Or even a huge, thirsty one: the entire globe, for instance, which in many regions is painfully parched.

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Such explanations likely would have been of cold comfort to the crowd of hot, thirsty, bedraggled people outside the convention center, even if they could have heard them.

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If all goes well, it may even fulfil an old dream to irrigate swathes of farmland in northern Sudan, while sending electricity to run the thirsty air-conditioners of Khartoum.

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