Temperature Anomalies

The sweltering July heat was reminiscent of a line from the Lovin' Spoonful tune Summer In The City:

All around, people looking half dead
Walking on the sidewalk, hotter than a match head

High temperatures fueled wildfires, warmed and dried up surface water, exacerbated drought conditions, and wilted crops around the globe.

July 2012 was the hottest month on record in the United States.

It ain't the heat; it's the humility.
~ Yogi Berra

July 2012 - Difference from mean historical temperature for July 1895-2012
NOAA National Climatic Data Center

The Antarctic Peninsula, much of eastern Europe, and North Africa also recorded unusually warm temperatures in July. To the contrary, Australia, Northern and Western Europe, Eastern Russia, Alaska, and Southern South America were cooler than normal.

A statistical trend towards climate extremes concerns climatologists.

The distribution of seasonal mean temperature anomalies has shifted toward higher temperatures and the range of anomalies has increased.
~ James Hansen, NASA GISS director

July 2012 Data (Source National Climatic Data Center)

• The average combined global land and ocean surface temperature was 1.12°F above the 20^th century average (60.4°F) for July.
• The Northern Hemisphere land surface temperature was the all-time warmest July on record since 1895, at 2.14°F above the average.
• Over 2 million acres burned in the United States due to wildfires (the fourth most since 2000).
• Moderate to exceptional drought conditions were recorded in 62.9 percent of the contiguous United States.
• It was the fourth consecutive month the Northern Hemisphere set a new monthly land temperature record.
• Sea ice in the Arctic averaged only 3.1 million square miles (the second lowest July sea ice extent on record).

Selected significant climate anomalies that occurred in July 2012 are depicted below in a worldwide map prepared by the National Climatic Data Center:

Selected Significant Climate Anomalies & Events July 2012
NOAA National Climatic Data Center

Your descendants shall gather your fruits.
~ Virgil

References

• Hottest Month Ever Recorded. NOAA Climate.gov. Wednesday, August 8, 2012
• Mapping The Hot Summer. NASA Earth Observatory.
• GISS Surface Temperature Analysis (GISTEMP). NASA.
• Perception of Climate Change by James Hansen, Makiko Sato, and Reto Ruedy. Proceedings of the National Academy of Sciences of the United States of America, March 2012.
• Brutal July heat a new U.S. record. CNN, August 2012.

Storm Energy Rises

If you have noticed that storms are more intense and more frequent in recent years, a July 2012 report from the Environment America Research and Policy Institute supports your observation.

The report analyzed 60 years of precipitation data dating back to 1948. Extreme downpours are up 30% in the US.

Analysis of nationwide data compiled by the National Climatic Data Center reveal that:

• Heavy downpours that used to occur once every 12 months, now occur every 9 months on average; and
• The largest yearly storms produce 10% more precipitation than they did 65 years ago.

Changes in Downpour Frequency from When it Rains it Pours.

He turned to look just in time to see the rain start falling out as if the storm had finally decided to weep with shame for what it had done to them.
― James Dashner, The Scorch Trials

The report notes that an increase in the number of downpours does not necessarily mean that more water will be available. Climatologists project that the pattern of extreme downpours after longer periods of relative dryness will continue. That is, periods of sparse precipitation will continue to be punctuated by heavy storms.

Gonna be a real frog-strangling turd-floater.
― Charles Martin, Chasing Fireflies

Temperature Effects

Rising land and ocean temperatures serve to increase the intensity of storms in two fundamental ways:

1. Warmer land and ocean temperatures cause water to evaporate faster; and
2. Warmer air temperatures allow the atmosphere to hold more water vapor. 

Today's clouds are richer with moisture so that heavy downpours, or snowstorms, are more likely to occur (cf. Rain from Clouds).

Genius is present in every age, but the men carrying it within them remain benumbed unless extraordinary events occur to heat up and melt the mass so that it flows forth.
― Denis Diderot (1713-1784)

References

• New Report: Extreme Downpours Up 30 Percent, July 31, 2012, Nathan Willcox, Environment America.
• Storms are bigger, wetter, and more frequent than 60 years ago, Philip Bump, Grist.
• Extreme Summer Storms Could Tear us a new Ozone Hole, Philip Bump, Grist.
• Rain from Clouds, July 28, 2012, GrokEarth.
• When it Rains, it Pours Global Warming and the Increase in Extreme Precipitation from 1948 to 2011, July 31, 2012, Environment America.