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”嗎？

查了一下解釋，

on balance, after weighing up all the factors 可以理解為“在全衡所有因素”。但具體到這句話，應該怎么理解呢？

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.

本文僅代表作者本人觀點，與本網立場無關。歡迎大家討論學術問題，尊重他人，禁止人身攻擊和發布一切違反國家現行法律法規的內容。

About the author:

Zhang Xin（張欣） 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 張欣，編輯 Helen）