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424 - The dramatic retreat of the Andean glaciers over the last 30 years
February 2013
The glaciers in the tropical Andes shrunk between 30 and 50% in 30 years, which represents the highest rate observed over the last three centuries. IRD researchers and their partners( 1) recently published a summary which chronicles the history of these glaciers since their maximum extension, reached between 1650 and 1730 of our era, in the middle of the Little Ice Age*. The faster melting is due to the rapid climate change which has occurred in the tropics since the 1950s, and in particular since the end of the 1970s, leading to an average temperature rise of 0.7°C in this part of the Andes. At the current pace of their retreat, small glaciers could disappear within the next 10 to 15 years, affecting water supply for the populations.
402 - Exiled ‘brains’ under-employed
April 2012
Who are the Latino-American migrants? What do they do in their host country? The new MICAL observatory( 1), led by IRD researchers, enables the day-to-day study of the movements of this diaspora across the world. Thanks to this data, sociologists are able to describe the massive exile of ‘brains’ that took place in the first half of the 2000s in Latin America. Between 2000 and 2006, the number of expatriate graduates doubled, and today has reached over 3 million. It’s a loss that may be damaging in the country of origin, but can also represent a generalised loss of knowledge: these exiles very often end up under-employed. The percentage of engineers, researchers and other high grades working at an under-qualified level has greatly increased as a result. This was the case in 2006, for example, for three quarters of Bolivian and Ecuadorian migrants
Today the crisis that is currently affecting Spain is modifying or even inverting the migratory trends. A return to the new Latin-American eldorados is increasingly being observed. The consequences of this on the graduates' situation should be monitored closely.
398 - Retreating glaciers are a threat to biodiversity
March 2012
Thawing is taking place the world over as a result of global warming, and the diversity of mountain ecosystems is thus under threat. IRD researchers and their partners( 1), writing in the journal Nature Climate Change , have just revealed that the retreating glaciers may lead to the extinction of between 10 to 40% of aquatic fauna depending on the region - tropical, temperate or arctic. Ecologists have been studying the biodiversity of streams created by meltwater in the the páramos, a typical landscape feature in the Andes) situated at an altitude of between 3,500 and 5,000m. The species that make these streams their home, mostly insects, are endemic to these extreme environments and subjected to a combination of ice and intense sunlight, aggressive winds, etc. The disappearance of such exceptional fauna would lead to a loss in the conservation of such ecosystems, which are unique in the world. However invertebrates also have a role to play as bio-indicators, particularly regarding the quality of the water that supplies downstream towns and cities such as Quito, the capital of Ecuador.
394 - Malaria: how did it reach the Americas?
January 2012
The malaria parasite, Plasmodium falciparum , originates from Africa, and is found on every continent. Over 200 million people are infected every year from Africa to Asia, as well as in America and the Middle East. How did it spread to the entire planet? It is not entirely clear how it conquered the New World. Scientists from the UMR Migevec ( 1) and their partners ( 2) have recently shown in the journal PNAS that the pathogen was introduced by ship during the slave trade. The research team collected samples of infected blood taken across the whole distribution area of the disease. Analysis of genetic material extracted showed that the American P. falciparum is a close cousin of its African counterpart. In addition, two separate genetic groups exist in Latin America, as a result of two distinct slave routes, one towards the Spanish empire in the North – West Indies and present-day Mexico and Colombia – and the other towards the Portuguese empire – today’s Brazil. Nearly half of the 2.7 million annual cases of malaria in America are now occurring in Brazil.
This recent expansion of the disease shows the parasite’s ability to spread.
387 - In search of lost water under glaciers
October 2011
Over 99 % of the Earth’s fresh water exists in ice formations or underground. IRD geophysicists, aiming to find ways of detecting this resource, are at the spearhead in the development of an innovatory method based on nuclear magnetic resonance. To date, it is the only technique applicable for detecting liquid water underground or under a glacier from the surface and for estimating the volume.
This method recently found an original application as an aid for warning of glacier hazard. It successfully detected the presence of an immense water pocket of 55 000 m3 sitting under the Tête Rousse glacier in Haute-Savoie. This posed a flooding threat to people living in the valley below. Warning was given and the local authorities conducted a draining operation.
This technique is adaptable to glacier risk management, but it can also help for water supply provision. It can benefit both tropical mountain areas, such as the Andes or the Himalaya where glacial water can be a major threat, given the context of climate change, and semi-arid regions where water resources lie stored deep underground.
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