Scientists in the United States have detected the highest levels of planet-warming carbon dioxide in Earth's atmosphere since record-keeping began.

Saturday morning's reading at the Mauna Loa Observatory in Hawaii was 415.26 parts per million (ppm) - the first time the daily baseline broke 415.  

"All of human history has been in a colder climate than now," said Wolfgang Lucht, from the Potsdam Institute for Climate Impact Research (PIK).  "Despite the Paris climate agreement, despite all the speeches and the protests - we are not seeing that we are bending the curve yet," he added.

The 2015 Paris Agreement calls on nations of the earth to stop the rise in Earth's temperature at "well below" 2 C degrees Celsius compared to pre-industrial levels, and 1.5 C degrees if possible.  Although there are some disagreements, many scientists say that a global CO2 average of 350 ppm would stave off runaway global warming.  Dr. Lucht believes it may have to go even lower.

"350 ppm is a precautionary value because some of the consequences of being above 400 may still be evolving," Lucht said.

But with little to no action being taken, expect the global temperature to rise even more and the rate of CO2 intrusion in the atmosphere to increase.

"The average growth rate is remaining on the high end. The increase from last year will probably be around three parts per million whereas the recent average has been 2.5 ppm," said Ralph Keeling, director of Scripps Institution of Oceanography's CO2 Program.  "Likely we're seeing the effect of mild El Nino conditions on top of ongoing fossil fuel use."