martes, 27 de octubre de 2015

Inhabitabilidad


Siguen llegando prognosis específicas sobre los efectos que el actual proceso de aumento global de las temperaturas medias superficiales tendrán en algunas regiones del planeta. Pronostican, por ejemplo, la inhabitabilidad de varias ciudades (actualmente muy prósperas) adyacentes al Golfo Pérsico y al Mar Rojo. Leemos primero en Russia Today en español: 


Título: Varias ciudades de Oriente Medio se harán inhabitables a finales de siglo por las altas temperaturas

Epígrafe: Un nuevo estudio destaca que antes de que acabe el siglo varias ciudades del golfo Pérsico pueden volverse inhabitables si la temperatura sigue subiendo.

Texto: El informe publicado en la revista 'Nature Climate Change' y elaborado por los profesores Elfatih Eltahir y Jeremy Pal responsabiliza de la situación extrema que puede vivirse en el golfo Pérsico al calentamiento global causado por las emisiones de gases de efecto invernadero.

Según la investigación, ciudades como Doha, Abu Dabi y Bandar Abbas podrían sufrir las olas de calor en las que se superen temperaturas de 77ºC, situación en la que el cuerpo humano es incapaz de realizar sus funciones vitales al no poder enfriarse adecuadamente. 

"Se espera que este tipo de olas de calor severas ocurran solo una vez cada diez años o cada pocas décadas", afirma Elfatih A. B. Eltahir, uno de los autores del estudio y profesor del Instituto de Tecnología de Massachusetts. "Pero cuando se produzcan van a ser muy letales", aseveró.

El estudio presagia que incluso sin las olas de calor, las temperaturas extremas de hoy serán algo normal. En algunas ciudades de la región las temperaturas en un día normal de verano superarán los 60°C.

Las olas de calor extremas previstas en el estudio pueden afectar a la industria petrolífera, que es clave para la región, además de otros negocios. El calor extremo también puede poner en peligro la peregrinación del hach, que atrae a millones de musulmanes a La Meca cada año.


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Con algo más de detalle, así cuenta la noticia la publicación Nature Asia el día de hoy:


Título: A chilling vision of a super-heated Gulf?

Subtítulos:  The Arab Gulf is expected to be the epicentre of a severe heat wave / 
Region could endure heat waves of up to 75 °C by century’s end, study predicts

Texto: The Persian/Arab gulf region and parts of southwest Asia could be uninhabitable before the turn of the century as temperatures are expected to rise to intolerable levels.
The apocalyptic scenario is expected to become reality if climate change continues unabated, in the absence of efforts to negate its harmful effects, predicts a new study published today in Nature Climate Change. 

Severe conditions are likely to happen much sooner than was previously thought. 
The cities that are expected to be hit badly are Dubai and Abu Dhabi in the United Arab Emirates, Doha in Qatar and Dhahran in Saudi Arabia.

The study describes an extreme weather condition, “a critical threshold … that could exceed what the human body will be able to tolerate,” according to Elfatih A.B. Eltahir, one of the paper’s authors and a professor of environmental engineering at MIT.
The study uses wet-bulb temperature to measure the potential changes, a variable that describes a combined measure of temperature and humidity. In a heat wave that is expected to last 30 years, between 2071 and 2100, the extreme conditions are predicted to bring up the wet-bulb temperature to 35°C — well over 75°C in the standard heat index. In some areas, even this high threshold will be breached, remarks Jeremy S. Pal, primary author of the paper, and professor of civil engineering and environmental sciences at Loyola Marymount University, California. 

Major heat waves can increase the risk of stroke, particularly for the elderly and the vulnerable. A heat wave of the proportions and impact described in the paper could cause fatalities among perfectly fit and healthy individuals, even in the shade and in the presence of good ventilation. 

“It will pose extremely dangerous conditions for most humans,” says Pal. Temperatures exceeding 53°C – severe heat conditions that usually occur every 20 years in the Gulf – will be the normal summer heat weather for the Gulf under this future scenario.

The body can only handle so much heat – above a certain level, and over extended periods, it becomes impossible for humans to dissipate the heat. This can result in hyperthermia, and possibly death. 

The scientists pinpoint the area around the Persian Gulf and the centre of the Arabian Peninsula as the epicentre of the weather event. The region’s climate is optimal for this extreme scenario owing to factors like the absence of clouds and high incoming solar radiations, its preexisting humid conditions and its warm bodies of water in relatively low areas which increases absorption of solar radiation and increased total heat flux.

This 30-years-of-summer scenario is only likely if current levels of greenhouse gas emissions are not lowered. “[The extreme heat wave] will not be as frequent or not as likely to occur under the mitigation scenario that we consider in our study,” says Eltahir.
The researchers used a climate model with a grid specifically customized for the region, with high-resolution simulations that allow a detailed representation of topography, coastlines, extreme climate events and physical processes. 


The Hajj

The annual ritual of Hajj – a Muslim pilgrimage to Saudi Arabia where pilgrims are exposed to the sun for extended periods – can take place during summer for several years in a row. It is singled out in the study as a major, necessary event for Muslims that could be disrupted as a result of the expected heat wave.

The areas in and around Mecca, according to this scenario, will be among the most vulnerable to the heat wave, with temperatures reaching 66°C. The highest recorded temperature in Mecca since 1980 was 49°C during the summer of 2010. In addition to basic outdoor activities, construction work, oil and gas operations and other sectors are expected to be severely impacted. 

The study also predicts an increase in cases of premature death among children and the elderly and displacement of large populations. Countries with resources can use air-conditioning to brace against the heat, says Eltahir, but this can only protect them indoors. 

The researchers offer mitigation suggestions only in passing, but the logical option is reducing greenhouse gas emissions and employing adaptive measures to protect against heat waves. It is a global responsibility, they remark. 

“Mitigation is the West’s burden, not ours. We have no choice here but to adapt,” says Wadid Erian, senior advisor on climate change adaptations and disaster risk reduction at the League of Arab States. 

Wadid, an independent commentator, says that the region needs to pool efforts into research; improving monitoring of the current climate and providing early warning systems. “So far, our body of knowledge into this region is very poor.” 

If the situation does turn desperate, Mahmoud Madani, a researcher from the Cairo-based Agricultural Research Centre not involved in the study, says that departure may be the only remaining solution. 

“Right now, Dubai is a bustling hub but perhaps in a century, it will be an abandoned, uninhabitable stretch of desert not unlike the Empty Quarter because of the [extreme] heat.” 

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