Greenhouse gas levels in atmosphere hit new high in 2018, UN says

GENEVA, Switzerland — Greenhouse gases levels in the atmosphere, the main driver of climate change, hit a record high last year, the UN said Monday, calling for action to safeguard “the future welfare of mankind.”

“There is no sign of a slowdown, let alone a decline, in greenhouse gases concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change,” the head of the World Meteorological Organization Petteri Taalas said in a statement.

The WMO’s main annual Greenhouse Gas Bulletin listed the atmospheric concentration of CO₂ in 2018 at 407.8 parts per million, up from 405.5 parts per million (ppm) in 2017.

That increase was just above the annual average increase over the past decade.

World Meteorological Organization (WMO) secretary general Petteri Taalas shows the latest WMO Greenhouse Gas Bulletin during a press conference for the publishing of the annual Greenhouse Gas Bulletin on atmospheric concentrations of CO2 on November 25, 2019 in Geneva. (Fabrice Coffrini/AFP)

Concentrations of the other two main greenhouse gases, methane and nitrous oxide, also hit record levels in 2018, WMO said.

“This continuing long-term trend means that future generations will be confronted with increasingly severe impacts of climate change, including rising temperatures, more extreme weather, water stress, sea level rise and disruption to marine and land ecosystems,” WMO said.

Emissions are the main factor that determine the amount of greenhouse gas levels, but concentration rates are a measure of what remains after a series of complex interactions between atmosphere, biosphere, lithosphere, cryosphere and the oceans.

Pollution in the northern Israeli city of Haifa, April 15, 2015. (Basel Awidat/Flash90)

Roughly 25 percent of all emissions are currently absorbed by the oceans and biosphere — a term that accounts for all ecosystems on Earth.

The lithosphere is the solid, outer part of the Earth, while the cryosphere covers that part of the world covered by frozen water.

The UN’s Intergovernmental Panel on Climate Change (IPCC) has said that in order to keep warming below 1.5 degrees Celsius, net CO₂ emissions must be at net zero, meaning the amount being pumped into the atmosphere must equal the amount being removed, either though natural absorption or technological innovation.