903. Record High Atmospheric Greenhouse Gas Concentrations in 2022

On November 15, the World Meteorological Organization (WMO) announced that atmospheric greenhouse gas concentrations for the year 2022 have reached an all-time high.

In 2022, atmospheric CO2 concentrations exceeded 50% of pre-industrial levels. Although the rate of CO2 increase slowed slightly from the previous year, the WMO attributes this to short-term fluctuations in the carbon cycle. Nevertheless, greenhouse gas emissions continue to escalate along with industrial activity. In particular, the Earth has not experienced such CO2 concentrations for 3-5 million years, a period marked by temperatures 2-3°C higher and sea levels 10-20 meters higher.

The concentration of methane in the atmosphere has also increased. Forty percent of methane emissions are of natural origin (such as wetlands and termites), while 60% are attributed to human activities (including ruminants, rice paddies, fossil fuel extraction, landfills, biomass burning, etc.). The growth rate for 2021-2022 was slightly lower than that for 2020-2021, but remained significantly higher than the average growth rate over the past decade.

Nitrous oxide concentrations, which have a strong greenhouse effect and also deplete the ozone layer, recorded the highest growth rate in history between 2021 and 2022. It is estimated that 60% of nitrous oxide emissions come from natural sources such as oceans and soil, while the remaining 40% come from anthropogenic sources such as biomass burning, fertilizer use and various other industrial activities.

The WMO Secretary-General expressed concern that current efforts to curb greenhouse gas emissions are insufficient. Despite long-standing warnings from the scientific community, the Secretary-General called for accelerated reductions in fossil fuel consumption.

The food system was highlighted as a significant contributor to emissions, implicated in anthropogenic releases of methane and nitrous oxide. To mitigate greenhouse gas emissions and provide nutritious food for the world's population, a collective reassessment of dietary habits is urged. This includes minimizing food loss and waste while actively promoting scientific and technological innovation.

Contributor: IIYAMA Miyuki (Information Program)