Nov 14 (Reuters) - Energy firms are using a chunk of their bumper quarterly profits from surging natural gas and fuel prices to reward shareholders with higher dividends and share buybacks. The top 25 North American oil and gas companies by market capital posted a combined profit of $70.04 billion for the quarter ended Sept. 30, 186.3% higher than a year earlier, according to Refinitiv data. However, the record profits have renewed calls for a windfall tax, especially as sky-rocketing prices have fueled inflation around the globe.