By our inability to prevent a global 2+°C warming, by virtue of there being very nearly 400 parts per million CO₂ despite our scientists’ constant warnings to do whatever it takes to reduce that number to at least 350, we’re going to cost ourselves a hell of a lot of money. Both in the short term and in the long term.

Firstly, the Arctic is thawing. Within the Arctic is a time-bomb of methane gas that’s gonna cost us almost as much as the global economy.

“The global impact of a warming Arctic is an economic time-bomb,” said Gail Whiteman, an author of the report and professor of sustainability, management and climate change at the Rotterdam School of Management, part of Erasmus University.

“In the absence of climate-change mitigation measures, the model calculates that it would increase mean global climate impacts by $60 trillion,” said Chris Hope, a reader in policy modeling at the Cambridge Judge Business School, part of the University of Cambridge.

That approaches the value of the global economy, which was around $70 trillion last year.

The methane bomb is a one time event though, as it has a significantly different impact life span of 20-ish years, compared to CO₂‘s 5 years in the atmosphere til it gets either taken up by biological processes or the ocean. The problem with CO₂ is that while any individual molecule stays in the atmosphere for a few years, it also might return to the atmosphere after a stint in the ocean or in the trees. The individual molecules stick around for thousands of years compared to methane’s 20-ish, and we’re pumping out twice as much CO₂ as the planet can apparently sink per year.

Plus, the repercussions of more CO₂ in the oceans is acidification, which kills coral and marine life and could destroy the entire fishing industry and any culture that relies on it for food.

Global warming doesn’t just mean it’ll get warm and stay warm — it means there’s more energy in the system, so you have wilder weather swings. You’ll therefore see superstorms in all weather: tornadoes and hurricanes, blizzards and thunderstorms, floods and droughts. The more energy, the bigger and more frequent the energetic releases. And we all know how much damage each of those events can do, money-wise.

All of this, compared to the costs of finding a less carbon-heavy way of feeding ourselves, finding a less carbon-heavy way of powering our electrical gadgets and climate control systems and personal conveyance, and industry. It’s possible to beat this issue without all of us turning into cave-dwelling survival nuts, but we need to fix a lot of processes that are well and truly entrenched — and as far as I can tell, they’re only entrenched at this point because certain people are still making money off the carbon economy. A carbon economy the American government subsidizes heavily by giving huge kickbacks to the oil industry. How much is THAT costing us? How much would carbon really cost if not for the invisible hand of the marketplace sticking a heavy thumb on those scales?

When some climate denialist says it’s too expensive to do anything about CO₂ emissions — show them these costs. The cost argument evaporates when you take into account how much inaction will cost.