How did the opium trade affect the value of copper in China’s monetary system?

The opium trade significantly disrupted China’s bimetallic monetary system, which relied on a balance between copper cash used for daily transactions and silver used for large-scale business and tax payments.12

As the British opium trade expanded in the 19th century, the massive outflow of silver from China—driven by the need to pay for the smuggled drug—created a severe shortage of the metal within the Chinese economy. Because the exchange ratio between silver and copper was highly responsive to the supply of these metals, the drain of silver caused the value of copper to fall.3451

This devaluation of copper had widespread economic consequences, as it effectively increased the tax burden and cost of living for the common people who relied on copper cash for their daily needs. The resulting economic instability, coupled with the social disruption caused by widespread addiction, contributed to the weakening of the Qing dynasty during the 19th century.1534