCC) has projected 21% to 52% of all species would be on the road to extinction with a warming of 3°C above preindustrial levels, absent mitigation. There are at least two serious flaws behind this claim, Istvan notes. First, history shows many significant climate shifts have resulted in few extinctions. Second, although the IPCC cites 57 peer-reviewed papers when discussing biodiversity, the global extinction rate estimate comes from just one paper, and this paper’s estimates are based on dubious computer models. As one analysis put it, the IPCC used selection bias to promote the flawed estimates of a single paper, which had been highly criticized in multiple peer-reviewed papers.

SOURCE: Climate etc.


A new survey conducted for the Pittsburgh Post-Gazette finds people are not very concerned about global warming. Among the conclusions: (1) many Americans remain uncertain about the impact of climate change; (2) Americans are even less convinced of the need for government action to address climate change; and (3) many polls that show higher support for government action are flawed by faulty methodology and/or biased wording. The survey found, “Just 41 percent of Americans are confident that ‘most scientists agree that climate change is happening now caused mainly by human activities,’ while 18 percent firmly believe ‘there is little agreement among scientists’ on the issue and the rest are unsure.'”

SOURCE: Pittsburgh Post-Gazette


The United Nations’ Food and Agriculture Organization (FAO) reports the number of undernourished people in the world is declining. Contrary to the IPCC’s misleading claims that the number of undernourished people increased by 75 million since 2003, the most recent FAO report shows the number of undernourished fell 17 percent in developed countries and globally. The IPCC got its inaccurate figure from an outdated monograph which that older, uncorrected FAO data. After a thorough reassessment of its procedures, the FAO revised its undernourishment numbers.

SOURCE: Climate Audit

The Climate Change Weekly Newsletter has been moved to HeartlandDailyNews.com. Please check there for future updates!