The fires in North America and Central Europe once again represent a sobering climate balance: the year 2023 was too hot again and records were broken worldwide. Climate researchers describe the last four months in particular as record-breaking. A hotter than average September was followed by a no less warm October. The autumn month was almost two degrees warmer than between 1850 and 1900 – the so-called pre-industrial comparison period. This applies not only to land areas, but also to the sea: temperatures there have never been as high as they were this October, write researchers from the climate change service of the European Earth observation program Copernicus (C3S).
Calculated over the year, the conclusion is: temperatures worldwide were 1.4 degrees above the estimated values of pre-industrialization.
Researchers at the Climate Change Service are therefore quite certain that 2023 could be the hottest year not only since weather records began, but in the last 125,000 years. To do this, the scientists combined their data with that of the Intergovernmental Panel on Climate Change (IPCC). This uses ice cores, tree rings and coral deposits to draw conclusions about the previous climate.
Now the question arises: How can one year not only beat the records from the era of man-made climate change, but also those before? There are a few reasons for this – and not all of them are just people.
Natural environmental events also influence the climate. This year it is primarily El Niño off the coast of Peru that can increase temperatures by 0.1 to 0.2 degrees and influence weather patterns, particularly in the southern Atlantic region. Its counterpart – La Niña – causes global temperatures to drop by an average of 0.1 degrees. Climate scientists predict El Niño began in the summer and will peak in December.
“We don’t expect record temperatures until next year because the global temperature increase will only become apparent with a delay of two to five months,” explained Josef Ludescher from the Potsdam Institute for Climate Impact Research (PIK) in an interview with stern. However, it cannot be ruled out that temperature records will be registered this year and will be broken again next year. Ludescher believes it is very likely that the 1.5 degree target could be exceeded at times.
It is the first time in eight years that an El Niño has occurred in the Atlantic. Previously, global average temperatures were slightly lowered by triple La Niñas. Given this background, the unusually high temperatures are not surprising.
Another important factor is the issue of air pollution. Greenhouse gases such as CO2, methane and fine dust are not only harmful to health but also harmful to the climate. Emissions can be released from anthropogenic sources such as traffic and wars, but also from natural sources such as volcanic eruptions. In order to meet the 1.5 degree target agreed in Paris, scientists believe that these gases must be urgently reduced. The International Energy Agency (IEA) has recently recorded record emissions every year. In 2022, global CO2 emissions in the energy sector rose by almost one percent to almost 37 gigatons. In Germany, emissions have fallen continuously since 1990.
Greenhouse gases determine how much solar radiation is reflected into space. Researchers have so far assumed that the higher the greenhouse gas content in the atmosphere, the more radiation is bound and the more the earth warms.
Using satellite images, an international team of researchers was also able to show that certain particles in the atmosphere, so-called aerosols, have a cooling effect on the planet. Because they not only reflect light, but can also change clouds – which in turn also reflect sun rays. The conclusion is that if the aerosols and clouds in the air evaporate, more radiation would hit the earth again and contribute to warming. This was also shown by the satellite images: According to this, the concentration of aerosols over North America and Europe has decreased since the turn of the millennium. During this time, warming increased by 15 to 50 percent. The study is currently being reviewed by independent experts and will then be published.
The oceans store heat, transport it over long distances using currents and thus regulate the climate. However, at the beginning of 2023, researchers noticed a worrying trend: the oceans are warming. The background has not yet been fully clarified, but scientists assume that climate change plays a role. If the ocean warms, periods of heat and cold can become more extreme. At the same time, more CO2 is released, which is actually stored in the depths of the ocean. If the chemical-physical properties of water change, the greenhouse gas is released into the atmosphere, where it prevents radiation from being reflected into space.
Climate researcher Josef Ludescher from PIk believes it is very likely that the 1.5 degree target will be exceeded at times next year. After that, temperatures could return to normal. Against the background of climate change, further temperature records are also possible with future El Niños. Ludescher’s conclusion: “If things continue like this, then even in the coldest La Niñas we will no longer be below 1.5 degrees. And then we will have permanently exceeded the 1.5 degree target, which could lead to a tipping of climate elements. “
The Paris climate goal aims to limit global warming to 1.5 degrees compared to the pre-industrial era. Global temperatures have already increased by almost 1.2 degrees since the mid-19th century. The United Nations expects that temperatures could rise to almost three degrees by the end of the century.
In its latest report, the European Environment Agency (EEA) assumes that the EU can reduce its emissions by 43 to 48 percent by 2030 compared to 1990. Actually it should be 55 percent. The Federal Association for Renewable Energy describes the results as “alarming”. If future climate protection measures were taken into account, the target would still be missed by seven percent. The association continues to push for an end to fossil energy – also in Germany. Researchers from the European climate change service Copernicus are also calling for “ambitious” agreements in the fight against global warming in the run-up to the upcoming UN climate conference in Dubai.
Sources: Copernicus Institute, Helmholtz Climate Initiative, Potsdam Institute for Climate Impact Research, Federal Environment Agency, International Energy Agency, Atmospheric Chemistry and Physics, “Süddeutsche Zeitung”, with material from DPA and AFP.
