This month, I want to focus on a big-ticket action to reduce my carbon emissions by one whole ton going into summer. I’m going to look at the role money plays in climate change, and what I can do with my money to make a difference. This week I give some background about money and emissions:

Banks and climate change

This issue hit home for me back in 2012 when I read “Global warming’s terrifying new math,” a piece by Bill McKibben in Rolling Stone magazine. He gives three numbers that he says are key to understanding the challenge of climate change.

2 degrees Celsius is the maximum amount of warming scientists thought the planet could take at the time without causing major disruptions for humans. Now scientists think that number is 1.5 degrees Celsius, a goal echoed in the Paris climate agreement.

565 gigatons is our global carbon budget, how much carbon dioxide we can emit by midcentury to stay under the 2 degree threshold. At the time the article was written, our carbon budget was projected to be spent within 16 years: before 2030. A global energy report by the International Energy Agency last year shows we’re still on the path McKibben described seven years ago, with energy use on the rise.

2,795 gigatons is the amount of carbon in the proven reserves of oil and gas companies. That means that energy companies currently have five more carbon reserves on the books than we can burn without devastating consequences. This means that either these companies need to be massively devalued, or it’s already game over.

This article was sobering for me, and I’ve taught it to several classes since first reading it, because it shows the scale of change we need, and that for us as a species to survive, we basically have to tell the world’s richest, most profitable companies that they suddenly lost virtually all of their value. If these companies are ever forced to keep their huge reserves in the ground, the $20 TRILLION dollars would become “stranded assets” – the huge red losses would turn these companies from cash cows to bankrupt. This is the economic argument used by those seeking divestment—or dis-investment—from fossil fuels: that such investments are too risky in the long-term. Of course, the moral argument for divestment is that we shouldn’t be making money by trashing our children’s future. But somehow that argument doesn’t work so well when money’s on the line.

This poses a huge financial problem, but not just for fossil fuel companies. Because virtually everyone with a bank account or financial investment is involved. And that’s why I am challenging myself to change my bank account this month. So let’s take a closer look.

How does my money contribute to climate change?

Let’s say you open a bank account and put in $1,000 (or €1,000). Depending on your country’s reserve requirements, your bank can now lend money dramatically exceeding your deposit. A fairly conservative reserve requirement – the amount of cash on hand a bank has to have for every loan it takes out – is 10%. So your $1,000 checking account lets the bank invest or lend out $10,000.

What does your bank do with this $10,000? Do you know? Banks can offer personal or commercial loans, but they also use other investment instruments, from government bonds to stocks and mutual funds.

And if you put your $1,000 in an investment account like a mutual fund, or a pension, you might be able to see where that money is going. Some investment products are even based on certain values – such as not investing in weapons manufacturers or fossil fuels.

The divestment campaign started in part by 350.org in response to McKibben’s article seeks to harness the power of money to nip climate change in the bud. The idea here is that, if fossil fuel companies can’t fund their activities, they will have to stop extracting sooner. This is not just an abstract argument. Alexander Sammon wrote last year in the New Republic that the billions of dollars given to bail out U.S. banks in 2008 were largely responsible for the boom in fracking. Banks sought to put these funds into “safe” investments, with much going to an industry that had flatlined. Loans in the oil and gas sectors almost tripled thanks to bailout money, causing a ripple effect that Sammon links to about 5% of total world oil production.

So where you put your money can make a big difference in whether you’re helping the climate. That’s why I’m going to change my bank account next week.

What’s giving me hope this week

I thought I’d stick with the money theme this week. I got some outraged text messages from my mother that U.S. Treasury Secretary Steve Mnuchin basically confirmed his agency’s delay of the $20 redesign that would replace Andrew Jackson with Harriet Tubman on the front of the $20. These texts made me really angry, because I saw it as playing into a passive partisanship that I find extremely troubling. However you feel about Donald Trump, Republicans, democracy, whatever, is completely confirmed by this news. Trump is a racist! Trump is a patriot! And the world continues to burn, but you can nurture your safe sense of outrage that doesn’t require you to actually do anything.

But after getting these depressing text messages, I chanced across an article about an artist named Dano Wall, who created a Harriet Tubman stamp that he hopes people will use to change the currency until the official redesign comes along. Reading this filled my heart with such joy – it didn’t just make my day, but it made my week. This isn’t surprising coming from a podcast in which I act as a guinea pig for climate action, but I think it is SO IMPORTANT to not just complain about what we don’t like, but get out and do something about it. So I love, love, love that Dano Wall took a bit of news that angered him and found a creative, positive, DIY solution. If I had regular access to $20 bills, you better believe I’d be stamping away my days. So thanks, Dano – you’re giving me hope this week.