For comparison’s sake, the world’s GDP is $70 trillion. The findings assume that 50 gigatons of methane would be released over the course of 10 to 20 years in a warming pulse.
Some climate scientists disagree with the underlying assumption. Gavin Schmidt has taken to Twitter to argue that 50 gigatons is an excessive estimate; prior warming periods didn’t show similarly large releases of methane.
On the other hand, climate scientist Dr. Michael Mann tells TakePart: “The precise magnitude [of methane] is an object of valid debate, but the possibility of a substantial release cannot be dismissed out of hand.” Climate modelers have underestimated Greenland sheet ice and Arctic sea ice melt, so the estimate is not outside the realm of possibility.
Very large numbers make us sit up and take notice, but they’re also hard to grasp. What is climate change currently costing even without that warming pulse? A NRDC report estimates that American taxpayers, through the federal government, paid $100 billion in 2012 — more than the cost of education or transportation. (And that doesn’t include what state and local governments, insurers, or private citizens paid.) Mann estimates the global cost at $1.4 trillion per year in coastal damage, droughts, fires, floods and hurricanes.
We know that Mayor Bloomberg’s proposal to armor New York City to protect against the next Sandy has a $20 billion price tag. No similar grand proposal has been made for other great cities of the East Coast — Boston, Washington, D.C., or Charleston. No similar proposal has been made for Midwestern cities facing floods, or Southwestern cities, where wildfire season now starts July 1 and ends June 30.
And what of Miami? It contributed $263 billion to gross domestic product in 2010, according to the Bureau of Economic Advisors. Caught between rising seas to the east and the Everglades to the west, the city is doomed to drown.
Abandoning Miami means not only moving or abandoning the businesses who create its gross domestic product, but walking away from its pricey real estate, its roads, hospitals, schools and infrastructure. The cost of relocating its people needs to be calculated both in dollars and in heartbreak. But if you ask people to estimate the cost of abandoning Miami, you get blank stares. It’s as if the language to ask the question hasn’t been invented yet.
“It is not difficult to envision much larger costs, [i.e., $60 trillion] given the potential larger and more abrupt warming [the more abrupt the warming, the more costly it is to try to adapt] that the authors calculate,” says Mann. And it’s not difficult to imagine that there are costs we haven’t even begun to imagine. And when you multiply those costs, city after city after city, suddenly $60 trillion becomes a very realistic and frightening number.
