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What is climate change?


Snoqualmie Valley flood

What is climate change?

Greenhouse gases (GHG), are heat-trapping gases that naturally occur in the atmosphere and help regulate the temperature of the planet. Without naturally occurring GHGs , Earth’s average temperature would be near 0°F (or -18°C) instead of being a much warmer average temperature at 59°F (or 15°C).

Changes in climate are connected to changing concentrations of greenhouse gases (GHGs) in the atmosphere which trap heat and regulate the temperature of the planet. Some of the most important GHGs are carbon dioxide (CO2), methane (CH4), and water vapor. Human activities like driving cars, flying planes, and burning fossil fuels such as coal and oil, release excess GHGs into the earth’s atmosphere. This imbalance is causing global average temperatures to rise and ocean chemistry to change, resulting in unprecedented changes around the world , including here in King County .

There is overwhelming evidence that increases in carbon dioxide and other GHGs in the atmosphere are causing the climate to change and 97% of climate scientists have concluded that human activities are the reason for these changes. As a result, climate change is causing more heat waves, more extreme weather events, higher sea levels, major rainfall and storm pattern changes, disappearing glaciers, ocean acidification, and species extinction and range change. These environmental changes directly translate into economic, public health, and safety issues that affect people and communities in a variety of ways.

What is happening on a global scale?

Average temperature is rising.

Graph showing global temperature difference from 20th century average in degrees Fahrenheit. From 1900 through the late 1930s, temperature was below the mean. From then until 1976, temperature was both above and below the mean. After 1996, temperature has been above the mean and rising steadily. 2016 was the hottest year on record.

Carbon dioxide levels are the highest in the last 800,000+ years.

Atmospheric CO2 levels increased slightly since 10,000 years ago until pre-industrial times, then spiked from 208 parts per million to 406 parts per million between 1750 and 2017.

Rising CO2 levels are changing the chemistry of the oceans

Since the start of coal-powered industry in the 1750s, the acidity of ocean water has increased about 30%

What is happening on a global scale? Carbon dioxide (CO2) levels are the highest in the last 800,000+ years.
Greenhouse gases from traffic

Greenhouse gases in King County

King County’s overall goal is to reduce countywide GHG emissions, compared to a 2007 baseline, by 25 percent by 2020, 50 percent by 2030, and 80 percent by 2050.

Climate action, both to reduce GHG emissions and prepare for the impacts of climate change, is a long-standing and central priority for King County.

In 2015, the top sources of greenhouse gas (GHG) emissions in King County are from (1) fossil fuels used for transportation, and (2) energy used to heat, cool, and power homes and buildings. An additional significant source of GHG emissions is local consumption of goods and services, including the energy needed to produce, transport, use, and dispose of goods and services supporting county residents and businesses.

The pie chart below provides a breakdown of county-wide GHG emissions created by all residents, businesses, and government spending and consumption in 2015.

Where do greenhouse gases (GHG) come from in King County?

Most of the GHGs emitted in King County come from transportation and energy use. Purchased goods and services also have GHG emissions associated with them before they reach the consumer. The chart accounts for all GHGs created from goods and services, from production, to transportation, to sale, usage and disposal.

  • 25% - Goods such as clothing and electronics.
  • 22% - Transportation such as air and car travel.
  • 18% - Services such as health care.
  • 15% - Homes and buildings such as energy use for heating and lighting.
  • 13% - Food produces GHGs based on what, how and where it was grown.
  • 7% - Construction

Note: this chart shows GHGs associated with all residential, business and government spending and consumption based on data from 2015.

Pie chart graph of greenhouse gas (GHG) emissions