Climate Change > What is climate change?

What is climate change?

"Climate change" is the rapid changing of climates around the world. Much of the problem is attributed to burning fossil fuels (coal, oil and gas) and deforestation. The heat-trapping blanket of greenhouse gases in the atmosphere causes global temperatures to rise. This trapped energy can also cause potentially significant changes in the timing and length of the seasons as well as the amount and frequency of precipitation. In Washington State, climate change is already disrupting our environment, economy and communities. We can help slow it down, but we must take action now.

In February 2007, the Intergovernmental Panel on Climate Change reported to the United Nations that "warming of the climate system is unequivocal" and that it is more than 90% likely that the accelerated warming of the past 50-60 years is due to human contributions.

What is global warming?

"Global warming" refers to rising global temperatures as a result of increasing greenhouse gases in the atmosphere caused by human activities. As global temperatures rise, this causes climate to change. A warmer Earth will lead to

• changes in rainfall patterns,
• rising sea levels, and
• a wide range of impacts on plants, wildlife, and humans.

What are greenhouse gases?

The major greenhouse gases covered by the Kyoto Protocol are carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons. These are the greenhouse gases that scientists say are contributing to climate change. Water vapor is a naturally occurring greenhouse gas, but human activity does not directly affect its concentrations except at very localized sites.

What is the greenhouse effect?

The greenhouse effect occurs as a result of greenhouse gases trapping the heat from the sun and keeping it close to the earth. Anyone who has parked his or her car in the sun for a few hours on a summer day has experienced something like the greenhouse effect. The sunlight pours through the glass windows and heats up the inside of the car, and the glass doesn't let the heat back out again. The heat can't escape because the sides, floor, and roof of the car are closed. This is similar to what is happening to the earth.

Source: http://www.climatesolutions.org/

Isn't the greenhouse effect just a natural occurrence?

The earth has a natural greenhouse effect that keeps it about 60 degrees warmer than it would be otherwise. This enables us to live comfortably on earth. But human activities, mainly the burning of fossil fuels, have greatly added to the natural greenhouse effect. Increases in global temperatures over the last century correspond with increased industrialization. Loss of forest trees to absorb carbon dioxide (a key greenhouse gas) is also a major contributing factor.

What are the causes of climate change and global warming?

The greenhouse gases that cause global warming come from many sources, but the main source is the burning of fossil fuels. We use coal, oil, and natural gas to generate electricity, heat our homes, power our factories, and run our cars.

Changing land use patterns through agriculture and deforestation also contribute greatly. Trees and other plants use carbon dioxide and give off oxygen. When trees are cut down for development, agriculture, and other purposes, they not only can't use up the carbon dioxide in the air as they usually do, but they actually release it when they decay or are burned.

The United States is the world's largest source of greenhouse gases. The U.S. has about four percent of the world's population, but contributes about 30 percent of the carbon emissions.

Fifty percent of Puget Sound's regional greenhouse gas contributions are transportation related. Most of the growth in overall CO₂ emissions in Washington State is from the transportation or electricity generation sectors.

There are actions we can take now to reduce greenhouse gas contributions, for we are all daily energy managers.

Is climate change really happening?

Yes. Climate change is already occurring and is caused by human actions. That fact is agreed upon by 100% of the peer-reviewed scientific studies over the last 10 years (928 articles as of 11/16/06). In contrast, 53% of the 636 climate articles over the last 14 years in the popular press (NY Times, Washington Post, LA Times and Wall Street Journal) quoted scientifically discredited views of skeptics. Unfortunately, this "balance" of differing views reported within the media does not reflect the very strong agreement among scientists - that human-caused climate change is indeed a fact, without doubt.

According to the National Academy of Sciences, the earth's surface temperature has risen by about one degree Fahrenheit in the past century, with accelerated warming during the past two decades.

There is new and stronger evidence that most of the warming over the last 50 years is due to human activities. Ice cores taken from deep in ancient ice of Antarctica show that carbon dioxide levels are higher now than at any time in the past 650,000 years. More carbon dioxide in the atmosphere means warming temperatures.

The above figure shows the global annual temperature change since 1880 in the land-ocean temperature index. Source: NASA Goddard Institute for Space Studies. (January 11, 2008)

Many indications of global warming have been occurring with more and more frequency.

• Mountain glaciers have retreated worldwide in the last few decades.
• Ice caps in the Artic and Antarctic are thinning and melting rapidly, contributing to rising sea levels.
• Sea level has risen about four to ten inches in the last century.
• Precipitation has increased at higher latitudes and decreased in the tropics.
• Intense rainstorms and snowstorms have become about ten percent more frequent in the U.S. and southern Canada during the 20th and 21st centuries.
• The number of intense cyclone-type storms per winter has been increasing in recent years, as have hurricanes.
• Major storms since the 1970's in both the Atlantic and Pacific oceans have increased in duration and intensity by about 50 percent, according to MIT researchers.

Why is climate change a concern?

Scientists predict that warming of the oceans and melting of glaciers due to global warming and climate change could cause sea levels to rise between six and 38 inches by the year 2100. Floods and drought could become more frequent and more severe. Loss of snow pack would reduce water available in Washington rivers for people, farms and fish.

These and other changes, such as changes in precipitation and soil moisture, could affect many things important to human life and all life around us, including:

• natural ecosystems
• agriculture
• human health
• hydropower
• forestry
• water resources
• energy use, and
• transportation.

See Climate Change Effects in Washington State.