Global Warming's Cost on Oceans: $2T a Year by 2100

Unless action is taken to protect them, damage to the world's oceans could reach $1.98 trillion annually by 2100, according to a study released today by the Stockholm Environment Institute. The principle culprit: climate change, which will cause rising sea levels, ocean acidification, marine pollution, species migrations, and cause tropical cyclones, Reuters reports. The report assumes temperatures will rise about 4 degrees Celsius over the century, but if governments can limit that to, say, 2.2 degrees, SEI says that would "save" almost $1.4 trillion of those damages.

Nitrogen-rich fertilizers and waste are playing a role as well, stripping the ocean of oxygen and creating what are called hypoxic dead zones. Oceanic experts have already found such zones in more than 500 places. The cost estimate includes $639 billion in lost tourism money, and another $458 billion caused by the fact that warming waters will be unable to absorb as much carbon dioxide. It doesn't include the cost of species that could be wiped out. (More climate change stories.)