The Environmental Protection Agency released a report, Clmate Change in the United States: Benefits of Global Action, that looks at the economic effects of keeping global average temperature below an increase of 2 degrees Celsius above the pre-industrial average. The EPA's new report estimates that if all the countries of world cooperated to meet this goal the avoided costs of climate change damage in the U.S. in 2100 would amount to about $1.5 trillion per year.
The report takes into account things like damage to water quality, bridges, roads, drainage systems, coastal property inundation, drought, flooding, agricultural, forestry and fishery stresses, and carbon storage. Taking the worst-case scenario highest figures for each, those all together amount to losses of about $55 billion in 2100.
The lion's share of unmitigated climate change stems from the costs of premature death resulting from air pollution at $930 billion and higher temperatures at $200 billion, as well as lost work hours due to excessive heat, $110 billion, and the costs of adapting to water shortages at at worst-case $180 billion. (To get the premature death costs, the EPA is valuing each life at about $16 million in 2100 dollars.) Sounds like a lot, right?
Assume that the current $17.7 trillion U.S. economy grows at an average rate of 2 percent per year from now until 2100. GDP in 2015 dollars would then be $95.3 trillion. That means that annual climate change losses and adaptation costs of $1.5 trillion would amount to 1.6 percent of the economy. Notionally speaking, GDP would be only be $93.8 trillion instead of $95.3 trillion. In other words, due to the ravages of climate change, average per capita GDP for 450 million Americans would be only $208,000 instead of $212,000. For reference, current U.S. per capita GDP is just above $53,000.