Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Home » Mauna Loa

Mauna Loa

Outside of Mauna Loa observatory in Hawaii overlooking mountains

Rise of carbon dioxide unabated

Atmospheric carbon dioxide measured at Mauna Loa Observatory reached a seasonal peak of 417.1 parts per million for 2020 in May, the highest monthly reading ever recorded. Monthly CO2 values at Mauna Loa first breached the 400 ppm threshold in 2014, and are now at levels not experienced by the atmosphere in several million years.

Scroll to Top

Popup Call to Action

A prompt with more information on your call to action.