Red Alarm: Carbon dioxide levels hit record in 2016

Concentrations of carbon dioxide surged at a record breaking speed in 2016, according to the annual Greenhouse Gas bulletin compiled by the World Meteorological Organization. The Geneva-based organization said that levels of the heat-trapping gas CO2 in the atmosphere are the highest in in 800,000 years. "The abrupt changes in the atmosphere witnessed in the past 70 years are without precedent," WMO said in a statement.

Scientists have reliable data on carbon dioxide concentration spanning approximately 800,000 years, and researchers estimate the last time the planet had a comparable concentration of carbon dioxide was 3 to 5 million years ago, during the Pliocene epoch, when the global temperature was up to 3°C warmer and due to melting ice sheets, sea level was about 66 feet higher than it is today.

The bulletin attributes the increase in CO2 levels to the El Niño event and greenhouse gas emissions from human activities, including "growing population, intensified agricultural practices, increases in land use and deforestation, industrialization, and associated energy use from fossil fuel sources" since the "industrial era, beginning in 1750."

While emissions represent the full amount of carbon dioxide released into the atmosphere, the measured concentrations focus on what remains in the atmosphere "after the complex system of interactions between the atmosphere, biosphere, cryosphere, and the oceans." As carbon sinks, the oceans and biosphere each take up about a quarter of total CO2 emissions.

The bulletin comes ahead of a separate U.N. Environment Emissions Gap Report, which will be released Tuesday and analyzes the projected effectiveness of various nations' policies to reduce greenhouse gas emissions through 2030. The two reports will serve as "a scientific base for decision-making" at the COP23 climate talks, according to WMO.

"The numbers don't lie," said Erik Solheim, head of U.N. Environment. "We are still emitting far too much and this needs to be reversed. The last few years have seen enormous uptake of renewable energy, but we must now redouble our efforts to ensure these new low-carbon technologies are able to thrive."

"We have many of the solutions already to address this challenge," Solheim concluded. "What we need now is global political will and a new sense of urgency."