History

The Earth’s climate has changed many times during the planet’s history, with events ranging from ice ages to long periods of warmth. Historically, natural factors such as volcanic eruptions, changes in the Earth’s orbit, and the amount of energy released from the Sun have affected the Earth’s climate. Beginning late in the 18th century, human activities associated with the Industrial Revolution have also changed the composition of the atmosphere, and today increased human activity is influencing the Earth’s climate in such a way that scientists are calling for dramatic changes in our energy use and consumption.

Greenhouse Gases

For over the past 200 years, the burning of fossil fuels, such as coal and oil, and deforestation have caused the concentrations of heat-trapping "greenhouse gases" to increase significantly in our atmosphere. Carbon dioxide (CO2) is the most prevalent greenhouse gas. Greenhouse gases prevent heat from escaping to space, somewhat like the glass panels of a greenhouse.

Rising Temperatures

Naturally occurring greenhouse gases are necessary to life as we know it, because without them, the planet’s surface would be frigid and too cold for human life. But, as the concentrations of these gases continue to rapidly increase in the atmosphere, the Earth’s temperature is climbing above past levels. According to NOAA (National Oceanic and Atmospheric Administration) and NASA data, the Earth’s average surface temperature has increased by about 1.2 to 1.4F in the last 100 years. The eight warmest years on record (since 1850) have all occurred since 1998, with the warmest year being 2005. Most of the warming in recent decades is the result of human activities. Other aspects of the climate are also changing such as rainfall patterns, snow and ice cover, and sea level.

Scientists Predict

If greenhouse gases continue to increase, climate models predict that the average temperature at the Earth’s surface could increase from 3.2 to 7.2F above 1990 levels by the end of this century. Scientists are certain that human activities are changing the composition of the atmosphere, and that increasing the concentration of greenhouse gases will change the planet’s climate. But they are not sure about how much it will change, at what rate it will change, or what the exact effects will be.

Insurance Policy

Whether or not dramatic changes will come next year, in ten years or in one hundred, we believe the best thing we can do is to put into effect an "insurance policy" against the threat of climate change for all of earth’s inhabitants. By conserving energy and decreasing our carbon emissions today, we can leave our planet in the same relative condition it has been in for present and future generations to enjoy.

Climate Change Q&A

What has already been affected by climate change?

• The Earth has already warmed 1.3°F over the past 100 years, and it is projected to increase by an additional 3.2-7.2°F over the next 100.
• There is a dramatic increase in the number of forest fires in the West and Southwest of the United States, and insect outbreaks have fueled those fires.
• The number and severity of tropical storms and hurricanes in the North Atlantic have increased in the past 100 years and this is likely due to warming.
• Unprecedented heat waves are on the rise in the United States —the last 9 years are among the hottest 25 on record.
• A severe drought has affected the southwestern United States during the past nine years, and is beginning to affect the Southeast as well.
• The once permanent Polar Ice Cap is contracting at a rate of 9% each decade.
• Polar Bears, Walrus, whales and seals are changing their feeding and migration patterns.

What is the difference between climate change and global warming?

The term climate change is often used interchangeably with the term global warming, but according to the National Academy of Sciences, "the phrase ‘climate change’ is growing in preferred use to ‘global warming’ because it helps convey that there are other changes in addition to rising temperatures." Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period. Global warming is an average increase in the temperature of the atmosphere near the Earth’s surface and in the troposphere, which can contribute to changes in global climate patterns.

What is the greenhouse effect?

The greenhouse effect is a natural phenomenon that helps regulate the Earth’s temperature. Greenhouse gases (e.g., carbon dioxide, methane, nitrous oxide, chlorofluorocarbons) act like an insulating blanket, trapping solar energy that would otherwise escape into space. Without this natural "greenhouse effect," temperatures would be about 60ºF lower than they are now, and life as we know it today would not be possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have enhanced the natural greenhouse effect, causing the Earth’s average temperature to rise.

What can we do about it?

Virtually everything we do uses energy, from driving cars, to using electricity, to growing food. Today, the vast majority of this energy comes from nonrenewable, carbon-intensive resources. An easy and inexpensive way to slow climate change is to conserve at home and at work. In addition to conservation, we can take advantage of energy-efficient electronics and appliances. Finally, we can support renewable, clean energy through solar, wind and more.