All the alarms have gone off before what can happen this year with the world climate. The more than likely arrival of an episode of The boy could raise temperatures across the planet in ways never seen before. The Earth could increase its temperature to the critical threshold (1.5 degrees above the pre-industrial level) this very summer.
The clear weakening of La Niña, (which has been cooling the planet’s thermometers for the last three years), and the increasing probabilities (already close to 60%) that the Pacific is dominated by El Niño starting in summer, have put meteorologists on alert. Experts monitor the natural cycle of El Niño-Southern Oscillation (ENSO) in the face of a possible increase in global temperature, even above that registered last year.
La Niña has been conditioning the planet’s climate for three consecutive years. “The first event appeared in 2020 and was later linked to two others that have been modulating the climate up to the present moment,” explains the meteorologist and scientific popularizer José Miguel Viñas. Now La Niña shows clear signs of weakening and it is not ruled out that El Niño, upon finding free ground, may take over and regain strength.
La Niña and El Niño are phenomena that modulate the Earth’s climate from the Pacific Ocean. La Niña tends to cool those waters and, consequently, the rest of the planet, while El Niño tends to do the opposite, warm them. The phenomenon is repeated in a cyclical way, and is interspersed with moments of neutral conditions. Each of them can last between 2 and 7 years.
This 2023 has all the ballots to become a year of transition from La Niña to Niño, going through a neutral phase. The large international centers for monitoring the ENSO cycle have already made their predictions. In principle, the February-March-April quarter has at least an 80% chance of returning to neutral temperature conditions in the Pacific. What is less clear is what will happen after the summer.
Are the 1.5ºC already here?
The probabilistic models forecast the return of El Niño with a probability greater than 50% from the second half of 2023, when the normal thing is that said percentage is between 25% and 50%. And although at the moment these models must be ‘taken with tweezers’, the experts already warn that, if they occur, it is likely that global temperatures will be reached 1.5ºC above the pre-industrial period.
1.5ºC is the level that the Paris Agreement established as a critical temperature threshold in a context of climate change. It is also the temperature that countries pledged not to exceed at the end of the century. However, the signatories were also aware that there could be specific years in which the threshold was exceeded. “The important thing about this agreement is that it advocated stabilizing the temperature at 1.5ºC before 2030,” Viñas emphasizes. Despite this, it is notorious that the Earth can reach that limit eight years before the established date.
What has most attracted the attention of scientists is that, In a period in which the cold should have been noticeable, what has stood out in most of the planet is the sweltering heat. Last year temperature records were broken across the planet. As stated in the ‘Global Climate 2022’ report from the Copernicus Climate Change Service, during the year the average temperature was 0.3°C above that of the period between 1991-2020 and 1.2°C above the that was recorded during the pre-industrial period (1850-1900).
In this way, 2022 became the eighth consecutive year with temperatures more than one degree Celsius above those of the pre-industrial level, with thermometers that were more than 2°C above the average for the period 1991-2020 in areas of the northern central Siberia and along the Antarctic Peninsula.
“If there had not been La Niña, we would probably be talking about an increase in global temperatures that would already exceed 1.4ºC. instead of the current 1.2ºC”, explains Viñas, alluding to the cooling effect that this phenomenon entails.
It is true that this increase in temperature has not been uniform throughout the world. La Niña caused a drop in temperatures in the Pacific, meaning Australia and South America were cooler than average in 2022.
unprecedented heat waves
What consequences can the arrival of El Niño have? Thermal anomalies will likely be higher than they have been in recent years, which may mean an increase in heat waves and a greater impact from storms and tropical cyclones. Therefore, the planet could face unprecedented temperatures this year. Of course, for the moment, “everything is prediction” and it is necessary to continue monitoring to better understand the global phenomenon, the experts insist.
But also, A scientific study has just warned that El Niño could cause an “irreversible” thaw of the ice shelves and plates in Antarctica. The investigation of the scientific agency of the Government of Australia (CSIRO, acronym in English) concluded, after analyzing 31 models, that the increasing changes in El Niño would translate into a decrease in the temperature of surface waters, but in an increase in the underwater water temperature.
“This new research shows that a more intense El Niño can accelerate the warming of the deep waters of the Antarctic shelf, causing ice shelves and sheets to melt faster», explained Wenju Cai, lead author of this research.
The scientific community, in short, remains alert to what may happen in the coming months, although everything points to the fact that 2023 could once again give quite striking headlines in terms of climate.
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INTERVIEWDesislava Petrova. Researcher at the Institute for Global Health (ISGlobal).
«During ‘El Niño’, the ocean releases more heat into the atmosphere»
-What effects do El Niño and La Niña have on the planet’s climate?
-El Niño events are associated with abnormally warm ocean surface temperatures in the eastern Pacific Ocean, while La Niña events are associated with cold anomalies. These temperature changes change evaporation rates, which can affect tropospheric circulation and cloud formation, as well as net heat fluxes to other regions of the world. ENSO is a factor driving the climate connections, as it affects the location and intensity of the jet stream in mid-latitudes. This current, in turn, triggers atmospheric waves that propagate to both hemispheres. It is this atmospheric bridge that links ocean thermal anomalies in the Pacific with lagged climate changes in many tropical and extratropical regions of the world. These changes can be expressed in an increase or decrease in temperatures and in an increase in rainfall or drought, for example.
-Does this natural cycle contribute to climate change?
No, it doesn’t do it directly. However, when the warm phase of the cycle occurs, the ocean releases more heat into the atmosphere, which has the capacity to raise global temperatures during the year in which it occurs. For this reason, the next big El Niño will most likely coincide with a new record making the year the warmest on record.
-There is more than a 50% chance that El Niño will take place this summer, how will it affect Spain if this happens?
-An El Niño event that gains intensity can have effects on temperatures and precipitation in the Iberian Peninsula, although La Niña has traditionally had more impact in the region. When El Niño reaches its peak in the Pacific, probably in winter, it could bring more moisture to western and central Spain.
-Taking into account that the planet has been under La Niña in the last three years, what do you think about the temperature record reached in 2022?
-It is probably a sign that climate change is accelerating. Taking into account that La Niña cools the average temperatures of the planet, but that it has not been possible to perceive it in the planet as a whole during the last two years in which we have had this phenomenon, it is most likely that a faster increase is taking place in global temperature from burning fossil fuels. That is, warming has accelerated.
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