Greenhouse gases

We're working to reduce greenhouse gas emissions to protect Washington's economy and environment from the effects of climate change. We track emission sources and require large facilities and state agencies to report their emissions. We publish an inventory of greenhouse gas emissions in Washington every two years.

What are greenhouse gases?

The term "greenhouse gases," or GHGs, covers a wide variety of gases that, once they are released into the atmosphere, trap the sun’s heat. When the sun’s energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and trapped in the lower atmosphere, heating the Earth. This is called the "greenhouse effect."

Up to a point, the greenhouse effect helps keep the Earth at a temperature suitable for life. As more greenhouse gases are pumped into the atmosphere, however, the temperature increases and there's a risk of creating feedback effects that could make the Earth warmer still.

Naturally occuring greenhouse gases:

  • Water vapor (H2O)
  • Ozone (O3)
  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Nitrous oxide (N2O)

Human-made greenhouse gases:

  • Chlorofluorocarbons (CFCs)
  • Hydrofluorocarbons (HFCs)
  • Perfluorocarbons (PFCs)
  • Sulfur hexafluoride (SF6)

Atmospheric concentrations of both the natural and human-made greenhouse gases have been rising over the last few centuries due to the Industrial Revolution, population growth, and our dependence on fossil fuels. 

Greenhouse gas emission limits

In 2020, the Washington Legislature set new greenhouse gas emission limits in order to combat climate change. Under the law, the state is required to reduce emissions levels:

  • 2020 - reduce to 1990 levels. ​
  • ​2030 - 45% below 1990 levels.
  • 2040 - 70% below 1990 levels.
  • 2050 - 95% below 1990 levels and achieve net zero emissions.

Reporting and inventories

We require facilities and state agencies to report their emissions and publish an inventory of Washington's greenhouse gases to help us design policies to reduce greenhouse gas emissions and track progress.