Investors in GM (NYSE: GM) have hoped that overseas sales would help offset the tremendous weakness of the car company's U.S. operations. When it comes to Europe, no such luck. That leaves fewer and fewer places for the firm to make money.

According to Reuters, "General Motors Corp's head of European operations said rising oil prices, high commodity costs and the strength of the euro could drive European sales down to levels not seen in decades." Sales in China and Latin America are pretty much all that is left to push up margins.

It is fair to ask how much of this is GM's fault. The answer is a large amount of it. The core reason for the sales slump in Europe is the same as in the US: Gas prices are up. Fewer people may be buying cars, but when they are, they want fuel-efficient models. Firms like VW and Toyota (NYSE: TM) are sitting there waiting to whisk those customers into their showrooms.

Buicks and Cadillacs may sell well in China were the cost of gas is underwritten by the government. But GM's problems in Europe could have been, to some extent, avoided. Mile-per-gallon and miles-per-meter may sound different, but they really aren't.

Douglas A. McIntyre is an editor at 247wallst.com.