Heat-trapping greenhouse gases in the atmosphere have reached record new levels, says the World Meteorological Organisation’s annual Greenhouse Gas Bulletin (GHG Bulletin), released on November 25. Globally averaged concentrations of carbon dioxide (CO2) reached a new high of 407.8 parts per million (ppm) in 2018, up from 405.5 ppm in 2017, the GHG Bulletin reported. This is 147 per cent of the pre-industrial level in 1750.
The increase in CO2 from 2017 to 2018, according to the GHG Bulletin, was very close to that observed from 2016 to 2017 and just above the average over the last decade. Global levels of CO2 had crossed the symbolic and significant 400 ppm benchmark in 2015 itself. CO2 remains in the atmosphere for centuries and in the oceans for even longer. While CO2 is the main long-lived GHG (LLGHG) in the atmosphere related to human activity, concentrations of methane and nitrous oxide, the other important LLGHGs, also surged by higher amounts than during the past decade, according to observations from the Global Atmosphere Watch (GAW) network that includes stations in the remote Arctic, mountain areas and tropical islands.
Since 1990, there has been a 43 per cent increase in the total radiative forcing—the warming effect on the climate—by the LLGHGs. CO2 accounts for about 80 per cent of this, says the GHG Bulletin, quoting figures from the United States National Oceanic and Atmospheric Administration (NOAA).
“There is no sign of a slowdown, let alone a decline, in GHG concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change,” said World Meteorological Organisation (WMO) Secretary-General Petteri Taalas. “We need to translate the commitments into action and increase the level of ambition for the sake of the future welfare of the mankind,” he said.
“It is worth recalling that the last time the earth experienced a comparable concentration of CO2 was 3-5 million years ago. Back then, the temperature was 2-3°C warmer, and the sea level was 10-20 metres higher than now,” Taalas added. The GHG Bulletin reports on atmospheric concentrations of greenhouse gases. Emissions represent what goes into the atmosphere. Concentrations represent what remains in the atmosphere after interactions between the atmosphere, biosphere, lithosphere, cryosphere and the oceans. About a quarter of the total emissions is absorbed by the oceans and another quarter by the biosphere.
Emissions Gap Report
Close on the heels of the WMO report on November 26, the United Nations Environmental Programme (UNEP) also released its annual Emissions Gap Report (EGR). The report has found that the world is not doing enough and emissions have only risen, hitting a new high of 55.3 gigatons (Gt) of CO2 equivalent in 2018. According to EGR-2019, even if all unconditional Nationally Determined Contributions (NDCs) under the Paris Agreement are implemented, the world is still on course for a 3.2°C temperature rise.
To get in line with the Paris Agreement, the EGR said, emissions must drop 7.6 per cent per year from 2020 to 2030 for the 1.5°C goal and 2.7 per cent per year for the 2°C goal. The size of these cuts, as the UNEP Executive Director Inger Andersen observed, may seem impossible, at least for next year. There is no sign of GHG emissions peaking in the next few years; every year of postponed peaking means that deeper and faster cuts will be required, the report says. “By 2030, emissions would need to be 25 per cent and 55 per cent lower than in 2018 to put the world on the least-cost pathway to limiting global warming to below 2°C and 1.5°C respectively.”
G20 members account for 78 per cent of global GHG emissions. According to the EGR, collectively, they are on track to meet their limited 2020 Cancun Pledges, but seven countries are currently not on track to meet 2030 NDC commitments, and for a further three it is not possible to say.
The report projects that six of the G20 members (China, the EU28, India, Mexico, Russia and Turkey) will meet their unconditional NDC targets with current policies. Among them, India, Russia and Turkey are projected to be more than 15 per cent lower than their NDC target emission levels. Australia, Brazil, Canada, Japan, the Republic of Korea, South Africa and the U.S. require further action of varying degree to achieve their NDCs.
“The findings of WMO’s Greenhouse Gas Bulletin and UNEP’s EGR point us in a clear direction—in this critical period, the world must deliver concrete, stepped-up action on emissions,” Inger Andersen said. “We face a stark choice: set in motion the radical transformation we need now, or face the consequences of a planet radically altered by climate change.” This will now be taken forward by the U.N. Climate Change Conference which will be held from December 2 to 15 in Madrid, Spain, under the presidency of Chile.