Watch the Earth transform in front of your eyes in these incredible Google Timelapses
▻http://www.wired.co.uk/article/google-timelapse-satellite-update
The Aral Sea has been drying out since the 1960s due to Soviet irrigation programmes. By 2007 it had been reduced to just 10 per cent of its original volume.
Summer 2014 : The Aral Sea Loses Its Eastern Lobe
▻http://earthobservatory.nasa.gov/IOTD/view.php?id=84437
Et dire que j’avais raté cet événement !
Summer 2014 marked another milestone for the Aral Sea, the once-extensive lake in Central Asia that has been shrinking markedly since the 1960s. For the first time in modern history, the eastern basin of the South Aral Sea has completely dried.
Humans drained the Aral Sea once before – but there are no free refills this time round
▻http://theconversation.com/humans-drained-the-aral-sea-once-before-but-there-are-no-free-refil
The Aral Sea has reached a new low, literally and figuratively; new satellite images from NASA show that, for the first time in its recorded history, the largest basin has completely dried up.
However, the Aral Sea has an interesting history – and as recently as 600-700 years ago it was as small, if not smaller, than today. The Aral recovered from that setback to become the world’s fourth largest lake, but things might not be so easy this time round. Today, more people than ever rely on irrigation from rivers that should instead flow into the sea, and the impact of irrigation is compounded by another new factor: climate change.
Sandwiched between Kazakhstan and Uzbekistan, the Aral Sea is actually a lake, albeit a salty, terminal one. It is salty because evaporation of water from the lake surface is greater than the amount of water being replenishing through rivers flowing in. It is terminal because there is no outflowing river. This makes the Aral Sea very sensitive to variations in its water balance caused either by climate or by humans.
Genghis Khan, conqueror of the world, diverter of rivers.
Hello #Chinggis !, bientôt, ton anniversaire : 24/11/2014, jour férié (mobile) en Mongolie : #Jour_de_la_fierté_mongole
cf. ▻http://seenthis.net/messages/192030
Ceci dit, dans l’article pointé :
We still aren’t sure exactly what caused such extreme regression, but a cooler, drier climate played a role. The 13th century Mongol invasion of central Asia also led to the Amu Dar’ya, one of two major rivers that feed the Aral, being diverted to the Caspian Sea. Clearly humans were a major factor in the Aral’s previous dry spell.
se trouve un lien (sous diverted to the Caspian Sea) malheureusement sous #paywall, mais dont le résumé dit pratiquement le contraire…
Archaeology and climate : Settlement and lake-level changes at the Aral Sea - Boroffka - 2006 - Geoarchaeology - Wiley Online Library
▻http://onlinelibrary.wiley.com/doi/10.1002/gea.20135/abstract
New archaeological and geomorphologic data collected adjacent to the Aral Sea show lake-level stands during the late Pleistocene and the past 5000 years. On the northern and southern shores, archaeological sites from the Palaeolithic through the Late Middle Ages contain evidence of various cultures and economies. Changes in settlement activity during the mid-Holocene are related to several major lake-level oscillations. Some of them, especially those which occurred at approximately 350–450 cal B.P. (during the Little Ice Age), 700–780 cal B.P., around 1400 cal B.P., and 1600–2000 cal B.P., were accompanied by lithological changes in sediment cores retrieved from the Aral Sea and were observed in shoreline shifts. We show that a maximum lake level at 72–73 m above sea level cannot be corroborated. The highest lake level, which was reached at the beginning of the 20th century, probably never exceeded 54–55 m a.s.l. Furthermore, we documented a previously unknown low-level stand at 42–43 m a.s.l. that dated to the Bronze Age (∼4000–3000 B.P.). The regression during 1200–1300 cal A.D. was formerly underestimated and was lower than the present-day lake level. The observed environmental changes, except those since the 1960s, are most probably driven by climate variability, though human activities (e.g., irrigation) can amplify the impact.
« La #mer_d_Aral, en Asie centrale, est sur le point de totalement disparaître. Et ce n’est pas la seule étendue d’eau en danger [...] Le #lac_Tchad, le #lac_d_Ourmia, la #mer_Morte ... »
▻http://www.francetvinfo.fr/monde/environnement/en-images-quatre-gigantesques-plans-d-eau-menaces-de-disparition_708841
