Carbon dioxide and methane reach new record values ​​- Knowledge

Around ten days before the start of the COP27 world climate conference in Egypt, several reports from UN organizations show how far the world is lagging behind in combating global warming. For example, the Geneva-based World Weather Organization (WMO) explained in its annual greenhouse gas bulletin that the atmospheric concentrations of the three most important greenhouse gases carbon dioxide (CO₂), methane and nitrous oxide have each reached new highs in 2021. The increase in methane levels last year was stronger than at any time in the past four decades. At the same time, the climate promises made by the nation states are still insufficient to comply with the temperature limits set in the Paris Climate Agreement, as the UN Climate Change Secretariat UNFCCC reports.

According to WMO calculations, the proportion of the most important greenhouse gas, carbon dioxide, reached a record level of 415 parts per million air molecules in 2021, which corresponds to 149 percent of the pre-industrial value. This is mainly due to the continued burning of fossil fuels, but also to industrial processes such as cement production. So far, it cannot be said that the increase in CO₂ concentration is slowing down; on the contrary, the annual increase has been above average if you look at the past ten years.

The experts are puzzled by the rapid increase in the methane content. The increases in CH₄ concentration in 2020 and 2021 were the strongest since systematic measurements began in 1983. “The reason for this extraordinary increase is not clear, but appears to be due to both biological and man-made processes,” reported the WMO.

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The current climate targets of the states would lead to a warming of 2.5 degrees

Much of the methane probably comes from wetlands and rice paddies. It is still unclear whether this is a consequence of climate change, for example because wetlands are becoming wetter and warmer and therefore more organic material is broken down. Degradation in water without oxygen supply also leads to higher methane emissions. But the WMO also writes: “The dramatic increase could also be due to natural annual variability.”

Methane is the second largest contributor after carbon dioxide climate change at. It is created where organic material is broken down in the absence of air. Over a 100-year period, it is around 28 times more harmful to the climate than CO₂, but remains in the atmosphere for much less time. In the case of methane it is a good ten years, in the case of CO₂ a considerable proportion is still present in the atmosphere even after centuries. CO₂ contributes around two thirds to the greenhouse effect, methane a good 16 percent and nitrous oxide around 6.5 percent. All greenhouse gases combined have led to an average global warming of 1.1 degrees since the late 19th century. In Germany it was 1.6 degrees.

A report by the UN Climate Change Secretariat UNFCCC on the national climate protection goals of the states also shows that this warming trend has continued unabated to date. If all of these commitments were met, emissions in 2030 would still be 10.6 percent higher than in 2010. Limiting global warming to 1.5 degrees by 2100, as envisaged in the Paris climate agreement, would require a reduction of 43 to 45 percent by 2030, compared to the base year 2010. According to climate researchers, compliance with the 1.5-degree target would be important in order to prevent serious consequences of global warming such as increasing droughts or heat waves. However, it is increasingly out of reach. The current targets are moving closer to a warming of 2.5 degrees Celsius by the end of the century.

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Nevertheless, the authors of the UNFCCC report see some progress. Last year, the climate targets of the states indicated an increase in emissions of 13.7 percent by the end of the decade. The fact that it is now at least three percentage points lower is due to the fact that some countries have lowered their climate targets since the last climate conference have tightened. However, only 24 countries have presented new or revised targets – despite the fact that all states promised to do so at COP26 in the UK.

With material from dpa

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