Climate change is real. The stakes are high and the time is short. In Maryland, we just have to think about last week's sweltering weather to get a look into our future. In 50 years, it could be a rare summer day when temperatures in Maryland do not reach well into the 90s, with high humidity and warm nights. Most days would have code orange air quality or worse as the heat raises ozone levels, even as we are reducing air pollution. While we typically experience only two or three days when temperatures exceed 100 degrees, this would likely grow to 30 or more days, with life-threatening heat waves punctuated by intense downpours and flash flooding. These are just the patterns that climate scientists anticipate.

The science is clear: Climate change is occurring, is primarily due to human activities, and poses serious risks. Recent analysis reveals that 97 percent of the relevant scientific literature is consistent with this conclusion. Legitimate scientific debate continues over the rates and complex processes of human-caused climate change, but not its reality and its risks.

Heat waves; crop failures; drastic changes in our forests and fauna; and higher storm surges and inundation of coastal wetlands, communities and infrastructure are but some of the many consequences of climate change that Maryland will face. To avoid the worst of these consequences, the global emissions of greenhouse gases must be reduced sharply over the next 30 years.

More than four years ago, I was invited by the National Academy of Sciences to join a group of distinguished scientists, engineers and business leaders in an assessment of "America's climate choices." We were asked to develop reasoned choices about how the United States could limit the magnitude of climate change, adapt to the effects of unavoidable changes, advance the science and inform effective responses.

As we began, we felt that we might be too late in providing our advice. That summer, the House of Representatives passed the American Clean Energy and Security Act — with its cap-and-trade provisions — and it looked like we would reach global agreement on reducing the emission of heat-trapping, greenhouse gases at the end of 2009 in Copenhagen. Both efforts ultimately failed, and when the National Academy completed its five-volume report in 2011, America's climate choices remained yet to be made. Two years later, they still await our attention.

Fortunately, Maryland had already begun making its climate choices. Five months after assuming office in 2007, Gov. Martin O'Malley created the Maryland Climate Change Commission and charged it with developing an action plan to begin reducing greenhouse gas emissions to limit the magnitude of climate change and develop steps to adapt to the changes that lie ahead. He directed that Maryland's approach take advantage of the tremendous economic opportunities in the energy transition that would outweigh short-term costs.

The work of the Maryland Climate Change Commission led to the passage of the Greenhouse Gas Reduction Act in 2009. The act required the development of a plan to reduce Maryland's greenhouse gas emissions 25 percent by 2020 while increasing jobs and economic development. Working together with other recent state laws regulating carbon dioxide emissions from coal-burning power plants and auto emissions, requiring energy efficiency, and facilitating offshore wind and other renewable energy, the plan has already allowed Maryland to reduce its greenhouse gas emissions by 7 percent, placing our ambitious goal within reach.

Under the O'Malley administration, efforts have been instituted to track and reduce emissions from state government, including public universities and colleges. Planning has also been under way to adapt to changes in sea level, temperature and extreme events that accompany climate change. Such preparation includes diverse sectors, such as public health and safety, agriculture, public lands, transportation and Chesapeake Bay restoration. As part of this broad approach to being smart about climate, we are working to integrate climate literacy into new science and environmental standards in our schools to better equip our young citizens to deal with the choices that lie ahead.

While Maryland contributes just a small part of the world's greenhouse gas emissions, they are twice as large per capita as for the average European. Furthermore, as the United States' wealthiest, best-educated, and arguably most scientifically adept state, we have a special opportunity and a responsibility to lead the nation and the world by our own example and ingenuity. Quite simply: If we don't who will?

The Climate Action Plan for the nation that President Barack Obama announced this summer provides a needed boost for the state's efforts by cutting carbon pollution from power plants, building a 21st century transportation sector, and reducing emissions of greenhouse gases other than carbon dioxide. It also presents an opportunity for Maryland to exercise its leadership in showing how to build stronger and safer communities and infrastructure, protect our economy and natural resources, and use sound science.

Maryland's final plan, which Governor O'Malley will release at the Maryland Climate Change Summit on Thursday, is about better choices and better results for Maryland. It is about acting to limit climate change, being resilient to the changes that come, and educating young people so that they can make wise choices in the future. And it is gratifying to me that it has been about listening to science.

Donald F. Boesch is president of the University of Maryland Center for Environmental Science. His email is donboesch@umces.edu.