heat waves

Most US maximum temperature records set in the 1930s

Global warming is a funny thing. Whenever we experience a heat wave the press proclaims it is the face of global warming, but when we have an unusual cold snap, it is merely natural variation.

The Arizona Daily Star had an interesting article today concerning the number of days in Tucson with maximum temperatures over 100° F. The story says the record was set in 1994 with 99 days over 100° F and speculates upon our chances of breaking that record this year. The “normal” number of days over 100° F is 62 according to the National Weather Service.

Also interesting is the statistic that July 4, 2012, had the coolest maximum temperature on record, 86°F.

Looking at a larger picture and a slightly different statistic, we see that the greatest number of maximum temperature records in the U.S. were set in the 1930s. Below is a graph compiled by Steven Goddard from U.S. Historical Climatology Network (USHCN) records:


Getting back to Tucson, we see from the graphics in the Star article that we have had more years, with more days over 100° F than “normal” within the last 25 years or so. That could be a reflection of the urban heat island effect. Our asphalt and concrete absorbs more heat and reflects it back at night. I discuss that in my post Warmer nights no proof of global warming.

A graphic from that post demonstrates the problem by comparing the temperature trend in urban Tucson with that from rural Tombstone:

Tucson-Tombstone temp

You can see that Tucson temperatures have been rising but there is no trend in the rural Tombstone station. Carbon dioxide works in mysterious ways.

So, the big news from the Arizona Daily Star is: Summers in Tucson are hot.

See also:

Human induced warming in Tucson

IPCC says they don’t know if the climate is becoming more extreme

There has been much speculation and many headlines about the relationship between global warming and extreme weather.  For example, see this recent alarmist story from the AP in the Arizona Daily Star: “World warned to prepare for extreme weather.”  The first line of that story says, “Global warming is leading to such severe storms, droughts and heat waves that nations should prepare for an unprecedented onslaught of deadly and costly weather disasters, an international panel of climate scientists said in a new report issued Wednesday.”  Apparently the story authors got their information from alarmist press releases and interviews rather than the report itself.  (They got the page count wrong too.)

The basic conclusion of the Intergovernmental Panel on Climate Change’s (IPCC) new report on the subject of extreme weather is: “While there is evidence that increases in greenhouse gases have likely caused changes in some types of extremes, there is no simple answer to the question of whether the climate, in general, has become more or less extreme.”

While storm damage makes the news, the damage is largely an artifact of our propensity for building infrastructure in the areas subject to extreme weather rather than any imagined increase in such weather.

IPCC: “There is medium evidence and high agreement that long-term trends in normalized losses have not been attributed to natural or anthropogenic climate change.”

Some other interesting quotes from the IPCC report:

“The statement about the absence of trends in impacts attributable to natural or anthropogenic climate change holds for tropical and extratropical storms and tornados.”

“The absence of an attributable climate change signal in losses also holds for flood losses.”

“Some authors suggest that a (natural or anthropogenic) climate change signal can be found in the records of disaster losses (e.g., Mills, 2005; Höppe and Grimm, 2009), but their work is in the nature of reviews and commentary rather than empirical research.”

You can download the 582-page report here: http://www.ipcc-wg2.gov/SREX/  That page allows you to download either the Summary for Policy Makers (11.8 Mb) or the full report (44 Mb).

See also:

The Storm Over Tornadoes

Media pawns in IPCC extreme weather hype

Pained Earth’s summer to forget: the rest of the story

Weather extremes not increasing with warming

Extreme weather makes news.  It is a tenet of catastrophic anthropogenic global warming adherents (CAGWs) that extreme weather events have become and will become ever more common as the planet warms.  However, new research in Europe, based on historical records and tree-rings, covering the period AD 962–2007, shows no trend in extreme weather events. In fact, the researchers found “A fairly uniform distribution of hydroclimatic extremes throughout the Medieval Climate Anomaly, Little Ice Age and Recent Global Warming…”

 The paper is Buntgen, U.et al., 2011. Combined dendro-documentary evidence of Central European hydroclimatic springtime extremes over the last millennium. Quaternary Science Reviews 30: 3947-3959..(Link to abstract, the full paper is behind a pay wall.)

The abstract reads:

A predicted rise in anthropogenic greenhouse gas emissions and associated effects on the Earth’s climate system likely imply more frequent and severe weather extremes with alternations in hydroclimatic parameters expected to be most critical for ecosystem functioning, agricultural yield, and human health. Evaluating the return period and amplitude of modern climatic extremes in light of pre-industrial natural changes is, however, limited by generally too short instrumental meteorological observations. Here we introduce and analyze 11,873 annually resolved and absolutely dated ring width measurement series from living and historical fir (Abies alba Mill.) trees sampled across France, Switzerland, Germany, and the Czech Republic, which continuously span the AD 962–2007 period. Even though a dominant climatic driver of European fir growth was not found, ring width extremes were evidently triggered by anomalous variations in Central European April–June precipitation. Wet conditions were associated with dynamic low-pressure cells, whereas continental-scale droughts coincided with persistent high-pressure between 35 and 55°N. Documentary evidence independently confirms many of the dendro signals over the past millennium, and further provides insight on causes and consequences of ambient weather conditions related to the reconstructed extremes. A fairly uniform distribution of hydroclimatic extremes throughout the Medieval Climate Anomaly, Little Ice Age and Recent Global Warming may question the common believe that frequency and severity of such events closely relates to climate mean stages. This joint dendro-documentary approach not only allows extreme climate conditions of the industrial era to be placed against the backdrop of natural variations, but also probably helps to constrain climate model simulations over exceptional long timescales.

In a previous post, Media pawns in IPCC extreme weather hype, I present research and graphics that show there have been no upward trends in droughts, wet weather, or hurricanes as the world warmed from the “little ice age.”

In spite of science to the contrary, CAGWs and the IPCC must continue to present their scary stories to secure funding to fight their imagined hobgoblins and gain power.  And such stories sell newspapers.

See also:

Pained Earth’s summer to forget: the rest of the story

Book Review: The Delinquent Teenager Who Was Mistaken for the World’s Top Climate Expert, an IPCC Exposé