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Well, the hot times continue, both globally and locally.  Well ... not so much locally, since we're only running about 2.0°F (1.1°C) above normal 2/3 of the way through August.  No 100° days either. But that's not so true of other locations around the globe, starting with FishOutofWater's diary a week ago, about "hell on earth" in the Southwestern U.S.  That's my opinion about places like Yuma, NV and Needles, CA, without knowing anything about the weather.  I'm sure there's something to appreciate about the stark beauty of a dessicated, dusty landscape, but I'll just stick with mountains and trees, thank you very much!

With that, let's look at the NOAA July 2012 Global Climate Summary.  I did a quick diary on the July 2012 U.S. Climate Summary; last month beat out July 1936, arguably one of the most famous of Dust Bowl months, in becoming the hottest July and hottest month overall on record.  Year-to-date, 2012 has been the warmest Jan.-July period since comprehensive U.S. record-keeping began in 1895 (below). In the graphic below, each year from 1895 through 2012 is plotted, with the 5 warmest years in red and the 5 coldest years in blue.  Note that 2012 stands well-above all those warmest years.

Cumulative temperature anomalies for the 5 coldest and 5 warmest years, and year-to-date for 2012.
Five coldest and five warmest years in continental U.S., cumulative departure from normal temperature as each year evolved, with 2012 added through July.
And the most recent U.S. Drought Monitor (below) looks like a requiem for the crops in the center of the country, though the temperatures have cooled since the records of late July and early August.  The cooler weather was not accompanied by significant rainfall.
U.S. Drought Monitor as of 21 August 2012
U.S. Drought Monitor on 21 August 2012.  Much of the country is in drought, a significant portion of it extreme to exceptional.
Things are not expected to improve for much of the drought area, particularly the area from the mid-Mississippi valley through almost the entire north-to-south expanse of the Great Plains.  This can be seen in the U.S. Drought Outlook product issued last week (below). This outlook is based on something brewing in the tropical Pacific, which I'll discuss later.
U.S. seasonal drought outlook issued 16 August 2012 for period ending 30 November 2012.
U.S. drought outlook issued 16 August 2012 valid through 30 November 2012.
More below the orange wormhole.



Over land and sea globally, July 2012 was the 4th warmest on record. As you already know, it was much warmer than normal over central North America (a.k.a. the continental U.S.).  The graphic below shows the spatial distribution of temperature anomalies over the globe over the 1981-2010 average.

July 2012 global mean temperature anomaly (degrees F)

Northern Europe had a cool, wet July, some of which we saw during the Olympics, though the worst of the weather in England was earlier in the month. It was also cooler than normal in central South America, Alaska, northeastern Siberia, much of Australia, and in much of the Antarctic.  Along with the U.S. and southeastern Canada, it was much warmer than normal over southeastern Europe, the Antarctic Peninsula, parts of the Middle East, and most of central Asia. Note that it was slightly warmer than normal over the area west of tropical South America.  

Land areas experienced the 2nd warmest July on record, with temperatures over 1.5°F above the 1981-2010 normals. Northern Hemisphere land areas were the warmest on record back to 1880 (133 years). Over the oceans it was the 7th warmest July over that period, with the largest warm anomaly since July 2010, as the La Niña cold event that had been tempering global temperatures ended over the tropical Pacific.


Precipitation often varies more than temperature over large regions and globally, and that was true of July 2012. The graphic below shows percentile rankings for the month over the globe.

Global precipitation percentile from 1 to 100 for July 2012.
Percentile ranking of July 2012 precipitation over the globe, from 1 to 100%, and from driest to wettest.
Growing regions adversely affected by drought, besides the U.S., were southeastern Europe, southern and central extratropical South America, much of central Asia and parts of South Asia, including India, where some areas had only 65% of normal (monsoon) rainfall and as a whole, India had only averaged 81% of normal rainfall since 1 June.  Much of China was too wet, which resulted in a mixed bag for agricultural interests.

Soil Moisture

Soil moisture is sometimes called the "memory" of the land surface, since it responds gradually to surpluses and deficits of precipitation.  It's also an indicator of longer-term drought.  Soil moisture globally, using a land surface model that incorporates precipitation, surface temperature, and other meteorological factors, is shown below.

Global soil moisture anomaly percentile ranking, determined using a soil moisture model forced with observed temperature, evaporation, and precipitation.
Global soil moisture percentile rankings for July 2012, over the period starting in 1880.  1st percentile is driest, 99th percentile is wettest.
The extent of dryness is larger than indicated by areas of July 2012 deficient rainfall. The whole central North American continent is dry, in some areas at a record low level. Much of the area from southern Europe through the Middle East and northeastward into central Asia and Siberia are very deficient in soil moisture, as well as approximately the western 2/3 of South Asia.  Much of the breadbasket of Russia (Ukraine) was dry.


Early this summer, the U.S. began to cut its expected 2012 corn yields, and is now projecting a 17% decline in corn production.  Now, as the drought has continued unabated, expected soybean yields are being cut as well, as hoped-for precipitation to save the soybean crop did not generally take place.  The second largest corn grower, Argentina, also suffered a serious drought in its Pampas region, which also reduced yields there.  There have also been problems in places like Ukraine with drought.  

The result?  Reduced expected global corn production of over 4%.  Wheat has also been affected, with expected global yields down about 4% over last year.  Below, we can see what the reduction in supplies has done to food commodity prices.

UN FAO food price index for each year from 2008 through 2012 year to date.  
The U.N. FAO Food Price Index for the last 4 years, and this year through July.
A longer time series of global food prices can be seen below.  Note the volatility and increasing trend since 2004.  
UN FAO Food Commodities Price Indexes for meat, cereals, oils, and sugar. Top:  prices since 1997, with 2002-4 baseline (=100). Bottom: prices since May 2007 to May 2012.
UN FAO Food Commodities Price Indices for meat, cereals, oils, and sugar. Top panel:  prices since 1997 with 2002-2004=100.  Bottom panel: same prices with same baseline from May 2007 to May 2012 (before the drought hit).
Long-Term Effects of Natural Variability on Food Supplies

Finally, the UN FAO Food Price Index since 1990, superimposed onto two of the big climate controllers of multiyear and multidecadal variability in climate related to sea surface temperatures (SSTs):  the Pacific Decadal Oscillation(PDO, 15-25 year period) and 3-5 year El Niño/La Niño cycles. These cycles occur independent of global warming, though there's no guarantee that such natural variability will not be impacted in a warmer world.

Food prices against multidecadal variations and multiyear variations in Pacific sea surface temperatures.
Food prices against multidecadal variations and multiyear variations in Pacific sea surface temperatures.
There is a similar multidecadal phenomenon in the Atlantic Ocean called the Atlantic Multidecadal Oscillation (AMO) that's neglected in the graphic above. The frequency of drought is impacted by both the AMO and the PDO combined.  The graphic below shows how the two act together to impact drought likelihood over the U.S. Plus indicate the positive phase and minus indicate the negative phase of these ocean oscillations.
Likelihood of drought with combined positive/negative phases of Pacific Decadal and Atlantic Multidecadal Oscillations. Expected likelihood is 25%. Red areas have likelihood exceeding 30%.  Blue areas have likelihood less than 20%.
Effect on likelihood of drought from different phases of Atlantic and Pacific sea surface temperature oscillations.  Red has higher likelihood, blue lower likelyhood. Normal climatology is 25%. Contour interval 5%.
This year had a positive AMO and negative PDO, which is the graphic on the lower right.  The fit of likely drought areas to the U.S. Drought Monitor map is quite good in most areas. If you look at the graphic on the upper right, that corresponds to the likelihood of drought in the early to middle 1930s when both indices were positive. That also seems to be a good fit to where the drought existed for the most part, though it also was quite dry into northern TX and much of OK.  So it would seem that natural variability is certainly contributing to the drought problems we're experiencing now.

Outlook for the Next Two Seasons

El Niño is the important player here, and it is expected to manifest over the next couple weeks to a month. The largest impacts from El Niño are in winter and into spring, as can be seen at the Climate Prediction Center's El Niño/La Niña link. Unfortunately, El Niños tend to make the storm track shift south over the U.S. and a less active northern storm track.  This is reflected in both the composite precipitation charts for winterand early spring over the Ohio and mid-Mississippi Valleys in particular.  West of there doesn't look as bad, but it's not likely that it'll be wet enough there to replenish soil moisture stores.  

The wild card is what's going on in the Arctic.  The National Snow and Ice Data Center should reach a record low Arctic sea ice extent in the next couple days. Other centers have already reported record low levels from their analysis methods.  Will the open water of the Arctic Ocean result in unusual blocking in the global circulation, disturbing the expected trends?

How Will Global Warming Contribute to Impacts of Natural Variability on Food Supply?

This question is not that easy to answer, since we're not sure what the effect of global warming will be on these oscillations.  If the oscillations continue, my educated guess is that they will be superimposed on the global warming signal in precipitation.  The impact of global warming on precipitation globally is shown below for (top) December-February and (bottom) June-August mean values. Warm colors are drier, cool colors wetter.

Global shifts in precipitation resulting from the A1B CO2 emission scenario. From the International Panel on Climate Change 2007 report.
Global changes in precipitation in a warming world, using the middle-of-the-road projected increase in CO2 concentration.
Note that precipitation is only one factor in the global warming picture. Additionally, warmer temperatures lead to more demand by crops for soil moisture, thus drawing down the moisture more quickly through evapotranspiration. The North American picture is similar for precipitation:
US expected precipitation change with the A1B scenario for CO2 emissions. From the International Panel on Climate Change.
U.S. changes in precipitation by season for the middle-of-the-road CO2 concentration increases.  Upper left, Dec.-Feb.; upper right, Mar.-May.; lower left, June-Aug.; lower right, Sept.-Nov.  Cool colors are wetter, warm colors drier.
Note the dry southern half of the continent, including in spring and summer some of the most agriculturally productive areas in the world (U.S.).


We need to consider what will affect supply and demand to determine the future of food production and food prices. On the demand side, among other things are:

  • Population increases
  • Increased standard of living impacts on food preferences

The supply side will be controlled by the amount of arable land and by the impacts of climate change. These, to my relatively untrained eye, include

  • The availability of water either from precipitation or from underground aquifers
  • The impact of shifting temperature zones on where things can be grown, and
  • The impact of increased climate variability on the probability of damaging weather events

I'm sure this list is not exhaustive.

Population Increase and Increased Standard of Living

Population growth has been at about 1.1% per year, according to the U.N.  We hit the 7 billion threshold somewhere between October 2011 and March of 2012. One U.N. scenario has population growth stopping at 9.2 billion people at around 2050, and declining thereafter because of the demographic transition to lower birth rates as families become less dependent on their children for food production and the infant mortality rates decline that accompanies increased prosperity. This would require an increase in food production over that time of about 31.4%. Increased living standards require more meat, which in turn requires more grain production for those animals used for meat. These increased standards of living, according to the UN Food and Agricultural Organization (FAO) back in 2009, would result in a need for 70% more food by 2050 to feed a projected extra 2.3 billion people.

Availability of Food and Climate Change

Changes in the global hydrological cycle (how quickly water gets from ocean to atmosphere to land and back) that have been detected over the past 50 years indicate that wet area are getting wetter and dry areas drier, according toAustralian researchers.  Marginal areas for cultivation under such a scenario would become unusable, unless irrigated.  And water for that purpose is becoming scarcer. There has also been both less snow and a speedup of snowmelt in source regions for rivers that provide water for both consumption and crop irrigation, which makes capture of this water more difficult.  

As climate regions shift poleward, it may be that new areas will become useable for agriculture that were not so before, but other factors, such as soil condition, will also be a factor. Even with mostly adequate water, we've seen that extreme heat can cause crops to cease photosynthesis and be damaged (104°F is a critical value). There may be ways of adapting to a warming world by modifying crops to be able to cope with more extremes of drought and temperature, or using a more diverse range of food crops for consumption.  And darn it, we could just stop eating meat, for starters (meat production accounts for 15% of greenhouse gas emissions)!  But things clearly cannot remain as they are with food consumption patterns.  I'm sure others have written about this in other climate SOS diaries.  So I'll leave it at that.


I want to apologize for not being more of an optimist in my diary. It's a difficult thing these days to feel optimistic about the future of us as human beings. The challenges laid out with climate change, food security, and just being a decent citizen of the world (not only the U.S.) are clear.  Rather than a conclusion, I end with a question.  Can we meet the challenges we face?

Originally posted to Climate Change SOS on Fri Aug 24, 2012 at 04:55 PM PDT.

Also republished by J Town, Barriers and Bridges, and Meatless Advocates Meetup.

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