By Sharon Newman-Ehrlich

It is a rare opportunity to watch an elected official perceive the severity of a societal dilemma. It's even rarer to see him start off strong, concede to his critics, and then return to a firm stance.

Sen. Bob Casey (D., Pa.) was downright hawkish on climate change in early 2009, when he spoke of global warming's "untold consequences on the world's economy and population" on the Senate floor. Only a few months later, he was one of six Democrats to join a Republican effort to prevent a carbon dioxide cap-and-trade program from being included in that year's budget resolution.

For the next few years, Casey straddled Pennsylvania's political forces, acknowledging the effects of climate change while trying to protect the commonwealth's fossil-fuel industry. Since then Pennsylvanians have witnessed superstorms, countless weather records, and several years recorded as the "hottest ever" at the time. By 2050, the state is projecting that Philadelphia will have the current climate of Richmond, Va.

We can now count on Casey to defend the Environmental Protection Agency's first-ever limit on carbon dioxide pollution from existing power plants in Congress. The week before Thanksgiving, the senator voted against a resolution to dissolve the carbon dioxide standards. While the measure passed 52-46, it was not enough to override President Obama's veto.

I was lucky enough to meet with the senator's staff in Washington the week before, while the EPA oversaw the final set of public hearings on the Clean Power Plan. The senator recognizes that climate change is, above all else, a public-health issue. Rising temperatures affect the way air and water move around the planet, causing droughts, floods, and/or storms in different conditions.

The population within the Delaware River Basin will increase from 8.5 million to 11 million by 2050, according to a report by the University of Pennsylvania, putting a growing population in an expanding flood plain with several industrial pollution sources (with more being proposed). New York City's 8.5 million people draw their water supply from the Delaware's headwaters, and with rising sea levels on the East Coast, the ocean is literally moving up the Delaware. The "salt line" is currently four miles north of its November average, which is perfectly safe but not to be ignored.

A warmer ocean also allows for increased rain clouds. Slumping trade winds in an El Niño year allowed Hurricane Sandra to become the strongest storm ever recorded in the eastern Pacific Ocean after Thanksgiving.

Johns Hopkins University recently concluded that Philly's energy grid is "increasingly susceptible" to stronger storms. This is a time to decentralize our power sector, creating smaller, dispersed sources that don't force millions to rely on single, large generation units. Duke Energy just installed a 2-megawatt storage battery at a retired coal plant in Ohio that both absorbs and distributes electricity depending on current needs. As we get better at conserving electricity, flexibility within the power grid is becoming more important.

How much power will we need this winter? PJM Interconnection, a regional transmission organization, estimates that 13 states from New Jersey to Illinois will experience a 132,000-megawatt demand this winter with a 178,000-megawatt capacity, and much of that comes from Pennsylvania. One-third of the electricity generated in the commonwealth is exported to other states, exposing Pennsylvanians to more pollution than is needed to power their homes.

While Casey was attempting to protect Pennsylvania's economy in 2009 by preventing the imposition of a carbon cap-and-trade system, it is now apparent that without adequate precautions against rising temperatures and increased rain events, the economy will suffer no matter how strong the fossil-fuel industry is.

Agriculture remains the state's largest industry. Outdoor recreation is another pillar of our economy, generating $21.5 billion in consumer spending while directly supporting 219,000 jobs. These industries will be the first victims of climate change, along with our state's roads, bridges, and transit systems, all of which received D grades from the American Society of Civil Engineers in 2014.

These are not the concerns of an overreacting environmentalist. This year will be recorded as the hottest ever globally, and 2011 through 2015 will be recorded as the hottest five-year period. Pennsylvania's economic livelihood depends on pollution reduction and climate-change preparedness.

Sharon Newman-Ehrlich taught science in the Philadelphia School District for 26 years and is the founder of the Community Science and Technology Education Project (CSTEP). teach0697@gmail.com