The concentration of greenhouse gases in the atmosphere has never risen as quickly as it did last year. The reasons: human activity, the El Niño weather phenomenon and droughts in the tropics.
GenevaAccording to measurements by climatologists, the greenhouse gas concentration in the atmosphere has never risen as quickly as it did last year. In addition to the activities of the people, this was also due to the El Niño weather phenomenon with its increased ocean temperatures and droughts in the tropics, as the World Weather Organization (WMO) reported in Geneva on Monday. As a result, oceans and forests, for example, could not absorb as much climate-damaging carbon dioxide (CO2) as in other years.
The new WMO greenhouse gas bulletin, together with the report of the UN Environment Program (UNEP) planned for Tuesday on progress in reducing greenhouse gases, will serve as the basis for the climate conference in Bonn from November 6th. Unep’s “Emissions Gap Report” shows what the world’s population still has to do to limit global warming to below two degrees by the end of the century, as laid down in the Paris World Climate Agreement.
WMO General Secretary Petteri Taalas sounded the alarm: “Without rapid cuts in CO2 and other greenhouse gas emissions, we will be heading for dangerous increases in temperature by the end of the century that are well above the goals of the Paris Agreement. Future generations will inherit a much more inhospitable planet. “
According to the WMO, the CO2 concentration in the atmosphere was 403.3 parts per million particles (ppm), compared to 400 ppm in the previous year. The most recent growth record of well below 2 ppm came from 2013. In 1996 the concentration was only 362 ppm. The US climate agency NOAA reported a CO2 concentration of 402.9 ppm for the past year. The WMO would take measurements from twice as many stations as the NOAA, said WMO climate researcher Oksana Tarasova.
Until the beginning of industrialization around 1750, the concentration remained below 280 ppm for at least 800,000 years, the report says. This is proven by ice drilling, in which correspondingly old air bubbles were discovered, which made it possible to measure the concentration at that time. After analyzing fossils, researchers estimate that there was a CO2 concentration as high as it was three to five million years ago. It was two to three degrees warmer. The ice in Greenland and West Antarctica has melted and the sea level has been 10 to 20 meters higher.
If the CO2 level continues to rise rapidly, this can trigger unprecedented climate changes, with “serious ecological and economic disruptions,” warns the WMO. In addition to population growth, more intensive agriculture and deforestation, industrialization and the associated use of fossil fuels contribute to high greenhouse gas concentrations.
CO2 is the most important long-lived greenhouse gas: the combustion of coal, oil and gas, cement production and other industrial processes cause around 70 percent of all greenhouse gas emissions. According to the report, the CO2 concentration was 145 percent compared to the pre-industrial level in 2016, the second most important greenhouse gas methane was 257 percent and the third most important, nitrous oxide (laughing gas), 122 percent.
Global CO2 emissions have remained practically at the same level over the past three years. But the concentration in the atmosphere increases even if the emissions remain high. Around a quarter of the CO2 emitted is currently absorbed by the oceans, which become more acidic. Another quarter stores the biosphere, for example trees and soil. The rest ends up in the atmosphere. The radiative forcing, which measures the climate-relevant effects of greenhouse gases, has increased by 40 percent since 1990, of which by 2.5 percent in 2016 alone, according to the report. CO2 is responsible for 80 percent of the increase since 1990.