Carbon dioxide levels hitting historic high is the final wake-up call - The Week

At 415 ppm, carbon dioxide level is at highest ever in human history

A new 66 million-year history of carbon dioxide offers little comfort for today

Do high levels of CO2 in the past contradict the warming effect of CO2?

A Graphical History of Atmospheric CO2 Levels Over Time

415.26 parts per million: CO2 levels hit historic high

On Utqiagvik's edge, an observatory measures the gases that are warming the Arctic and the planet • Alaska Beacon

A Graphical History of Atmospheric CO2 Levels Over Time

Carbon dioxide now more than 50% higher than pre-industrial levels

The UN's dire warning about climate change is a wake-up call for everyone to take action - Upworthy

The carbon skyscraper - International Science Council

Climate Milestone: Earth's CO2 Level Passes 400 ppm

Time running out' says UN as CO2 levels hit record April high

Climate Milestone: Earth's CO2 Level Passes 400 ppm

Revealed: World's CO2 emissions set to rise by about 1 per cent to new record in 2023

climate change - What caused peak CO2 to rise, starting about 400,000 years ago? - Earth Science Stack Exchange

Carbon Dioxide Reaches Highest Recorded Levels In Human History

Carbon Dioxide (CO2)

Household CO2: What Causes High Carbon Dioxide Levels?

Is Carbon Dioxide Poisonous?

Carbon dioxide levels highest in human history

Researchers discover a way to tease oxygen molecules from carbon dioxide