Obviously, there are still many challenging issues related to climate change that Maryland's political leaders will have to tackle. It's one thing to set a goal, it's another to support programs that will achieve it, whether they involve tax credits, direct investments in renewable energy, conservation mandates or other hot-button issues. But the success of an effort launched in 2007 — when the year 2020 seemed a long way off — is reassuring: Maryland can dramatically reduce the amount of carbon dioxide and other pollutants in a reasonable time frame and without sacrificing livelihoods. Pay attention, Republican candidates for president, denying basic science and ignoring the threat of climate change is not the path to economic prosperity. Taking appropriate action and investing in the future is.