Energy Task Force

Clean, renewable energy refers to electricity or heat produced from clean, renewable sources of power such as the sun, wind, water, and organic waste. Nuclear power, though it does not emit greenhouse gases, is not considered clean and renewable because of the safety concerns, radiation pollution and waste storage problems, as well as the fact that nuclear power does not replenish itself. Currently the US produces most of its energy with sources known as "dirty energy" - fossil fuels and nuclear power.

Greenhouse gas emissions are gases that trap heat in the Earth's atmosphere. Without greenhouse gases the average global temperature would go from 59 degrees Fahrenheit to 0 degrees Fahrenheit. The most notable greenhouse gases are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), halocarbons that contain fluorine such as hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆).

Greenhouse gases are emitted from a variety of natural and anthropogenic (human) sources. Carbon dioxide has the greatest effect on climate change because of its abundance. CO₂ is emitted from the burning of fossil fuels (coal, oil, and natural gas), solid waste incineration and wood burning. Only a small proportion of CO₂ emissions come from natural sources, such as plant decay, volcanic eruptions and animal respiration.

Human-related activities account for approximately 70% of global methane emissions, while natural sources account for the other 30%. The major anthropogenic sources of methane in the US are waste decomposition in landfills, domesticated livestock and the production and transport of natural gas and coal.

Anthropogenic emissions of nitrous oxide are primarily generated by agricultural soil management, mobile and stationary sources of fossil fuel combustion, adipic acid production and nitric acid production. Natural sources of N₂O account for twice as many of the emissions as anthropogenic sources.

Scientists know for certain that human activities are changing the composition of Earth's atmosphere. Increasing levels of greenhouse gases, like carbon dioxide, in the atmosphere since pre-industrial times have been well documented. There is no doubt this atmospheric buildup of carbon dioxide and other greenhouse gases is largely the result of human activities.

It's well accepted by scientists that greenhouse gases trap heat in the Earth's atmosphere and tend to warm the planet. By increasing the levels of greenhouse gases in the atmosphere, human activities are strengthening Earth's natural greenhouse effect. The key greenhouse gases emitted by human activities remain in the atmosphere for periods ranging from decades to centuries.

A warming trend of about 1°F has been recorded since the late 19th century. Warming has occurred in both the northern and southern hemispheres, and over the oceans. Confirmation of 20th century global warming is further substantiated by melting glaciers, decreased snow cover in the northern hemisphere and even warming below ground.

As atmospheric levels of greenhouse gases continue to rise, scientists estimate average global temperatures will continue to rise as a result. By how much and how fast remain uncertain. IPCC projects further global warming of 2.2-10°F by the year 2100. This range results from uncertainties in greenhouse gas emissions, the possible cooling effects of atmospheric particles such as sulfates and the climate's response to changes in the atmosphere.

This rise in global temperature will lead to climate change. There is uncertainty as to how exactly how the climate will change and what the effects will be. The IPCC predicts that impacts of GHG emissions include an increase in the frequency and severity of floods, drought and blizzards, a rise in sea-level affecting coastal areas and changes in precipitation patterns that would impact water supply and food production.

Scientists have identified that our health, agriculture, water resources, forests, wildlife and coastal areas are vulnerable to the changes that global warming may bring. But projecting what the exact impacts will be over the 21st century remains very difficult. This is especially true when one asks how a local region will be affected.

We all must take responsibility for our individual actions. There are simple steps you can incorporate into your daily life that will make a real impact reducing greenhouse gas emissions and mitigating climate change. To learn more, visit the Energy Task Force's resources page.