Unbalancing Act

The Battle for Balance

Getting out of balance often causes serious problems—for us and for our planet. In fact, respecting the Earth's need for balance is essential to our own well-being.


Scientists estimate that several million to 100 million species of plants, animals, and other organisms share the Earth. This huge ran shows how much we still have to learn.

These are examples of the latest counts for known species:

  • Vertebrate animals: 53,000
  • Invertebrate animals: 1.2 million
  • Insects: 950,000
  • Plants: 270,000
  • Bacteria and other microbes: countless millions

By any measure, we've identified only a sliver of the species that share our world.

click to enlarge
Source: SNZP, Stephanie Garnett

Most undiscovered species probably live in rainforests or coral reefs—perhaps the most endangered habitats on Earth.

We're always trying to balance things: schoolwork, activities, social life, chores, and all the rest. It's not easy. Tackling one thing often means ignoring another. If that goes on too long, it can threaten a person's physical and emotional health. Picture yourself on a seesaw just after the other person has leapt off suddenly. You've probably had times when you felt exactly like that.

Just like us, our Earth needs balance. And that balance, scientists warn, is precisely what human actions are undermining. In the past few centuries, we've managed to change the world in amazing ways: highways link whole continents, forests disappear, dams tame mighty rivers, crops bloom in deserts, and buildings scrape the sky. All that is wonderful in its way. But these changes—and many more—have altered the planet's balance in unfathomable ways.


Once the trees come down, what will happen to this land? Source: Washington Department of Fish and Wildlife Once the trees come down, what will happen to this land?
Source: Washington Department of Fish & Wildlife



Here are just a few human actions—and their effects:

  • Agriculture: High-tech farming sometimes treats the land like dirt, which can lead to massive erosion as well as runoff that poisons water supplies.
  • Deforestation: Needing lumber or land for farms and towns, we've cleared vast areas of forest.
  • Habitat Fragmentation: Countless animals have wound up with only small, isolated pockets of habitat. That can make it almost impossible for them to find
    food and mates.
  • Sprawl: Growing populations need space. To get it, we're paving over more and more of the natural world.
  • Water Control: Damming rivers and creating artificial lakes greatly impact the surrounding land—and people.


Watch the forest disappear as roads and houses fragment the land. It's urban sprawl in action.
Source: John Rozum, NEMO



Maintaining Earth's balance is tricky business. So many forces affect the environment that pinpointing causes and effects is incredibly difficult.

click to enlarge image
Changes in the climate or habitat lead to loss of biodiversity.
Source: United Nations Environment Programme

Scientists have found, however, that one good measure of balance is whether we are maintaining biodiversity. That's the full range of plants and animals living in an area—and the relationships among them.

Loss of biodiversity can take a toll on human health. For example, disease-carrying mice may increase in number when their predators become scarce. One of the best-known examples of what happens when biodiversity declines is the spread of Lyme disease.


New York City recently saved several billion dollars. How? By protecting farmland in its Catskill Mountains watershed area. As rainwater runs through the creeks, streams, and wetlands of this protected land, natural processes clean the water efficiently. As a result, the city gets a steady flow of good drinking water. And taxpayers don't have to pay for expensive equipment to clean their water.

That's just one example of how humans benefit from "intact functioning ecosytems"—or undisturbed ecosystems. Researchers demonstrated recently that the world saves $33 trillion a year, thanks to nature's "ecosystem services." Typical services include flood control and storm protection (from wetlands), fish harvests and related jobs (from coral reefs), and fertile soil for farming (from grasslands).


Trees and air quality around the country. Source: American Forests Source: American Forests


Redwood Forest. Source: National Park Service Redwood Forest
Source: National Park Service

Other studies have found that an undisturbed ecosystem is worth nearly twice as much—in terms of the value of products it can produce—than the same amount of developed land. The United States Department of Agriculture calculated that by removing pollutants from city air, trees also cut our health costs. Trees are nature's efficient air-cleaning machines.

In fairy tales, walking into the woods often means trouble. Forests are painted as dark, wild places filled with unseen dangers. Unexplored wilderness can be frightening. But it also promotes our well-being in ways we are only beginning to understand.


health_iconHow does biodiversity loss help spread Lyme disease?

science_iconWhat can other cultures teach us about biodiversity?


Unbalancing Act Home back_unbalancenext_unbalance How does modern agriculture cultivate food for thought?

Additional information