Teams of meteorologists around the world predict that the world is gradually approaching the threshold of warming that international agreements are trying to prevent. In the next five years, there is almost half the possibility that the earth will temporarily reach this temperature mark A team of 11 different prediction centers made predictions for the World Meteorological Organization late Monday - with the continuation of man-made climate change, there is a 48% chance that the world will reach an annual average temperature of 1.5 degrees Celsius higher than the pre industrial level at the end of the 19th century at least once between now and 2026, which is a bright red signal in climate change negotiations and science.
This probability is rising as the thermometer rises. Last year, the same forecasters thought the odds were close to 40%, up from 10% a decade ago.
The team coordinated by the Met Office pointed out in their five-year overall outlook that by the end of 2026, there is a 93% chance that the world will set a record for the hottest year. They also said that the five years from 2022 to 2026 will be the hottest year on record, with a 93% chance. Forecasters also predict that the catastrophic drought prone to fire in the southwestern United States will continue.
Leon Hermanson, a senior scientist at the Met Office who coordinated the report, said: "we will see continued warming, which is consistent with climate change expectations."
These forecasts are based on long-term averages and state-of-the-art computer simulations, and predict the overall situation of global and regional climate on annual and seasonal time scales. They differ from increasingly accurate weather forecasts that predict how hot or wet it will be in a particular place on a given day.
But even if the world reaches the mark of 1.5 degrees higher than in the pre industrial period - the global warming has been about 1.1 degrees since the end of the 19th century - it is not quite the same as the global threshold first set by international negotiators in the 2015 Paris Agreement. In 2018, an important United Nations Scientific report predicted that if the climate warms more than 1.5 degrees, it will have a huge and dangerous impact on mankind and the world.
Several scientists said that the global threshold of 1.5 degrees means that the world is not in one year, but in 20 or 30 years. This is not what the report predicts. Hermanson said meteorologists can only know years after the Earth actually reaches the average mark, perhaps ten or twenty years later, because it is a long-term average.
"This is a warning of the average level in a few years," said Natalie Mahowald, a climate scientist from Cornell University. He is not a member of the prediction team.
Zeke hausfather, a climate scientist at technology companies stripe and Berkeley earth, pointed out that this prediction is meaningful given that the world is already warm and is expected to increase by one tenth of a degree Celsius in the next five years due to human induced climate change. It is reported that hausfather is not in the prediction group. Coupled with the possibility of a strong El Ni ñ o phenomenon - natural periodic warming in some parts of the Pacific has changed the world weather - this may throw another dozens of temperatures above temporarily, and the world will reach 1.5 degrees.
Scientists say the world is in the second consecutive year of La Nina. The La Nina site is opposite to the El Nino phenomenon, which has a slight global cooling effect, but is not enough to offset the overall temperature rise of the heat generating gas emitted by the combustion of coal, oil and natural gas. The five-year forecast indicates that La Nina may end by the end of this year or 2023.
The greenhouse effect of fossil fuels is like putting the global temperature on a rising escalator. Scientists say El Nino, La Nina and other natural weather changes are like steps up or down this escalator.
On a regional scale, the Arctic will still warm at a rate three times higher than the global average temperature in winter. The report predicts that although the southwestern United States and southwestern Europe may be drier than normal in the next five years, Africa's often arid Sahel region, northern Europe, northeastern Brazil and Australia are expected to be wetter than normal.
Hermanson points out that the global team has made these predictions informally for ten years and formally for about five years, with an accuracy of more than 90%.
Gavin schmidit, NASA's top climate scientist, said the figures in the report were "slightly warmer" than those used by NASA and NOAA. In addition, he expressed doubts about the skill level of long-term regional prediction.
"Whatever the prediction here, we are very likely to exceed 1.5 degrees Celsius in the next decade or so, but that doesn't necessarily mean that our long-term commitment to this - or efforts to reduce further changes are not worth it," schmidit said in an email.