In 2018, global average concentrations of the greenhouse gas, which is a byproduct of burning fossil fuels, reached 407.8 parts per million, which means for every 1 million molecules of gas in the atmosphere, nearly 408 were carbon dioxide. This level is up from the global average of 405.5 parts per million in 2017. The findings follow a trend that shows the planet is continuing to warm at an alarming pace.

“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,” WMO Secretary-General Petteri Taalas said in a statement.

Carbon dioxide traps heat from the sun and can linger in the atmosphere for centuries. High levels of the greenhouse gas are associated with higher global temperatures and other effects of climate change, such as melting polar ice and rising seas.