While the recent decline in energy prices is a good thing in that it has on balance raised the incomes of Americans, it does exacerbate the problem of energy overuse. The benefit of imposing carbon taxes is therefore enhanced.

on balance 是什么意思呢？是指“均衡的”吗？

查了一下解释，

on balance, after weighing up all the factors 可以理解为“在全衡所有因素”。但具体到这句话，应该怎么理解呢？

My comments:

The traditional weighing machine is a good place to start for us to understand what “on balance” means.

Balance is reached only when the weight on both ends are equal in quantity. Give to take a little on one side, the machine tilts.

Declining energy prices means, on balance, a raise in income for Americans because it works the same way. When energy prices were higher in the past, Americans had to spend more on gas at home and gasoline for the automobile, and that means having less to spend on other things.

Now, with less to spend on energy, everybody has more money on hand for everything else. Hence, lower energy prices, indirectly, raised incomes of Americans.

本文仅代表作者本人观点，与本网立场无关。欢迎大家讨论学术问题，尊重他人，禁止人身攻击和发布一切违反国家现行法律法规的内容。

About the author:

Zhang Xin（张欣） has been with China Daily since 1988, when he graduated from Beijing Foreign Studies University. Write him at: zhangxin@chinadaily.com.cn, or raise a question for potential use in a future column.

（作者 张欣，编辑 Helen）