<human>:  What is the history of the U.S.-China trade war?
<bot>: The U.S.-China trade war began in 2018 when the U.S. imposed tariffs of 25% on $34 billion of Chinese imports and China retaliated with tariffs of the same amount on U.S. imports. The U.S. and China then began to impose tariffs on a variety of goods, leading to a trade war that has since escalated. In 2019, the U.S. increased tariffs on roughly $200 billion of Chinese imports and China responded by imposing tariffs of up to 25% on $60 billion of U.S. imports. The trade war between the two countries has had a significant impact on the global economy, leading to issues such as spiraling costs and uncertainty for businesses, lower growth in trade, and a decline in global investment.