For nearly four years, the Trump Administration has denied climate science. That all could change in January. If so, Americans need to move past climate science and embrace the next step: climate math.

For more than 10 years, Business Forward has organized briefings on climate change, clean energy, and energy security. Tens of thousands of business leaders have participated in our climate conference call briefings, local roundtables, Washington fly-ins, or media trainings. They tend to talk about how severe weather is affecting commodity prices, their supply chains, their plants and equipment, or demand for their products. Restaurant owners talk about food prices. Farmers talk about crop yields. Auto suppliers talk about shipping delays. And brokers worry about whether anyone will be able to afford insurance for their beach houses.

Invariably, someone asks, “Can we afford to fix it?” Invariably, the rest of the room says, “We can’t afford to ignore it.” The table agrees we need to do something, but it rarely has enough data to prioritize what could be done.

To prioritize, we must understand which activities generate the most greenhouse gas pollution and how much reducing that activity might cost. We need apples-to-apples ROI comparisons of, say, electrifying our auto fleets property law reforms that could slow deforestation. If you want to understand options for stopping climate change and have time for only one book, we recommend The Drawdown Review, a comprehensive, accessible, and relatable look at the three-piece climate puzzle.

“Drawdown” is the future point in time when levels of greenhouse gases in the atmosphere stop climbing and start to decline steadily. You can achieve this by (1) reducing carbon emissions into the atmosphere; (2) supporting and enhancing the natural “climate sinks” that absorb carbon dioxide (like our oceans and forests); and (3) helping society achieve broader transformations (like improving healthcare in developing countries, which can encourage families there to have fewer children). Each potential solution has a cost and an impact. By lining them up, side by side, The Drawdown Review helps you understand how to save our planet “quickly, safely, and equitably.”

You may be spending your free time this month helping elect candidates who want to do something about climate change. If so, carry on and good luck. But if you have some free time, consider learning a little climate math.