BBCNews.com, Nov. 22, 2018
Concentrations of key gases in the atmosphere that are driving up global temperatures reached a new high in 2017.
In their annual greenhouse gas bulletin, the World Meteorological Organization (WMO) says there is no sign of reversal in this rising trend. Carbon dioxide levels reached 405 parts per million (ppm) in 2017, a level not seen in 3-5 million years.
Researchers also note the resurgence of a banned gas called CFC-11.
What are concentrations?
Concentrations differ from emissions in that they represent what remains in the atmosphere after some of the gases are absorbed by the seas, land and trees.
Since 1990 the warming impact of these long lived gases on the climate has increased by 41%.
How does the latest data compare to previous years?
2017 continues the rise in concentrations of CO2 which are now 46% greater than the levels in the atmosphere before the industrial revolution.
The increase from 2016 to 2017 was smaller than the rise from 2015 to 2016, but is close to the average growth rate seen over the last decade.
The scientists at the WMO believe that the amount of CO2 in the atmosphere right now hasn't been seen in a long, long time.
"The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, when the temperature was 2-3C warmer and sea level was 10-20 metres higher than now," said WMO Secretary-General Petteri Taalas.
"Every fraction of a degree of global warming matters, and so does every part per million of greenhouse gases."
Will this new study have any impact?
The scientists behind it certainly hope so. They believe that their analysis needs to be seen alongside the recent IPCC 1.5C report which warned that the world needed to be essentially carbon neutral by 2050.
The WMO bulletin comes out just a week or so before climate negotiators begin at the COP24 meeting in Katowice, Poland, where countries will discuss putting the Paris climate agreement into practice and increasing their ambitions when it comes to cutting warming gases.
"The new IPCC Special Report on Global Warming of 1.5C shows that deep and rapid reductions of emissions of carbon dioxide and other greenhouse gases will be needed in all sectors of society and the economy," said IPCC Chair Hoesung Lee.
The WMO greenhouse gas bulletin, showing a continuing rising trend in concentrations of greenhouse gases, underlines just how urgent these emissions reductions are."