We only have a few decades to deal with climate change. If humanity fails to cut back dramatically on carbon emissions by 2050, according to an alarming new UN report, our planet may warm past the point of our ability to fix the problem.
Given global dependence on oil, gas, and coal, weaning every economy from fossil fuels to save Mother Earth won't come easy or cheap. Fortunately, there's a big pot of money available to avert a climate catastrophe.
Accessing that money, however, requires cutting back on a different set of pollutants — the huge cache of weapons the world continues to produce.
Europe has trimmed its military spending and the Pentagon budget is leveling off. Yet other regions are burning through more cash to wage or gear up for war than they used to.
Military outlays are rising the most in Africa and the Middle East. And Asia surpassed Europe last year for the first time in terms of overall military spending.
The United States still faces no competition for its distinction as the world's military spending champion. The Pentagon's $640 billion tab amounted to more than a third of the $1.75 trillion in global military spending the Stockholm International Peace Research Institute itemized for 2013.
What does worldwide military excess have to do with today's reliance on fossil fuels? Instead of investing in ways to slow global warming and adapt to a changing climate, too many nations are pouring money into weapons in an ongoing fight over the dwindling resources we haven't quite used up yet.
There's still time to pivot in a new direction. One big step governments, industries, and investors must take is to quadruple the money they're pumping into sustainable alternatives to oil, gas, and coal.
Those investments now total about $250 billion a year. While that may sound like a lot of solar panels and wind turbines, the United Nations says it's not enough. It will take a "clean trillion" every year between now and 2050 keep the world livable, the International Energy Agency estimates.
Yes, the private sector needs to play a role in building a fossil-free global economy. So do governments, which possess the power to tax carbon-intensive energy. That's certainly one good way to generate revenue for meeting the climate challenge while creating incentives to increase efficiency.
But world leaders can't really fight climate change unless they slash military spending.
As climate writer and activist Bill McKibben says, do the math. Just shrinking the global military-industrial complex by 25 percent would free up $437.5 billion a year. Given the security challenges climate change poses, this makes perfect sense.
The head of the U.S. fleet in the Pacific has identified climate change as the biggest threat facing the region. The Pentagon is devoting considerable resources to studying rising temperatures as "threat multipliers" bound to stoke competition for resources, make humanitarian disasters more common, and increase political instability.
Battleships and fighter jets can't defeat the threat of a melting ice cap or rising sea levels. It will take mountains of money to reduce our carbon emissions while maintaining a modern economy.
It may help to think about climate change as "getting embroiled in a war that lasts 100 years" without any obvious exit strategies, as retired Brigadier General Chris King puts it.
"You can see in military history, when they don't have fixed durations, that's when you're most likely to not win," warns King, the dean of academics at the U.S. Army Command and General Staff College in Fort Leavenworth, Kansas.
Unless every nation ramps down military spending, we'll all lose the next big war over the fate of the Earth without even firing a shot.