Pointing to increased consumer interest in the environment, Mastercard Inc. launched a calculator Monday that provides credit card users a look into how much carbon emissions their purchases have generated. The company says it’s the first attempt to use consumers’ real purchase data to calculate their impact on the environment.  Since credit card data shows where but not what a customer has purchased, the tool won’t be 100% precise. (Mastercard knows, for instance, that you’ve made a purchase at a grocery store, but not the exact items in your order.) Calculations instead will be broken down by purchase category, using technology developed by Swedish fintech company Doconomy. The calculator is part of a broader effort Mastercard says it launched last year to capitalize on increased consumer interest in the environment and sustainability. Business leaders and environmental experts alike continue to sound the alarm about our role in climate change and the costs of inaction. Carbon dioxide is one of the primary drivers of climate change, and the resulting effect on the environment could amount to $1.7 trillion in global economic damage annually by 2025 if the current trend continues. “Companies, consumers and communities must work together to make the significant changes needed to effectively address climate change," said Jorn Lambert, Mastercard’s chief digital officer, in a statement. “The Mastercard Carbon Calculator informs consumers about the carbon footprint of their purchases, so that they can make more mindful spending decisions and contribute to forest restoration.” For example, Mastercard’s calculator will allow people to see things like the number of trees required to absorb the amount of carbon dioxide generated by a purchase, to give context about each consumer’s environmental impact. The tool will be available across the Mastercard network, so banks using Mastercard’s system for their credit cards can integrate the calculator into their mobile apps. Mastercard said that it intends to plant 100 million trees as part of its Priceless Planet Coalition, and it has set up a system for its customers to donate or use their loyalty points to contribute to the cause. Trees can remove carbon dioxide from the atmosphere and may help mitigate climate change. First Hawaiian Bank is one credit card issuer on board, with plans to allow its Mastercard cardholders to redeem rewards points in exchange for a new tree planted on their behalf.  An online financial firm, Aspiration, announced a similar program last month. Its new environmentally friendly card—part of the Mastercard network—exchanges a planted tree for each swipe of the card. Users of the new card, called Aspiration Zero, who attain carbon-neutral status each month can also earn cash-back rewards.