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Eco Library


Climate Change

Climate Change

A Changing Pace

Weather happens hour by hour, day by day—it’s a thunderstorm, a heat wave, a windy afternoon. Taken as averages over decades and centuries, those patterns of precipitation, temperature, and wind for a given region comprise our climate.

For as long as Earth has existed, such climate conditions at specific sites have shifted over long periods of time. However, within the last century, climatic shifts—extreme weather of all sorts, including droughts, higher temperatures, and higher sea levels—have accelerated at an unprecedented rate. The result: climate change.

The Role of CO2

Scientific evidence points to rising levels of carbon dioxide (CO2) and other greenhouse gases as the most significant contributor to climate change. While some greenhouse gas emissions are naturally occurring, the exponential increase in recent decades, generated in part by human activities—think burning fossil fuels and deforestation—interferes with the planet’s atmosphere. Like a blanket, CO2 traps solar heat within the atmosphere, shifting how much moisture evaporates from the oceans, how much falls as snow or rain and in what parts of the world, and the rate at which ice on the polar caps melts.

It’s All in the Numbers

Scientists first recognized the possibility of human influence on the climate system around the ’60s—the 1760s, that is, the beginning of the Industrial Revolution. While climatologists began documenting subtle shifts around then, the most extreme evidence of climate change has accumulated since the mid-1950s. In the United States, torrential rainfall, wildfires, drought, heat waves, and floods have all become more intense and more frequent.

In 2010, the National Research Council called on the United States to act immediately to reduce greenhouse gas emissions and develop a national plan to adapt to the inevitable results of a changing climate.

What It Means

As climate changes further, scientists forecast that precipitation trends will intensify, with the northern United States becoming wetter, while states in the South—especially in the West—will experience even more intense droughts. On the coasts, plan for increasingly severe hurricanes with flooding and storm surges. Nationwide, scientists forecast that the average U.S. temperature will rise by 4 to 11 degrees Fahrenheit. In Southern states, that could translate to 150 days every year when the mercury rises above 90 degrees Fahrenheit.

Such shifts have effects on the food supply as farmers respond to increasingly erratic temperatures and rainfall patterns during the growing season. Consider, for example, the shifting date of peak cherry bloom in our nation’s capital—now five days earlier, on average, than it was in the 1920s.

Other aspects of climate change have more profound consequences for wildlife and humans. For example, polar bears in Canada’s Hudson Bay have diminished access to the ice from which they usually hunt—threatening the species with extinction. Ducks, geese, and other water birds are shifting their migration patterns in response to extreme droughts and floods. Humans, too, are feeling the effects of extreme weather. Populations of mosquitoes, ticks, and other disease carriers are shifting, altering the risk of things like West Nile virus and Lyme disease in the United States. Some areas of the world are experiencing intense heat and widespread drought, while others are suffering from torrential rains and frequent flooding—which affects local agriculture and public health.

Plan of Action

The small choices we make every day can influence global emissions. Look for ways to reduce consumption whenever possible—for example, choose high-efficiency appliances and light bulbs with the Environmental Protection Agency’s ENERGY STAR label. When contemplating a new purchase, embrace the mantra “reduce, reuse, recycle” to minimize what’s hauled to your community’s landfill. Extend the concept to the kitchen by turning food and lawn waste into compost; while landfills generate greenhouses gases from rotting waste, composting turns organic waste into nutrient-rich soil. On the road, opt to walk, bike, or use public transportation whenever possible. And if you must drive, consider a carpool, and practice regular maintenance to optimize your vehicle’s fuel efficiency.