Back in May, we reached an important milestone in our impact on the environment, and hardly anyone heard about it. Carbon dioxide levels reached 400 parts per million (for every million molecules in the atmosphere, 400 were carbon dioxide) as an average for the entire day. This is the first time this has happened in at least three million years, long before homo sapiens walked the Earth. Essentially, this means that we are not doing much to slow climate change and reduce greenhouse gas emissions. The time to invest in alternative energy sources and sharply reduce our fossil fuel emissions was yesterday.
“Indirect measurements suggest that the last time the carbon dioxide level was this high was at least three million years ago, during an epoch called the Pliocene. Geological research shows that the climate then was far warmer than today, the world’s ice caps were smaller, and the sea level might have been as much as 60 or 80 feet higher. Experts fear that humanity may be precipitating a return to such conditions — except this time, billions of people are in harm’s way.”