Carbon dioxide – the greenhouse gas most responsible for global warming – reached an all-time high in Earth's atmosphere in 2018, the World Meteorological Organization (WMO) announced Monday.
“There is no sign of a slowdown, let alone a decline, in greenhouse gas concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change,” WMO Secretary-General Petteri Taalas said in a statement.
Globally averaged concentrations of carbon dioxide reached 407.8 parts per million in 2018, up from 405.5 parts per million in 2017, the WMO said.
The burning of fossil fuels such as coal, oil and gas releases greenhouse gases such as carbon dioxide and methane into Earth's atmosphere and oceans. The extra greenhouse gases have caused the planet's temperatures to rise to levels that cannot be explained by natural factors, scientists report.
In the past 20 years, the world's temperature has risen about two-thirds of a degree Fahrenheit, the National Oceanic and Atmospheric Administration said.
In a statement, the WMO said this continuing long-term trend of rising carbon dioxide 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.
“It is worth recalling that the last time the Earth experienced a comparable concentration of carbon dioxide was 3-5 million years ago," Taalas said. Back then, he said the Earth's temperature was as much as 5 degrees warmer and sea levels were as much as 65 feet higher than they are now.
Carbon dioxide remains in the atmosphere for centuries and in the oceans for even longer.
Carbon dioxide wasn't the only greenhouse gas to surge in 2018: Concentrations of methane and nitrous oxide also surged by higher amounts than they had during the past decade, the WMO said.
This article originally appeared on USA TODAY: Carbon dioxide reaches record high in Earth's atmosphere