NotesVI

Wallowa Lake, Oregon, Spring 2009

©EOP

I am going to be out of the country until mid September, so this may be the last posting for awhile—do not know how much time to write or what kind of internet connexion I may have.

A correction of an error: several postings back I talked of el Niño conditions leading to more rain in the southwestern United States, a correct statement, but I also commented that there would be some refilling of Lake Mead and the other reservoirs on the Colorado. In fact, despite the rains, the drought has not broken, and Lake Mead has continued to loose water. Now the post el Niño condition called la Niña (a heresy for anyone who believes in Christian mythology, for el Niño means the Christ child and la Niña would mean the female equivalent!) promises yet more dry weather. Only slightly broken by the winter of 2010, the drought is the longest recorded for the southwest.

The post el Niño conditions projected for California and the southwest are dire, especially as there is evidence the period may also be warmer than normal. Higher rates of evapo-transpiration with warmer air temperatures increase the severity of the already serious drought. If it should continue several more years, there could be a real water supply crisis in the region including water for Los Angeles, Las Vegas and Phoenix.

Flood conditions in Pakistan are far worse than first described. The official death toll remains suspiciously low, but it has been estimated that 20 million have lost their homes and as much as a fifth of the country's land has suffered severe damage from the flood waters. The rains have not yet stopped, and thus the flooding could continue for some time. The displaced population is about the same as the total population of New York State, and the land area estimated to have suffered damage is greater than the land area of the Empire State! The area still covered by flood water and that damaged by high water includes some of the most productive farm land in Pakistan. Food production and the production of cotton and other crops are devastated for this growing season. Water borne disease has already been recorded, and it is not far fetched to worry about epidemic cholera, typhus, typhoid and possible malaria along with a variety of other gastro-intestinal problems. Large sums of money and other types of aid have been promised by various countries and international organisations, but much of that aid is likely to arrive too late to prevent one of the greater humanitarian catastrophes of recent years. The political dimensions can at present only be estimated, but it is hard to see how Pakistan's feeble civilian government will be able to cope.


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Droughts and Floods

Navy Memorial Fountain, Pennsylvania Avenue NW, Washington, DC 2010

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Todays feed from Huffington Post includes a rather apocalyptic piece by Toby Barlow "Let's Call it Climate Chaos." I have enough experience with both climatology and statistics to realize that the current nexus of climate related issues worldwide is in itself neither proof nor disproof of climate change—only trends over a longer period can serve that purpose—but current conditions give powerful reasons to fret about the future of a warmer world. Those of us unfortunate enough to live in the Mid-Atlantic states have experienced a prolonged spell of very hot and uncomfortable weather, though neither New York nor Washington, DC actually set new records for the month of July, merely matching older ones. Just the discomfort of hotter summers is adequate to make one hope global warming is limited to only a few degrees at most. It is clear that warming has many effects, most of them much scarier than simple discomfort.

Source: Novosti Infographics

Much of European Russia has had one of its hottest and driest summers ever. It seems that Moscow is posting new heat records almost daily even as its residents are forced to breathe smoke filled air from countless brush, field, and forest fires in the surrounding region. In addition to the dessicating heat, rainfall in the breadbasket areas south of Moscow are far below long term norms with some areas receiving only a tiny fraction of the precipitation expected. Grain yields are in turn now expected to be well below long-term averages, and it will soon be too late, if it is not already, for additional rainfall to benefit the current year's crop. The expected deficit in grain production is likely to raise world grain prices, for it has already raised grain futures.

The drought in Russia points to the changes in the global distribution of precipitation during a hotter Northern Hemisphere summer. The summer of 2010 is entrain to be the hottest ever recorded (just as the 2009-10 winter was the warmest recorded). Common to post el Niño seasons, the southwestern United States, including Southern California and the lower Colorado River Basin has enjoyed above average rainfall, somewhat breaking the years long drought. That has started to refill the various reservoirs, though it is unlikely to leave Lake Mead, Lake Powell or the others anything close to bank-full. For the moment at least, a drought has been broken in an area where water supplies are historically very limited.

In Asia excess rainfall is the issue with deadly flooding in both Pakistan and China. Pakistanis wish for rain in the wet part of the monsoon in mid to late summer, but this year has brought rainfall far in excess of long term averages, and 1,000 or more people have been killed by flood-related causes even as bridges, roads, and rail lines have been severed, towns destroyed, and agricultural areas devastated as rushing waters was away topsoil and growing crops. Instead of providing needed water for crops, the monsoonal rainfall of 2010 has caused massive damage. The situation in southern China is similar to that in Pakistan, though it is a function of typhoon circulation rather than the Asian Monsoon. 

The combined effects of these weather conditions, especially droughts and flooding, could have substantial impact on food prices throughout the world. European Russia and southern China export food to other parts of those countries and to world markets. Pakistan is a net food importer, and destruction of good agricultural land is likely to lead to greater demands for imported food. The combination of reduced production and demand from those areas made unproductive by drought and flood is almost certain to led to increased prices for at least some commodities. Those price increases are already apparent in world agricultural markets.

Once again it is important to note that the current summer is not in itself evidence for climate change, but it offers us a shocking preview of what warmer global temperatures portend. From the point of view of water supplies, a massive global redistribution of precipitation will be making some areas much drier than they have been in the past while other areas suffer from excessive precipitation. Severe storms are likely to become much more common, and 100-year floods may become 10-year floods. Instead of being expected not more than once in a century, those water levels will be expected once a decade. Some presently habitable areas will be erased from the map by flooding (granted other areas currently uninhabitable may be added to the ecumene but a net loss of usable land is the most likely outcome), while others will become too dry to use for crops. The world's food supplies are likely to be reduced and food prices increased by the combined effects of drought, flooding, and loss of land accompanying an increase in average world temperatures. It is all quite scary to contemplate!

Image via Wikipedia

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Drought I

2006 Drought, Union County, New Mexico

© EOP

Today the Los Angeles Times stated "California's drought may be over, but no one's rushing to lift restrictions."  Meanwhile, in a story posted on Huffington Post.com  the former BBC reporter and current Oxfam representative Caroline Gluck wrote "Millions face severe hunger in Niger." Both the southwestern quadrant of the United States and the Sahel region of Africa have been through prolonged dry spells, drought that put severe strains on water supplies. In Southern California that means a little less water for the garden and restrictions on using water to wash cars and sidewalks. In Niger it may well mean mass hunger or even famine. The el Niño conditions of the past autumn and winter brought rainfall to the southwestern region of the US, and for the first time in several years runoff and stream flow have allowed reservoirs to be filled and discussion of lifting restrictions on water use. No such relief is in sight for the Sahel, and while food is available in the markets of towns and cities, subsistence farmers face starvation because they lack the means to purchase food and their fields are unproductive.

Drought is one of the most difficult of natural conditions to predict and even to define. Most climates are characterized by annual dry spells. Mediterranean climates like that of California have dry summers with most of the precipitation falling in the cooler months of autumn and winter. Monsoonal climates, the climate of south Asia, are characterized by a dry cool season and heavy rain during the summer months. Adaptation to annual variation is not too difficult if there is adequate precipitation in the rainy season. In a drought wet season precipitation is inadequate to meet dry season demands. If that absence of precipitation should extend over a number of years, the drought is considered severe.

The most famous drought in the United States was that of the 1930s when "dust bowl" conditions prevailed over a large swath of land extending south from the Dakotas to Texas on the High Plains, the western margins of the Great Plains. The Seattle writer Tim Egan tells the story of the drought in the region where Colorado, Kansas, New Mexico, Oklahoma, and Texas adjoin (including Union County, NM pictured above) in his harrowing The Worst Hard Time. While dust storms and similar conditions have not returned, that same region has been under severe water stress over the past 5 years, a drought that has cut agricultural production and led to some economic dislocations. Only widespread use of ground water from the Oglalla aquifer has allowed field crops to thrive in the region.

In future postings we shall examine both drought and groundwater resources in more detail.