I saw seven bald eagles circling 200 feet over the forest canopy. Seven! In the low-angle sunlight of a late afternoon in mid-March, their heads and tails were luminous white beacons. I hadn’t spotted an eagle for months, and I considered them a promise that a harsh winter was waning.

But these magnificent seven were also a sign of something else. Though I grew up in northeastern Minnesota, where bald eagle sightings are now routine outside of deep winter, I didn’t catch a glimpse of one until I was 18 years old, in August 1969. A friend and I were on a canoe trip in the Boundary Waters Canoe Area Wilderness, paddling across Knife Lake on the Ontario border, when we noticed an eagle perched on the limb of an old white pine. We chattered with excitement. Bald eagles had become so rare in the Lower 48 as to be almost mythical. We saw them on coins and currency, on banners and crests, in books and on TV — everywhere but in the sky. The protections of the Endangered Species Act and the banning of the pesticide DDT rescued them from the brink of collapse.

I remember another event from 1969. That summer a sensational news item shocked the nation: The Cuyahoga River in Cleveland had burst into flame. A combustible blend of debris and petrochemical waste ignited, damaging a bridge. A burning river? Actually, the preceding century had seen nine fires on the heavily polluted stream, and at least two others — the Buffalo River in New York and the Rouge River in Michigan — had also spawned contaminant-fueled fires in flowing water. The bizarre incident is credited with helping to spur passage of the Clean Water Act and the Great Lakes Water Quality Agreement, and also with the creation of the Environmental Protection Agency, signed into existence in 1970 by President Richard Nixon. Today, the Cuyahoga is significantly improved, supporting 44 species of fish on a stretch where the number was precisely zero in 1969. The river remains one of 43 Great Lakes Areas of Concern, but during dry spells when urban runoff is low, it’s officially sanctioned as suitable for recreation.

These cases remind me of a simple declarative sentence from Steven Pinker’s recent book, “Enlightenment Now: The Case for Reason, Science, Humanism, and Progress,” which serves as a summary of his thesis: “Problems are solvable.”

Obvious? Not so much. It’s characteristic of human minds that we tend to focus on the negative. One reason may be that taking the dim view had survival value for our ancestors, such as, is that longish shape partially concealed in the bushes a stick of firewood or a cobra? Survivors bet on the cobra. Call it enlightened cynicism — and pass it on. Similarly, the enduring shibboleth of broadcast news, “if it bleeds it leads,” reflects that we are more reliably intrigued by bad news than by good. Wars, riots, mass shootings, tornadoes (and flaming rivers) have more potential to change our lives than peace, tranquillity and the good deeds of Girl Scouts — or at least that’s what we’re conditioned to believe. Given a body of information that encompasses both sunlight and shadow, most of us most of the time will gravitate to the dark side.

That tendency is the currency of Facebook and social media in general, resident in the algorithms used to manipulate users. As tech pioneer and Silicon Valley guru Jaron Lanier wrote, “Negative emotions such as fear and anger well up more easily and dwell in us longer than positive ones. … Fight or flight responses occur in seconds, while it can take hours to relax. This is true in real life, but it is even more true in the flattened light of algorithms.” He posits that “negative feedback turns out to be the bargain feedback, the best choice for business, so it appears more often in social media.”

Our by-the-minute, 24/7 information sources are so biased to the negative that the challenges of the 21st century — climate change, terrorism, nuclear arms (still), species extinction, resurgences of authoritarianism, to name a few — seem insurmountable to any person who’s paying attention. And that prompts the crucial question: In a milieu saturated with data, what do you pay attention to? An old friend of mine used to parse the question by asking in turn, “What difference will it make a hundred years from now?” The scale was exaggerated, but the point was clear: There’s a lot of trivial noise in the world. However, there are also many important signals, and the key is to differentiate between the two.

In 1960, the systems theorist and prominent futurist Herman Kahn said in reference to nuclear weapons, “I have a firm belief that unless we have more serious and sober thought on various aspects of the strategic problem … we are not going to reach the year 2000 — maybe not even the year 1965 — without a cataclysm.” When I graduated from high school in 1969, I was convinced that my future would be bleak and brief. All-out atomic war seemed inevitable, a commonplace dread stoked by countless warnings like Kahn’s. Truly, it would be difficult to exaggerate the ambient fatalism, but a half-century later we’re still here. Have we been lucky? Yes, but we also acted to reduce the number of warheads, banned weapons testing, lessened Cold War tensions and slowed proliferation of nuclear capability. A threat remains, but the “buttons” haven’t been pushed.

It’s wise to pay attention to a warning, but a mistake to treat it as a given outcome. For example, many dire alarms have been raised over genetically modified organisms — GMOs — but seem based upon amorphous cultural fears (“mad scientists”), and ignorance of biology and ecology. Certainly, caution is a virtue when manipulating genomes, but the fact is that humans have been genetically altering (often carelessly) domestic plants and animals for about 10,000 years. Your dog is a GMO. It’s just that now it can be done more quickly and purposefully with technology than with breeding programs. GMO crops, the unfairly vilified “frankenfoods,” are likely the only way we’ll be able to feed the 9.8 billion humans we’ll have around in 2050. “Natural” organic farming on a large scale requires significantly more land per pound of food grown, demanding that more forests, wetlands and prairie be put under cultivation, thereby destroying even more habitat and perhaps leading to starvation for many. That doesn’t sound sustainable or “green” to me. Stewart Brand, whose environmentalist credentials are impeccable, wrote, “I daresay the environmental movement has done more harm with its opposition to genetic engineering than with any other thing we’ve been wrong about. We’ve starved people, hindered science, hurt the natural environment, and denied our own practitioners a crucial tool.”

So the mission of a responsible adult is: Research, think, then act. No one can know about, care about or fix everything, so choose your cause(s) and pick your battle(s). Problems are legion and will always tax us, but our past demonstrates they are also solvable. Discern the signals in the noise, separate the warnings from the ground truths and cultivate an acquaintance with history. You may then trust your capacity to understand, judge and make a difference. (Hint: Online petitions count for almost nothing; if it seems too easy, it probably is.)

Seeing seven bald eagles in a blue Minnesota sky was pure, unmitigated information, a strong signal that delivered the unambiguous message that we acted and the eagles came back. When I saw them, I whooped and thrust up my arms, realizing the future may not be as bleak as our human nature seduces us to imagine. So long as we are willing to work for closely considered, clear-eyed change.

Peter M. Leschak, of Side Lake, Minn., is the author of “Ghosts of the Fireground” and other books.