Carbon dioxide levels in atmosphere breach threshold
Levels of CO2 in the atmosphere have surged past the 400 parts per million breaching an important threshold.
The benchmark was broken globally for the first time in recorded history in 2015 but according to the World Meteorological Organisation (WMO), 2016 will likely be the first full year to exceed the mark. The levels are unlikely to dip below the benchmark for “many generation.”
While human emissions of CO2 remained fairly static between 2014 and 2015, the onset of a strong El Niño weather phenomenon caused a spike in levels of the gas in the atmosphere.
El Niño created drought conditions in tropical regions and vegetation was less able to absorb CO2.
While the El Niño factor has now disappeared, the human impact on climate change has not, the WMO warns. There were also extra emissions from fires, sparked by the drier conditions.
All these conditions helped push the growth in the levels of CO2 in the atmosphere above the average for the last ten years the World Meteorological Organisation says in it’s annual Greenhouse Gas Bulletin.
The high threshold breaking levels were recorded at the atmospheric monitoring station in Mauna Loa, Hawaii.
The last time CO2 was regularly above 400ppm was three to five million years ago, say experts. Prior to 1800 atmospheric levels were around 280ppm, according to the US National Oceanic And Atmospheric Administration (Noaa).
“The year 2015 ushered in a new era of optimism and climate action with the Paris climate change agreement,” said WMO Secretary-General Petteri Taalas.
“But it will also make history as marking a new era of climate change reality with record high greenhouse gas concentrations.”
The report also details the growth in other greenhouse gases, including methane and nitrous oxide.
In 2015, levels of methane were 2.5 times greater than in the pre-industrial era, while nitrous oxide was 1.2 times above the historic measure. The study also points to the impact of these increased concentrations of warming gases on the world’s climate.
Between 1990 and 2015 there was a 37% increase in radiative forcing or warming effect, caused by a build up of these substances, from industrial, agricultural and domestic activities.
The WMO welcomes new initiatives like the global agreement to phase out HFC gases agreed recently in Rwanda, but argues that nations must retain their focus on cutting CO2.
“Without tackling CO2 emissions, we cannot tackle climate change and keep temperature increases to below 2 degrees C above the pre-industrial era,” said Petteri Taalas.
“It is therefore of the utmost importance that the Paris Agreement does indeed enter into force well ahead of schedule on 4 November and that we fast-track its implementation.”
Around 200 nations who signed the Paris climate agreement will meet in Morocco in November to decide on the next steps forward.