Thanks to evolution, our bodies have powerful ways to ward off illness and infection and enable us to live long and healthy lives. Why, then, do health costs continue to climb at unsustainable and frightening rates?

Hydraulic fracturing requires massive amounts of water. Disposing of the toxic wastewater, as well as accidental spills, can contaminate drinking water and harm human health.

Doing all we can to combat climate change comes with numerous benefits, from reducing pollution and associated health care costs to strengthening and diversifying the economy by shifting to renewable energy, among other measures.

If America wants to retain its position as a global power, its president must listen to the people and show strong leadership at this turning point in human history.

The human brain now holds the key to our future. We have to recall the image of the planet from outer space: a single entity in which air, water, and continents are interconnected. That is our home.

If we have any hope of finding ways for seven billion people to live well on planet with finite resources, we have to learn to use our resources efficiently. Plastic bags are neither efficient nor environmentally friendly.

Most North Americans know that human-caused global warming is real, even if political leaders don't always reflect or act on that knowledge.

If America wants to retain its position as a global power, its president must listen to the people and show strong leadership at this turning point in human history.

The medical literature tells us that the most effective ways to reduce the risk of heart disease, cancer, stroke, diabetes, Alzheimer's, and many more problems are through healthy diet and exercise. Our bodies have evolved to move, yet we now use the energy in oil instead of muscles to do our work.

If we pollute the air, water and soil that keep us alive and well, and destroy the biodiversity that allows natural systems to function, no amount of money will save us.