Met Office: Atmospheric CO2 now hitting 50% higher than pre-industrial levels - Carbon Brief
co2 levels in atmosphere at their highest in 800,000 years | World Economic Forum
File:Global Atmospheric CO2 Historic.jpg - Wikimedia Commons
The Keeling Curve | National Geographic Society
A Graphical History of Atmospheric CO2 Levels Over Time | Earth.Org
Climate Change: Atmospheric Carbon Dioxide | NOAA Climate.gov
Atmospheric concentration of Carbon Dioxide (ppm) — European Environment Agency
Climate Change: Atmospheric Carbon Dioxide | NOAA Climate.gov
Carbon dioxide in Earth's atmosphere - Wikipedia
10,000 Years of Carbon Dioxide - Berkeley Earth
CO2 Levels: Current & Historic Atmospheric Carbon Dioxide / Global Temperature Graph & Widget
Carbon Dioxide | Vital Signs – Climate Change: Vital Signs of the Planet
How reliable are CO2 measurements?
Do high levels of CO2 in the past contradict the warming effect of CO2?
Carbon dioxide now more than 50% higher than pre-industrial levels | National Oceanic and Atmospheric Administration
CO2 since 1800
CO2 Past
Carbon Dioxide Through Time | EARTH 103: Earth in the Future
CO2: Past, Present, & Future – Time Scavengers
Ancient Deepsea Shells Reveal 66 Million Years Of Carbon Dioxide Levels - Texas A&M Today
CO2: Past, Present, & Future – Time Scavengers
Carbon Dioxide Through Time | EARTH 103: Earth in the Future
A Graphical History of Atmospheric CO2 Levels Over Time | Earth.Org
