A new study by associate agricultural and resource economics professor Joseph Shapiro finds that tariffs and other global trade barriers are lower for carbon-intensive products than greener ones, and that creates an "implicit subsidy to CO2 emissions" that amounts to $550 billion to $800 billion a year. This makes it harder to fight climate change, Professor Shapiro says. "The resulting change in global CO2 emissions has similar magnitude to the estimated effects of some of the world's largest actual or proposed climate change policies," he writes in the report. For more on this, see our press release at Berkeley News.