Search Results : 20 » Geo-Mexico, the geography of Mexico » Page 42

May 102012
 

In the past few days, Popocatepetl Volcano has continued to emit gas, steam and ashes, periodically shooting ash-laden clouds high into the sky. The columns of ash have risen up to 2500 meters above the volcano before drifting downwind. Depending on the wind direction at the time, light falls of ash have been reported from Mexico City (especially the Milpa Alta and Iztapalapa districts) and the city of Puebla.

Ash cloud rises above Popocatepetl

Ash cloud rises above Popocatepetl Volcano

The National University’s Atmospheric Sciences Institute has developed atmospheric models taking account of the volcanic emissions and is releasing regular forecasts of where ash is likely to fall.

Ramón Espinasa Pereña, who heads the Geological Risks department in the National Disaster Prevention Centre (Centro Nacional de Prevención de Desastres, Cenapred) expressed concern recently that Popocatepetl Volcano could be headed towards much more significant activity in coming weeks.

In an interview with Mexico City daily Excelsior, Espinasa started by saying that that the current level of activity is less than that experienced in 2000 when the volcano’s heat caused the melting of the glacier then found on the northwest side of the mountain. However, he added, the situation today is quite different. The dome of lava inside the crater of Popocatepetl Volcano has been growing, increasing the risks of a significant and possibly explosive eruption. In 1994, prior to the 2000 eruption, the crater of the volcano was about 800 meters long, 600 meters wide and 100 meters deep. The activity in 2000 raised successive domes of lava in the crater to within 20 or 30 meters of the crater rim. So far this year, the depth of the crater has remained about the same, but only because almost all the new material being added to the existing domes is being blown into the air.

Experts are concerned that the high density of the magma beneath the volcano may lead to the existing vents being blocked. If this happens, pressure will build up underground and greatly increase the possibility of a violent eruption.

Evacuation plans have been in place since 1994, and they have been modified and updated regularly since. There are ten major evacuation routes (see map). The villages most at risk (inside the 12-kilometer radius “high risk” zone) include several in the states of Puebla (San Nicolás de los Ranchos, Santiago Xalitzintla, San Pedro Benito Juárez, San Baltazar Atlimeyaya and Tochimilco), Morelos (Ocuituco, Tetela del Volcán, Yecapixtla, Zacualpan de Amilpas and Temoac) and the State of México (Tepetlixpa, Ozumba, Atlautla, Ecatzingo and Amecameca).

Popocatepetl Volcano: the planned evacuation routes

Popocatepetl Volcano: the planned evacuation routes

Last week, the evacuation system (that will only be put into effect if the risk level rises) was tested with a large-scale practice evacuation in which the Mexican Army assisted municipal and state officials and emergency response crews. The practice has enabled authorities to improve the forecasts of precisely how long it will take to evacuate all villagers from the likely danger zone, in the event that the risk level is raised.

Evacuation will not be easy. Some local inhabitants argue that the volcano has never caused them any harm, because, on the contrary, it is their “protector and guide”. They are unlikely to move voluntarily even if an eruption is imminent. They hold a festival each year on 12 March thanking the volcano for its rich soil, abundant rainfall and “to keep the volcano calm and happy.” The ceremonies include the placing of offerings part-way up the volcano, accompanied by folk dancing.

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May 072012
 

Alexander von Humboldt‘s visit to Mexico began in Acapulco on March 22, 1803, and lasted for almost a year. (He left Mexico via Veracruz for the USA on March 7, 1804.) In his year in Mexico, Humboldt had been incredibly busy. He had measured, recorded, observed and written about anything and everything, with remarkable industry and accuracy. He had climbed mountains, burned his boots on active volcanoes, descended into mines, recorded geographical coordinates, and collected numerous specimens and antiquities. Humboldt’s Political Essay on the Kingdom of New Spain was the first systematic scientific description of the New World. It appeared in 1811, and marked the birth of modern geography in Mexico. His figures and ideas were used and quoted by writers for many many years.

Humboldt had also drawn a large number of maps, drawings and sketches and it can rightly be claimed that the modern era of Mexican map-making began with Alexander von Humboldt, and was then developed further later in the 19th century by cartographers such as Antonio García Cubas.

Humboldt's route in Mexico

Humboldt's route in Mexico. Click to enlarge

Alexander von Humboldt (Self-portrait c1814)

Alexander von Humboldt (Self-portrait c1814)

The map above shows the route followed by Humboldt during his time in Mexico. The map comes from the book La obra de Alexander von Humboldt en México by Rayfred Lionel Stevens-Middleton  (Mexico D.F.: Instituto Panamericano de Geografía e Historía, 1956). This hard-to-find work is a comprehensive account of Humboldt’s time in Mexico and of his significance for the development of what the author refers to as “modern geography”.

The map of Humboldt’s route in Mexico includes his various side trips such as those to Jorullo Volcano and Santa María Regla.

Humboldt was keen to see Jorullo Volcano, since it was a rare example of a brand new volcano, one of only a handful of volcanoes that have emerged on land anywhere in the world in historic times. Jorullo first erupted on 29 September 1759 and activity continued for 15 years until 1774. Two centuries later, and about 80 km (50 miles) away, Paricutín Volcano burst into action for the first time, in a farmer’s field in 1943.

Santa María Regla, in the state of Hidalgo, about an hour’s drive north of Mexico City, is the best known location in Mexico for basalt columns. The columns, up to 40 meters tall,  are attractively located on the side of a canyon, with a waterfall tumbling over some of them:

Despite only seeing a relatively small part of the country (New Spain as it then was), Humboldt was able to make some generalizations about geography in general, and Mexican geography in particular, that have stood the test of time remarkably well. For example, he was the first to describe the vertical differentiation of climatic and vegetation zones in Mexico. Writing in 1811, he proposed the terms tierra caliente, tierra templada, and tierra fría, terms still widely used by non-specialists today:

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May 052012
 

Much recent attention in the USA and Mexico has focused on the allegations of bribery related to Wal-Mart de México.  Interestingly, the company has a rather long history in Mexico. It started in 1958 when Jerónimo Arango and his brothers Placido and Manual started a company called Cifra and opened a deep discount store in Mexico City named Aurrera Bolivar. It was inspired by the E.J. Korvette discount store in New York City. The store was an immediate success, helped by sponsorship of the popular TV show, La Pregunta de los $64,000 pesos (“The $64,000 Pesos Question”).

Wal-Mart's expansion across Mexico, 1993-2007

Wal-Mart's expansion across Mexico, 1993-2007. Click map to enlarge

By 1965 Cifra had eight Aurrera stores in the Mexico City area as well as a Superama grocery store and VIPS restaurant. Cifra and Jewel-Osco of Chicago formed a joint venture and by 1970 they opened the first Bodega Aurrera discount warehouse stores and Suburbia department stores. Their first hypermarket, Gran Bazar, followed in 1976. Shares in the company were sold to the public in 1977.   By serving low-income customers, the company managed to survive the financial crisis of 1982.  In fact during the 1980s it increased sales by an average 20% per year reaching US$550 million by 1989.

Rapid growth continued in the 1990s. By 1992 there were 38 Almacenes Aurrera supermarkets, 29 Bodega Aurreras, 34 Superamas, 29 Suburbias (department stores), 59 VIPS, as well as 15 El Portón restaurants. Almost all of these were located in the densely populated Mexico City and surrounding State of Mexico. Phenomenal growth continued in 1992 with 23 new units added. Cifra B shares increased forty-fold in just five years from the start of 1988 through the end of 1992. At that time, Cifra had a sophisticated, state-of-the-art data system for inventory control and monitoring customer preferences.

In 1991 Cifra formed a joint venture with the US firm Wal-Mart (founded in 1962, four years after Cifra). Unlike Cifra, whose early growth was based on an enormous urban area, Wal-Mart USA’s incredible early growth concentrated on rural areas. Initially the joint venture focused on trade and the members’ only Club Aurrera, which was soon renamed Sam’s Club. The first map shows the distribution of Wal-Mart stores in 1993. Expansion of new outlets throughout Mexico was only slightly slowed by the 1994 financial crisis.

By 1995, there were 22 Sam’s Clubs, and 11 Wal-Marts, 35 Almacenes Aurrera, 58 Bodegas Aurrera, 36 Superamas, 33 Suburbias, as well as 114 VIPS restaurants. One of the new Wal-Mart Supercenters was the largest in the world. The signing of NAFTA in 1994 strengthened the joint venture. In 1997 Wal-Mart USA acquired majority interest in Cifra creating Wal-Mart de Mexico or Walmex. The company, which previously had been heavily concentrated in Metro Mexico City, was soon aggressively opening new units in cities throughout the country (see maps).

Recent news reports allege that this aggressive growth may have been facilitated by payments of bribes to expedite construction permits. As of March 2012, Walmex was operating no fewer than 2,106 retail units throughout Mexico. They include 127 Sam’s Clubs, 213 Walmart Supercenters, 94 Suburbias, 385 Bodega Aurreras, 88 Superamas, 358 VIPS and El Portón restaurants, and over 840 Bodega Aurrera Expresses and other small outlets.

Wal-Mart de México is the country’s largest retailer, with sales of over US$24 billion, and largest private-sector employer, with 209,000 employees. These figures make Walmex the dominant player in its sector, well ahead of its Mexican supermarket rivals: Soriana ($8 billion); Comercial Mexicana (Mega, $4.5 billion) and Chedraui ($4.4 billion).

The 2007 map shows how Wal-Mart has now expanded into some areas where the population density is relatively low. The early expansion of Wal-Mart was into areas with high population density, where a single, well-placed store could easily be accessed by a lot of people, and therefore have the potential to be highly profitable. Even with the 2007 distribution, however, there is still a marked north-south divide in access to Wal-Mart, which reflects income disparities in Mexico.

In 2009/10 Walmex acquired Walmart Centroamérica and is now named Wal-Mart de México y Centroamérica, adding 622 retail outlets in Guatemala, El Salvador, Honduras, Nicaragua and Costa Rica, to bring the total number of units it operates (including Mexico) to 2, 728 retail outlets (with sales of about $29 billion) compared to Wal-Mart USA’s 4,468 outlets (with 2011 sales of $447 billion).

Source for maps:  

The maps have been redrawn, based on maps in “Supplier Responses to Wal-Mart’s Invasion of Mexico”  by Leonardo Iacovone, Beata Smarzynska Javorcik, Wolfgang Keller, James R. Tybout. Working Paper 17204  of the National Bureau of Economic Research, Cambridge, MA, USA.

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Apr 302012
 

In a previous post, we saw how most of Mexico’s volcanoes are located in a broad band that crosses central Mexico known as the Volcanic Axis (Eje neovolcánico). In this post, we provide brief descriptions of some of the major volcanoes in Mexico.

Starting in the west, the first active volcanoes are Everman and Barcenas in the Revillagigedo Islands. Two of the westernmost volcanoes on the mainland are near Colima. At 4260 m (13,976 ft), the inactive Nevado of Colima, Mexico’s sixth-highest peak, is as tall as the highest mountains in the contiguous USA. Its younger brother, Colima Volcano (or Volcán de Fuego) is lower (3820 m) but highly active and considered potentially very dangerous. It has erupted in cycles for several hundred years, and is capped by a dacitic plug characteristic of a silica-rich Pelean volcano. Such volcanoes have the potential to erupt suddenly, not emitting vast quantities of molten lava, but shooting out less spectacular, but far more devastating, clouds of red‑hot asphyxiating gasses.

Tequila Volcano, overlooking the town where the beverage is distilled, is also in Jalisco. In neighboring Michoacán state, the most noteworthy volcanoes are Jorullo (which last erupted in 1759) and Paricutín, which began life in a farmer’s field in 1943 and ceased activity in 1952, but only after its lava had overwhelmed several small villages.

Closer to Mexico City, the Nevado of Toluca (4680 m) has a drive-in crater and is a favored destination for Mexico City families in winter to take their children to play in the snow. It is Mexico’s fourth highest peak (see table below).

VolcanoStatesHeight (meters)Height (feet)
Pico de OrizabaVeracruz; Puebla5 61018 406
PopocatapetlMéxico; Morelos; Puebla5 50018 045
IztaccihuatlMéxico; Puebla5 22017 126
Nevado of Toluca México 4 68015 354
MalincheTlaxcala; Puebla4 42014 501
Nevado of Colima Jalisco4 26013 976
Cofre de PeroteVeracruz 4 20013 780
TacanáChiapas 4 08013 386
TelapónMéxico 4 06013 320
El AjuscoFederal District3 93012 894
Colima VolcanoJalisco; Colima3 82012 533

Continuing eastwards, we reach several other volcanoes that are among Mexico’s highest volcanic peaks (and are also included in the table).

The most famous volcano in the Volcanic Axis is the still active Popocatepetl (“Popo”), which rises to 5500 meters (18,045 feet). Alongside Popocatepetl is the dormant volcanic peak of Iztaccihuatl (5220 m or 17,126 ft). On a smog-free day, both are clearly visible from Mexico City. The southern suburbs of Mexico City are overshadowed by a smaller active volcano, Ajusco, which reaches 3930 m (12,894 ft).

The Nevado de Toluca volcano

The Pico de Orizaba, a dormant volcano on the border between states of Veracruz and Puebla, is Mexico’s highest mountain. At 5610 m (18,406 ft) it is the third highest peak in North America. By way of contrast, not very far away, in the outskirts of the city of Puebla, is the world’s smallest volcano!

Only a few volcanoes appear to be located outside the Volcanic Axis and therefore in an anomalous location to the general pattern. They include two volcanoes in Chiapas which lie south of the Volcanic Axis: El Chichón (which erupted in 1982) and Tacaná (4080 m).

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Apr 282012
 

How can we measure the health of forests and other forms of natural vegetation? It has become commonplace to read about biodiversity and many conservation programs rightly stress its importance in the global scheme of things. In a previous post, we examined the biodiversity of Mexico and saw how it is one of the most biodiverse countries in the world.

Biodiversity may be a useful indicator of likely ecological resilience in the face of changing circumstances such as global climate change, but it does not tell the whole picture. In simple biodiversity measures, each species is counted and treated as being equally important. Species close to extinction are singled out for conservation efforts in an attempt to preserve a viable wild population of that species. If all else fails, specimens are transferred to botanical gardens or seeds are collected and stored in the hope that the species can be reintroduced and reestablished in a suitable location at some point in the future.

Biomass production in Mexico (Trees and bushes)

Biomass density in Mexico (trees and shrubs); from deJong et al, 2006.

But are all plant species equal? Should a giant redwood count the same as a dandelion? Certainly in terms of their ability to store carbon, larger plants are more valuable than smaller plants, though the total number of each species also matters. Storing carbon is important. When trees are cut down and burned (to clear the way for agriculture or settlement, for example) this stored carbon is released into the air and contributes to the processes causing global warming.

The term biomass is used to describe the total mass of living organic matter in a plant or in an area. The total biomass of a plant includes its bark, leaves and twigs. In a tropical forest, biomass includes every tree, shrub, sapling, vine, epiphyte and flower. About 50% of the biomass in most forests is carbon. The amount of biomass varies seasonally and is not necessarily stable over time, since plants increase their biomass as they grow. In a forest, the balance that matters in terms of sustainable forestry is the balance between the forest’s production of “new” biomass (through photosynthesis) and the consumption of some of its biomass by chopping, burning and natural decay. Clearly, human activity can directly impact this balance, but so too can natural events such as forest fires.

Bio-geographers have a great interest in assessing biomass since it provides a starting point for numerous models that attempt to estimate the effects of releasing some, or all, of this stored carbon on future global climates. Increasingly, their estimates from the use of remote sensing and satellite images are proving to be quite reliable when tested by comparing them to the biomass of the same area calculated from on-the-ground fieldwork.

The measure of biomass shown on the map is biomass density. Biomass density is the total amount of above ground living organic matter expressed as oven-dry metric tons per hectare. This map immediately reveals why conserving Mexico’s southern rainforests is so important. They are not only the most biodiverse areas of Mexico, their high biomass density values show that they also have far more than their fair share of Mexico’s total biomass. Conserving and managing these forests therefore needs to be a priority strategy in Mexico’s efforts to limit and mitigate climate change.

Sources:

The map comes from Advances of Mexico in preparing for REDD by Bernardus H.J. de Jong, Leonel Iglesias Gutiérrez and José Armando Alanís de la Rosa. Presentation given at the UNFCCC Workshop on Methodological Issues relating to Reducing Emissions from Deforestation and Forest Degradation in Developing Countries. Tokyo, Japan, 25 to 27 June 2008.

To read more about estimating biomass, see Estimating Biomass and Biomass Change of Tropical Forests: a Primer. (FAO Forestry Paper – 134) by Sandra Brown. FAO Forestry Paper 134. 1997.

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Apr 262012
 

The following are extracts from the text of a press release from the Pew Hispanic Center entitled “Net Migration from Mexico Falls to Zero—and Perhaps Less“, by Jeffrey Passel, D’Vera Cohn and Ana Gonzalez-Barrera:

The largest wave of immigration in history from a single country to the United States has come to a standstill. After four decades that brought 12 million current immigrants—more than half of whom came illegally—the net migration flow from Mexico to the United States has stopped—and may have reversed, according to a new analysis by the Pew Hispanic Center of multiple government data sets from both countries. The report is based on the Center’s analysis of data from five different Mexican government sources and four U.S. government sources. [see original article for sources]

The standstill appears to be the result of many factors, including the weakened U.S. job and housing construction markets, heightened border enforcement, a rise in deportations, the growing dangers associated with illegal border crossings, the long-term decline in Mexico’s birth rates and changing economic conditions in Mexico.

Among the report’s key findings:

  • In the five-year period from 2005 to 2010, about 1.4 million Mexicans immigrated to the United States and about 1.4 million Mexican immigrants and their U.S.-born children moved from the United States to Mexico.
  • In the five-year period a decade earlier (1995 to 2000), about 3 million Mexicans had immigrated to the U.S. and fewer than 700,000 Mexicans and their U.S. born-children had moved from the U.S. to Mexico.
  • This sharp downward trend in net migration has led to the first significant decrease in at least two decades in the number of unauthorized Mexican immigrants living in the U.S.—to 6.1 million in 2011, down from a peak of nearly 7 million in 2007.
  • Mexicans now comprise about 58% of the unauthorized immigrants living in the United States. They also account for 30% of all U.S. immigrants.
  • Apprehensions of Mexicans trying to cross the border illegally have plummeted by more than 70% in recent years, from more than 1 million in 2005 to 286,000 in 2011—a likely indication that fewer unauthorized immigrants are trying to cross.
  • As apprehensions at the border have declined, deportations of unauthorized Mexican immigrants—some of them picked up at work or after being arrested for other criminal violations—have risen to record levels. In 2010, nearly 400,000 unauthorized immigrants—73% of them Mexicans—were deported by U.S. authorities.
  • Looking back over the entire span of U.S. history, no country has ever sent as many immigrants to this country as Mexico has in the past four decades. However, when measured not in absolute numbers but as a share of the immigrant population at the time, immigration waves from Germany and Ireland in the late 19th century equaled or exceeded the modern wave from Mexico.

– – – end of quotations from press release – – –

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Apr 222012
 

Popocatepetl is Mexico’s second largest volcano, after El Pico de Orizaba. Popocatepetl rises to a height of 5500 meters (18,045 feet) and is located approximately mid-way between Mexico City, about 80 kilometers (50 miles) to the northwest, and the city of Puebla, a similar distance to the east.

In the past week, Popocatepetl (aka “Popo” or “Don Goyo”) has sprung back into life, blowing off steam and ash in a series of minor eruptions, accompanied by minor earth tremors, many of which registered between 3 and 4 on the Richter scale. Incandescent rocks (“volcanic bombs”) have been thrown up to 1000 meters (3000 feet) from the crater down the slopes of volcano, and water vapor, gasses and ash have formed towering clouds, up to 2000 meters high, rising above the iconic volcano.

Popocatapetl lets off steam. Credit: Victor Hugo Rojas (Universal)

Popocatepetl lets off steam. Credit: Victor Hugo Rojas (Universal)

The latest eruptions of Popocatepetl come from an estimated sixty different vents that are connected to a magma chamber 10 km (6 miles) beneath the volcano that is thought to hold upwards of 1,000,000 cubic meters (36,000,000 cubic feet) of magma. On the one hand, the small eruptions are good news, since they relieve the pressure building up underground, at least temporarily. On the other hand, they may presage a much more serious and major eruption.

Thousands of families live in the farming villages on the lower slopes of the volcano; some 25 million people live within a 100 kilometer (60 mile) radius. In the event of a major eruption, and depending on wind directions, airborne ash could fall on Mexico City, interrupting normal activities and Mexico City’s busy international airport, or on the Metropolitan area of Puebla (population 2.7 million), an important industrial center, where Volkswagen has its main vehicle factory.

Even though geophysicists are unable to say whether or when a major eruption will actually occur, authorities have raised the threat level and taken steps to ensure that local residents can be safely evacuated, if necessary, to emergency shelters in nearby public buildings such as schools. Almost 200 temporary shelters have been prepared in nearby villages to house any people that are forced to leave their homes.

Mexico’s National Disaster Prevention Centre (El Centro Nacional de Prevención de Desastres, Cenapred) has raised the alert level to “yellow stage three” – the third highest level. This level indicates that a magma expulsion is possible and that the intensity of explosions is likely to increase.

In the event that the alert is raised still further, into the red zone, villages within a 12-km zone will be immediately evacuated, and the exclusion zone may be extended still further if this is deemed a prudent safety measure. During the last major evacuation, in 2000, nearly 50,000 residents in three states were moved into temporary shelters.

As in the case of previous volcanic eruptions in Mexico, such as Paricutín in the 1940s, the Mexican Army would take charge of ensuring that local residents are taken to safety.

Roads are being kept open, and emergency repaving is underway, in case an evacuation is required. Local villages are arranging to have sufficient buses standing by to ensure that their residents can be evacuated rapidly should the alert level be raised. Even so, it is unlikely that everyone would choose to leave, and it is thought that up to half the population might attempt to remain in their homes even if the alert level is raised.

Images of the volcano:

Health authorities have already distributed free face masks and bottles of water to families in the area. The cloth face masks are intended to filter out the fine ash released by the volcano, and reduce the likely increase in respiratory problems. Falling ash is also expected to lead to an increased incidence of allergic conjunctivitis.

Authorities in the city of Puebla have temporarily suspended open air activities until further notice since much of the city has received a thin layer of ash. Ash falls of about one centimeter have been reported in some districts of the city. Ash has also fallen over the nearby town of Cholula and as far away as Atlixco and Huejotzingo.

Puebla hoteliers, restauranteurs and merchants will be hoping that the city’s restriction on open air activities ends quickly, since the city is gearing up for the annual festivities associated with the 5 de Mayo (5 May) festival for which the city is famous. (The festival commemorates Mexico’s victory over French forces at the Battle of Puebla on 5 May 1862).

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Apr 212012
 

Despite this being an obvious question, there is no simple or generally accepted answer! However, a document published last month by Centro de Estudios Sociales y de Opinión Pública de la Cámara de Diputados (CESOP), entitled Lavado de dinero: indicadores y acciones de gobierno binacionales (“Money Laundering: bi-national indicators and government actions”) does offer some clues and estimates.

For example, according to Mexico’s tax authorities (SHCP), the nation’s financial system “gained” at least 10 billion dollars last year from unrecorded, presumably illicit, activities such as drug trafficking. North of the border, the US State Department believes that money laundering in Mexico accounts for between 8 billion and 25 billion dollars a year, while figures as high as 29 billion dollars have been offered in the US Congress.

Financial models developed by Global Financial Integrity and Columbia University in the City of New York suggest that the total “gains” from all forms of illegal activities in the USA are about 196 billion dollars (1.36% of US GDP), and that about 90% of this amount is laundered each year. The same models, applied to Mexico, suggest total crime-related profits of 38 billion dollars (3.6% of Mexico’s GDP), only 10-14 billion dollars of which is laundered into the formal economy.

If the models are to be believed, in the USA, 46% of the total amount laundered derives from drug trafficking, 32% from people trafficking, 15% from pirated goods and 7% from fraud. In Mexico, 41% of laundered money originates from drugs, 33% from people trafficking, 20% from pirated goods and 6% from fraud.

Despite the considerable variation in numbers, most of the figures and calculations fall within, or close to, the range of values (between 2 and 5% of global GDP) that is estimated by the International Monetary Fund to be laundered each year around the world.

Apr 192012
 

Mexico’s active seismic zones have created numerous volcanoes, many of which are still active. Virtually all the country’s active and recently dormant volcanoes are located in a broad belt of high relief which crosses Mexico from west to east: the Volcanic Axis (see map).

volcanic-axisAltitudes in this region vary from a few hundred to several thousand meters. The principal peaks are shown on the map. They include many of Mexico’s most famous mountains, such as Popocatepetl and Iztaccihuatl, near Mexico City; Pico de Orizaba, Mexico’s highest peak; Paricutín, the only completely new volcano in the Americas in recent times; and Colima, considered the most active at present. Many of the volcanoes are surprisingly young. For instance, a study using Carbon‑14 dating on the palaeosols (ancient soils) under 12 volcanoes in the Toluca area yielded ages ranging from 38,600 to 8400 years before present.

It is unclear precisely why this broad belt of Mexico should be so active. Elsewhere in the world all major tectonically active areas have been linked in terms of their location to the margins or meeting‑zones of tectonic plates. Some Mexican geologists believe that Mexico’s Volcanic Axis is a rare example of activity associated with a gently dipping plate margin, one where the edge of the Cocos plate is subsumed, but at only moderate gradient, beneath the North American plate.

Almost all the volcanic activity in this zone has taken place in the last 25 million years, from the upper Oligocene period, through the Miocene and Pliocene and up to Recent. Two distinct periods of activity are recognized by some geologists. The first, in the late Oligocene and early Miocene, produced volcanic rocks often found today tightly folded by later earth movements. The second, responsible for all the major composite cones as well as dozens of ash and cinder cones, started in the Pliocene and continues today.

Erosion has had relatively little time to work on these “new” volcanic peaks, some of which are still developing. As a result, this region includes Mexico’s highest mountains, reaching over 5500 m or 18,000 ft.

Thick, lava-rich volcanic soils make this one of the most fertile areas in North America. Though the relief is very rugged, this area has supported relatively high population densities for hundreds of years, including the current large metropolitan areas of Mexico City, Guadalajara and Puebla. Legacies of previous volcanic activity are found in craters, mud‑volcanoes, geothermal activity, and the numerous hot springs (and spa towns) scattered throughout the Volcanic Axis.

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Apr 162012
 

In just 20 years, Mexico has gone from a nation that needed to import less than 400,000 metric tons of corn (maize) a year in order to satisfy its domestic market to one where, in the 2011-12 season, it will need to import almost 10,000,000 tons.

One producers’ organization, Mexico’s National Confederation of Maize Growers (CNPAMM), argues that this reliance on imports has relegated the work done by its members to a relatively minor role in providing the nation with food. The growers claim that the price they receive for corn (post-NAFTA) has declined in the face of cheaper imports, jeopardizing their livelihoods. (For one view of the changes post-NAFTA, see NAFTA Truth and Consequences: Corn).

On the other hand, in the past few years, the costs of imported corn have risen sharply, meaning that consumers have to pay more for their tortillas. In order to preserve some stability, the Mexican government has bought corn futures which guarantee corn prices for a period of time.

How is it possible that the country that gave the world corn is now so dependent on imports of corn, almost all of which come from the USA? According to the CNPAMM, it is the result of speculation, market distortion and failures in Mexico’s economic policy. Héctor Carlos Salazar, the president of CNPAMM, called on maize growers to demand better prices, a reduction in imports, and some guarantees from the politicians fighting this year’s federal elections that they will take steps to ensure Mexico’s self-sufficiency in foodstuffs.

Salazar has been quoted in the press as offering some interesting statistics for the impacts of every additional ton of corn that Mexico imports from abroad. He claims that each ton imported reduces agricultural employment by 4.54 man-hours. It also reduces other inputs: diesel by 6 liters, fertilizers by about 100 kg, insecticides by 1 liter, pesticides by 3 liters and improved seeds by about 4 kg.

The bottom line is that it is not just the food security, particularly of Mexico’s poorest, that is threatened by rising corn imports, it is also Mexico’s economy.

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