Mohammad Saleh Nishwar, 79, has sold merchandise at Souq Waqif in Doha, Qatar, for more than 60 years. His family-owned store, about the size of a parking space, hasn’t budged in almost 100 years. Reconstruction projects have protected its cultural merit, as part of the oldest trading area in Qatar. Across the street, soaring temples of trade, banking, hospitality and governance are rising from the desert sands, fertilized by seemingly endless fossil fuels. Aside from considerable oil reserves, Qatar has proved 900 trillion cubic feet of natural gas, the largest single gas field under the earth’s crust.