MOSCOW, May 25, Vladislav Strekopytov. The World Meteorological Organization (WMO) has said the relatively cool climate phase is over. A hot El Niño period is on the way, causing some areas to experience extreme drought and others to experience extreme rainfall and flooding. Not good in the long run either: By the year 2100, the surface temperature of the Earth will rise by 2.7 degrees, and 22 percent of the population will change their place of residence due to unbearable heat.
Insidious El Niño
Every year in May, the WMO releases the GADCU (Global Annual to Decadal Climate Update) report. It provides the main climatic parameters: the average temperature for the year, pressure, precipitation, as well as the phase states of the main ocean processes that affect the planet's climate — the North Atlantic Oscillation (AMO) and El Niño/Southern Oscillation (ENSO). A separate section of the document is devoted to the forecast for the next year and for five years.
A new report says that the cold La Niña phase associated with the Southern Oscillation phenomenon in the equatorial Pacific will end in the middle of the year. This time it was abnormally long — three and a half years instead of the usual one or two. Experts fear that the energy accumulated in the global climate system, held back by La Niña mechanisms, may spill out onto the planet with unpredictable force.
The El Niño phenomenon is associated with an anomalous heating of water that occurs every few years in the central and eastern parts of the Pacific Ocean. The heat from the ocean is transferred to the atmosphere and leads to an increase in temperature around the globe by about 0.1 degrees. As part of natural fluctuations, this growth is compensated during the La Niña period. But in the last hundred years, the atmosphere during the cool phase does not cool down, but continues to heat up, but more slowly.
Thus, the average global temperature in 2022, despite the cooling effect of La Niña, was about 1.15 degrees above the average for the pre-industrial period (1850-1900), and its growth over the past decade was 0.2 degrees.< br />The previous temperature record was observed in 2016, also during the El Niño phase. There is every chance that he will be beaten in 2024. WMO climatologists suggest that the next five years with a 66 percent probability will become the hottest in the history of meteorological observations, and the average annual temperature will exceed 1.5 degrees Celsius before 2027, the value indicated in the Paris Agreement as a target until 2100.
Scientists predict a record heat wave around the globe, but above all — in the tropical zone between 30 parallels of northern and southern latitudes, where more than a third of the world's population lives.
Human measurement of heat
According to an international team of climate scientists who published an article in the journal Nature Sustainability, such a massive increase in temperature will lead to «existential risk» for millions of people. The results of the modeling performed by the authors show that by the end of the 21st century, the temperature of the Earth's surface will rise by 2.7 degrees Celsius compared to pre-industrial levels.
Because of this, 22 percent of the predicted population of the planet — more than two billion people — will be outside the climate comfort zone, which is limited by the isotherm of the average annual temperature of 29 degrees. Studies have shown that sustained temperatures above this threshold are associated with higher mortality, lower productivity and yields, and more conflict and infectious disease.
Even 40 years ago, no more than 12 million people lived in an extremely hot climate. Today, their number has increased fivefold, and will grow even faster in the coming decades. According to climatologists, by 2100, most of the inhabitants of India (600 million), Nigeria (300 million), Indonesia (100 million), as well as the Philippines and Pakistan (80 million each) will be outside the favorable zone.
“Every 0.1 degree of warming exposes an additional 140 million people to dangerous heat,” lead author Timothy Lenton, director of the Global Systems Institute, is quoted in a press release from the University of Exeter. “The costs of global warming are often estimated in financial terms. Our study is the first highlights the human cost of failing to cope with a climate emergency.»
Climate Migrants
Researchers note that a 2.7-degree rise in average temperatures by the end of the century is a realistic scenario. But the worst scenarios cannot be ruled out, in which temperatures will rise by 3.6-4.4 degrees. In this case, up to 50 percent of the world's population will be outside the favorable climatic niche.
«This could lead to a large-scale transformation of the Earth's surface and fundamentally change the habitability of our planet,» says Lenton.
Historically, humanity has been concentrated in two climatic zones: in temperate latitudes with an average annual temperature of about 13 degrees and in zones of tropical monsoon climate, where this value is on average at the level of 27 degrees. The first accounts for the maximum of world GDP as an indicator of the well-being of the population, the second — the main volume of production of agricultural crops and livestock.
In recent years, the second peak in the human distribution diagram has gradually shifted towards a cold climate. This suggests that more and more people are moving from warm, traditionally agricultural regions to mid-latitudes. The authors warn that climate migration will only pick up pace, reaching billions of people in the worst-case scenario.