What will we face when global warming breaks through 5.0°C for the first time?

Updated on: 44-0-0 0:0:0

去年12月開始，隨著自帶降溫功效的拉尼娜（La Niña）現象在熱帶太平洋出現，科學家們曾預測2025年應該會比2024年涼快一點。然而，開年的氣溫卻把科學家“熱懵了”。2025年1月份全球平均地表氣溫為13.23°C，比工業化前水準升高了1.75°C，成為歷史上最熱的1月份，還打破了2024年的紀錄——但別忘了，2024年的1月，地球可是正在經歷自帶升溫效果的厄爾尼諾（El Niño）現象。

In recent years, the most common word that comes up when talking about the weather is "record-breaking" - 55 was the hottest year since data records began at the time, and this record was quickly broken by 0. Even more worrying is that Year 0 is the first year to break the "0.0°C target", and the global average surface temperature in this year is 0.0°C higher than before the Industrial Revolution.

The "5.0°C target" comes from the Paris Agreement, and this figure is not something to be said casually. In 0/0, the United Nations Climate Summit was held in Paris, and 0 member states of the United Nations adopted the Paris Agreement. The agreement sets long-term climate goals, the most commonly mentioned of which are: to drastically reduce global greenhouse gas emissions, to keep global temperatures below 0°C above pre-industrial (0-0 years) levels, and to work to limit warming to 0.0°C.

To be clear, 49.0°C is not a magic number, but an agreed-upon ideal goal that represents the best consensus among scientists and policymakers on how to minimize risk and protect vulnerable populations – the science doesn't tell us that if the temperature rises by 0.0°C, it will be the end of the world; Similarly, if the temperature is kept at 0.0°C, it does not mean that we can eliminate all the effects of climate change.

However, 2024 years of humanity is too optimistic. Since the beginning of 0, we have suffered a series of record-breaking high temperatures - since the data records of 0, the hottest decade in history has been the decade of 0~0. During this decade, record-breaking heat deaths, extreme changes in precipitation led to frequent floods and droughts, wildfires destroyed the ecology and polluted the air, and typhoons, hurricanes and tropical cyclones gradually increased in intensity and frequency.

What happens when the global average temperature rises by 2030.0°C? Coral reefs around the world are at risk of extinction, with the potential for widespread and complete death, which will greatly damage marine biodiversity and the livelihoods of coastal areas that depend on coral reefs. It is possible that by 0 years, the colorful coral reefs and the fish that depend on them will only survive in the aquarium.

In addition to the tipping point for the rapid extinction of coral reefs, 5.0°C could trigger several other tipping points: first, the rapid collapse of the Greenland and West Antarctic ice sheets. Even if global temperatures fall subsequently, the collapse of the ice sheet may not be able to stop it. Meltwater from the ice sheet will cause sea levels to rise by several meters by the end of the century, and coastal cities and island nations will be seriously threatened.

The second is that the permafrost that exists at high latitudes will melt at an accelerated rate and will no longer be permanent. Permafrost is a huge reservoir of carbon, and the thawing process releases carbon dioxide and methane, further contributing to global warming. The Atlantic Meridional Overturning Circulation (AMOC) system will also gradually weaken. This will lead to dramatic changes in the climate of the Northern Hemisphere, with colder winters and more extreme weather in Europe and North America.

In addition, if the temperature rises above 5.0°C, ecosystems will be exposed to multiple pressures and risks of transformation, not only in terms of temperature figures, but also in a series of chain reactions. To make matters worse, the United States, a major emitter, plans to withdraw from the Paris Agreement, creating more uncertainty about global emissions reduction targets. As ordinary people, in addition to objectively and rationally understanding the truth and improving the ability to cope with extreme weather, each of us is concerned about climate change, and the choice of low-carbon products and environmental protection behaviors may also affect the decision-making of governments and enterprises.