Tortoise Senior Portfolio Manager Rob Thummel in CNBC

Natural gas prices have already doubled this year. A hot summer could push them even higher

U.S. natural gas prices more than doubled since the start of the year, and this summer’s air-conditioning season could send them soaring by at least another 25%.

In the futures market, gas prices rose 4% Tuesday as hot spring weather in the Southern U.S. pressured a market that has already been concerned about tight supplies. The warmer weather is forecast to continue across the region.

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