Climate change could wipe out 40% of species in Arab world

AMMAN - Arab countries will be devastated by climate change, which threatens to wipe out almost half of the species in the region and transform the Levant into an “infertile crescent”, warned a report released on Sunday.

The “2009 Arab Environment: Climate Change. Impact of Climate Change on Arab Countries” report, released yesterday by the Arab Forum for Environment and Development (AFED), indicated that the phenomenon will lead to fewer water resources, a rise in sea levels, damage bio-diversity and spread diseases throughout the region.

The report, which seeks to address areas impacted by climate change and serve as the basis for future mitigation and adaptation policies, warned that water resources in the Arab region are dwindling and will reach an alarming stage by the year 2025.

It indicated that the Fertile Crescent, lands stretching from Iraq and Syria to Lebanon, Jordan and Palestine, will lose all traits of fertility by the end of the century due to deteriorating water supplies from major rivers and soil erosion.

“With continuing rising temperatures, water flow in the Euphrates River may decrease by 30 per cent and the Jordan River by 80 per cent before the turn of the century,” the report warned.


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Unprecedented. We've never seen this before.

http://en.wikipedia.org/wiki/Sahara

Climate history

The climate of the Sahara has undergone enormous variation between wet and dry over the last few hundred thousand years.<12> During the last glacial period, the Sahara was even bigger than it is today, extending south beyond its current boundaries.<13> The end of the glacial period brought more rain to the Sahara, from about 8000 BC to 6000 BC, perhaps due to low pressure areas over the collapsing ice sheets to the north.<14>
Once the ice sheets were gone, northern Sahara dried out. In the southern Sahara though, the drying trend was soon counteracted by the monsoon, which brought rain further north than it does today. The monsoon is due to heating of air over the land during summer. The hot air rises and pulls in cool, wet air from the ocean, which causes rain. Thus, though it seems counterintuitive, the Sahara was wetter when it received more insolation in the summer. This was caused by a stronger tilt in Earth's axis of orbit than today, and perihelion occurred at the end of July.<15>
By around 3400 BC, the monsoon retreated south to approximately where it is today,<16> leading to the gradual desertification of the Sahara.<17> The Sahara is now as dry as it was about 13,000 years ago.<12> These conditions are responsible for what has been called the Sahara pump theory.
The Sahara has one of the harshest climates in the world. The prevailing north-easterly wind often causes the sand to form sand storms and dust devils.<18> Half of the Sahara receives less than 20 mm (0.79 in) of rain per year, and the rest receives up to 10 cm (3.9 in) per year.<19> The rainfall happens very rarely, but when it does it is usually torrential when it occurs after long dry periods, which can last for years.
The southern boundary of the Sahara, as measured by rainfall, was observed to both advance and retreat between 1980 and 1990. As a result of drought in the Sahel, the southern boundary moved south 130 kilometres (81 mi) overall during that period.<20> Deforestation has also caused the Sahara to advance south in recent years, as trees and bushes continue to be used as fuel source.
Recent signals indicate that the Sahara and surrounding regions are greening due to increased rainfall. Satellites show extensive regreening of the Sahel between 1982 and 2002, and in both Eastern and Western Sahara a more than 20 year long trend of increased grazing areas and flourishing trees and shrubs has been observed by climate scientist Stefan Kröpelin.<21>

http://en.wikipedia.org/wiki/Sahara_pump_theory#Last_Glacial_Maximum

Last Glacial Maximum

An example of the Saharan pump has occurred after the Last Glacial Maximum (LGM). During the Last Glacial Maximum the Sahara desert was more extensive than it is now with the extent of the tropical forests being greatly reduced.<7> During this period, the lower temperatures reduced the strength of the Hadley Cell whereby rising tropical air of the Inter-Tropical Convergence Zone (ITCZ) brings rain to the tropics, while dry descending air, at about 20 degrees north, flows back to the equator and brings desert conditions to this region. This phase is associated with high rates of wind-blown mineral dust, found in marine cores that come from the north tropical Atlantic.
Around 12,500 BC, the amount of dust in the cores in the Bølling/Allerød phase suddenly plummets and shows a period of much wetter conditions in the Sahara, indicating a Dansgaard-Oeschger (DO) event (a sudden warming followed by a slower cooling of the climate). The moister Saharan conditions had begun about 12,500 BC, with the extension of the ITCZ northward in the northern hemisphere summer, bringing moist wet conditions and a savanna climate to the Sahara, which (apart from a short dry spell associated with the Younger Dryas) peaked during the Holocene thermal maximum climatic phase at 4000 BC when mid-latitude temperatures seem to have been between 2 and 3 degrees warmer than in the recent past. Analysis of Nile River deposited sediments in the delta also shows this period had a higher proportion of sediments coming from the Blue Nile, suggesting higher rainfall also in the Ethiopian Highlands. This was caused principally by a stronger monsoonal circulation throughout the sub-tropical regions, affecting India, Arabia and the Sahara. Lake Victoria only recently became the source of the White Nile and dried out almost completely around 15 ka <8>
The sudden subsequent movement of the ITCZ southwards with a Heinrich event (a sudden cooling followed by a slower warming), linked to changes with the El Niño-Southern Oscillation cycle, led to a rapid drying out of the Saharan and Arabian regions, which quickly became desert. This is linked to a marked decline in the scale of the Nile floods between 2700 and 2100 BC. <9>