Climate threatsEconomic damage of carbon emissions costlier than earlier thought

The data used to calculate the damage that an additional ton of carbon dioxide has on the global economy has long relied on outdated science. Recent updates modeled by the University of California, Davis and Purdue University raise the calculations of those costs significantly and change the outlook on climate change from a positive for agriculture to a negative.

When the most recent science is brought to bear, one of the major models used to calculate the social cost of carbon (SCC) moves the figure to $19.70, an increase of 129 percent.

Purdue notes that state and federal government agencies often use the social cost of carbon in cost-benefit analyses for projects that stand to add carbon dioxide to the atmosphere. It is meant to calculate the damage a ton of additional carbon dioxide will have on society and the economy, including agricultural productivity, human health, property damage due to flooding and energy costs.

Three integrated assessment models are widely used for the analysis of environmental policy, but only one of these, the FUND model, explicitly focuses on damages to the agricultural sector. However, these calculations of damages in agriculture currently rely on very old data.

“The underlying studies date back to publications in the 1990s, but it really dates back to science from the 1980s,” said Thomas Hertel, Purdue distinguished professor of agricultural economics, whose findings were published in Nature Communications. “It was optimistic on the benefits to agriculture from rising temperatures.”

Early studies suggested that moderate amounts of warming would be positive for agricultural crops, and since an increase in carbon dioxide can improve plant health, adding more to the atmosphere was considered beneficial. The SCC for agriculture calculated using the FUND model puts these damages at -$2.70, a negative number indicating overall benefits from CO₂ emissions.